Fastening tool

Abstract

A fastening tool is provided that is capable of controlling the moving speed of a screwdriver bit by an action of moving the screwdriver bit in the direction of a fastening screw. The fastening tool (1) is provided with: a bit holding portion (3) that holds a screwdriver bit (2) in a detachable manner and is capable of rotating in the circumferential direction of the screwdriver bit (2) and is capable of moving in the axial direction; a bit rotating motor (40) that rotates the bit holding portion (3); a bit moving motor (50) that moves the bit holding portion (3) in the axial direction; and a control portion (100) that controls the position of the bit holding portion (3) in the axial direction with the number of revolutions of the bit moving motor (50), the control portion (100) performing control so that the moving speed of the bit holding portion (3) that moves by the rotation of the bit moving motor (50) follows the moving speed at the time when the screw moves while the screw is fastened to a fastening object by the rotation of the bit rotating motor (40).

Description

Technical Field

[0001] This invention relates to a fastening tool that engages a screwdriver bit with a screw, presses the screw with the screwdriver bit to press the screw onto the object to be fastened, and rotates the screwdriver bit to screw it in. Background Technology

[0002] A movable tool called a nail-driving machine is known that uses the air pressure of compressed air supplied from an air compressor and the combustion pressure of a gas to sequentially drive out connecting stops loaded in a nail box from the front end of a screwdriver guide.

[0003] In the past, among the tools that rotate the bit to tighten the screw and move the bit in the direction of tightening the screw, a pneumatic screw drive has been proposed, which uses a pneumatic motor to rotate the bit and uses air pressure to move the bit in the direction of tightening the screw (for example, see Patent Document 1).

[0004] In addition, a screw-driving machine is proposed that uses the driving force of a motor that rotates the screw to compress a spring, and uses the force of the spring to drive the screw in (for example, see Patent Document 2).

[0005] Patent Document 1: Japanese Patent No. 5262461

[0006] Patent Document 2: Japanese Patent No. 6197547 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In tools with a structure that moves the bit toward the fastening screw, the faster the bit's forward speed is than the screw's forward speed, which is determined by the screw's rotational speed, the greater the reaction force that causes the tool body to detach from the fastening object. If the reaction force is greater, it may be possible to lift the tool body off the fastening object by resisting the force applied by the operator pressing the tool body against it.

[0009] However, when the tool body lifts off the object being tightened due to the reaction force, the operation may sometimes be completed without the screw being fully tightened. Therefore, to improve the quality of screw tightening, it is necessary to suppress the reaction force, that is, to coordinate the screw's rotation speed so that the bit moves (advances) at an appropriate speed.

[0010] However, conventional fastening tools lacked a design that used rotational speed to control the forward speed of the screwdriver bit. Furthermore, screwdrivers that use air pressure or spring force to drive in screws struggled to control the bit's movement speed by manipulating the action of the screwdriver bit towards the screw.

[0011] This invention was made to solve such a problem, and its object is to provide a fastening tool that can control the movement speed of the screwdriver bit by using an action that moves the screwdriver bit in the direction of fastening the screw.

[0012] Technical solutions for solving the problem

[0013] To address the aforementioned issues, the present invention provides a fastening tool comprising: a bit holder for holding a screwdriver bit in a detachable manner, and capable of rotating circumferentially and moving axially; a first motor for rotating the bit holder; a second motor for moving the bit holder axially; and a control unit for controlling the axial position of the bit holder by the rotation speed of the second motor, wherein the control unit controls the movement speed of the bit holder, which is moved by the rotation of the second motor, to follow the movement speed of the screw when it is fastened to the fastening object by the rotation of the first motor.

[0014] In this invention, the moving speed of the screwdriver bit follows the moving speed of the screw when the screw is fastened to the object being fastened.

[0015] Furthermore, the present invention is a fastening tool comprising: a bit holding portion for holding a screwdriver bit in a detachable manner, and capable of rotating in the circumferential direction and moving in the axial direction of the screwdriver bit; a first motor for rotating the bit holding portion; a second motor for moving the bit holding portion in the axial direction; and a control unit for controlling the axial position of the bit holding portion using the rotational speed of the second motor, wherein the control unit controls the moving speed of the bit holding portion based on the rotation of the second motor relative to the rotational speed of the first motor.

[0016] In this invention, the moving speed of the screwdriver bit can be controlled by the action of pressing the screw against the fastening object and the action of fastening the screw to the fastening object, respectively.

[0017] Invention Effects

[0018] In this invention, the moving speed of the screwdriver bit can be controlled by the action of moving the screwdriver bit in the direction of tightening the screw. Attached Figure Description

[0019] Figure 1A This is a side sectional view showing an example of the internal structure of the fastening tool of this embodiment.

[0020] Figure 1B This is a top sectional view showing an example of the internal structure of the fastening tool of this embodiment.

[0021] Figure 1C This is a front sectional view showing an example of the internal structure of the fastening tool of this embodiment.

[0022] Figure 2A This is an exploded perspective view showing an example of the internal structure of the fastening tool according to this embodiment.

[0023] Figure 2B This is a perspective view showing an example of the fastening tool of this embodiment.

[0024] Figure 3A This is a perspective view showing an example of the main structure of the fastening tool according to this embodiment.

[0025] Figure 3B This is a perspective view showing an example of the main structure of the fastening tool according to this embodiment.

[0026] Figure 4A This is a cross-sectional perspective view showing an example of the main structural components of the fastening tool according to this embodiment.

[0027] Figure 4B This is a cross-sectional perspective view showing an example of the main structural components of the fastening tool according to this embodiment.

[0028] Figure 4C This is a cross-sectional perspective view showing an example of the main structural components of the fastening tool according to this embodiment.

[0029] Figure 5 This is a top sectional view showing an example of the main structural components of the fastening tool according to this embodiment.

[0030] Figure 6A This is a top sectional view showing an example of the internal structure of the fastening tool of this embodiment.

[0031] Figure 6B This is a top sectional view showing an example of the internal structure of the fastening tool of this embodiment.

[0032] Figure 7A This is a cross-sectional view showing an example of a disassembly and assembly retention mechanism.

[0033] Figure 7B This is a cross-sectional view showing an example of a disassembly and assembly retention mechanism.

[0034] Figure 8A This is a perspective view showing an example of a disassembly and assembly retention mechanism.

[0035] Figure 8B This is a perspective view showing an example of a disassembly and assembly retention mechanism.

[0036] Figure 9 This is a perspective view showing an example of the screw feed section and the machine head of this embodiment.

[0037] Figure 10AThis is a perspective view taken from the rear, showing an example of the fastening tool of this embodiment.

[0038] Figure 10B This is a perspective view taken from the rear, showing an example of the fastening tool of this embodiment.

[0039] Figure 10C This is a perspective view taken from the rear, showing an example of the fastening tool of this embodiment.

[0040] Figure 11 This is a three-dimensional diagram representing an example of a design department.

[0041] Figure 12 This is a block diagram illustrating an example of the fastening tool of this embodiment.

[0042] Figure 13A This is a side sectional view illustrating an example of the operation of the fastening tool in this embodiment.

[0043] Figure 13B This is a top sectional view showing an example of the operation of the fastening tool in this embodiment.

[0044] Figure 14 This is a flowchart illustrating an example of the operation of the fastening tool in this embodiment.

[0045] Figure 15A It is a cross-sectional view showing the tightened state of the screw.

[0046] Figure 15B It is a cross-sectional view showing the tightened state of the screw.

[0047] Figure 15C It is a cross-sectional view showing the tightened state of the screw.

[0048] Figure 16A This is an explanatory diagram illustrating an example of setting the standby positions of the holding and moving components during the first initialization operation.

[0049] Figure 16B This is an explanatory diagram illustrating an example of setting the standby positions of the holding and moving components during the first initialization operation.

[0050] Figure 16C This is an explanatory diagram illustrating an example of setting the standby positions of the holding and moving components during the first initialization operation.

[0051] Figure 16D This is an explanatory diagram illustrating an example of setting the standby positions of the holding and moving components during the first initialization operation.

[0052] Figure 17AThis is an explanatory diagram illustrating an example of the action of moving the holding component and the moving component to the standby position during the second initialization operation.

[0053] Figure 17B This is an explanatory diagram illustrating an example of the action of moving the holding component and the moving component to the standby position during the second initialization operation.

[0054] Figure 17C This is an explanatory diagram illustrating an example of the action of moving the holding component and the moving component to the standby position during the second initialization operation.

[0055] Figure 18 This is a flowchart illustrating an example of selecting the first initialization action and the second initialization action.

[0056] Figure 19 This is a flowchart illustrating a variation of the operation of the fastening tool in this embodiment.

[0057] Figure 20 It is a graph showing the relationship between the output of the contact switch and the control of the bit rotation motor and bit movement motor.

[0058] Figure 21 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0059] Figure 22A It is a graph showing the relationship between load and the control of the bit rotation motor.

[0060] Figure 22B It is a graph showing the relationship between load and the control of the bit rotation motor.

[0061] Figure 23 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0062] Figure 24A It is a graph showing the relationship between the rotational speed of the bit rotary motor and the bit moving motor based on feedback control.

[0063] Figure 24B It is a graph showing the relationship between the screw movement speed caused by the rotation of the bit rotary motor based on feedback control and the screw bit movement speed caused by the bit movement motor.

[0064] Figure 25 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0065] Figure 26A It is a graph showing the relationship between the load and the control of the bit movement motor.

[0066] Figure 26BIt is a graph showing the relationship between the load and the control of the bit movement motor.

[0067] Figure 27 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0068] Figure 28 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0069] Figure 29 This is a block diagram illustrating other variations of the operation of the fastening tool in this embodiment.

[0070] Figure 30 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0071] Figure 31 This is a flowchart illustrating other variations of the operation of the fastening tool in this embodiment.

[0072] Figure 32 It is a graph showing the relationship between the load during screw tightening and the control of the bit movement motor.

[0073] Figure 33 It is a diagram showing the engagement state between the screwdriver bit and the groove of the screw when the screw is tightened. Detailed Implementation

[0074] Hereinafter, embodiments of the fastening tool of the present invention will be described with reference to the accompanying drawings.

[0075] <Example of the structure of the fastening tool in this embodiment>

[0076] Figure 1A This is a side sectional view showing an example of the internal structure of the fastening tool according to this embodiment. Figure 1B This is a top sectional view showing an example of the internal structure of the fastening tool according to this embodiment. Figure 1C This is a front sectional view showing an example of the internal structure of the fastening tool according to this embodiment. Additionally, Figure 2A This is an exploded perspective view showing an example of the internal structure of the fastening tool according to this embodiment. Figure 2B This is a perspective view showing an example of the fastening tool of this embodiment.

[0077] The fastening tool 1 of this embodiment includes: a bit holding part 3 for holding a screwdriver bit 2 in a rotatable and axially movable manner; a first drive part 4 for rotating the screwdriver bit 2 held by the bit holding part 3; and a second drive part 5 for moving the screwdriver bit 2 held by the bit holding part 3 axially.

[0078] In addition, the fastening tool 1 includes: a screw storage section 6 for storing screws 200; a screw feed section 7 for feeding the screws stored in the screw storage section 6; and a head 8 for pressing against the object to be fastened by the screws 200 and for ejecting the screws.

[0079] Furthermore, the fastening tool 1 includes a tool body 10 and a handle 11. In addition, the fastening tool 1 has a battery mounting part 13 at the end of the handle 11 for detachably mounting the battery 12.

[0080] The tool body 10 of the fastening tool 1 extends in one direction along the axial direction of the screwdriver bit 2, as indicated by arrows A1 and A2, while the handle 11 extends in another direction intersecting the extension direction of the tool body 10. The fastening tool 1 has its front-to-back direction along the extension direction of the tool body 10, i.e., the axial direction of the screwdriver bit 2, as indicated by arrows A1 and A2. Furthermore, the fastening tool 1 has its up-and-down direction along the extension direction of the handle 11. Moreover, the fastening tool 1 has its left-to-right direction in a direction orthogonal to the extension directions of both the tool body 10 and the handle 11.

[0081] The first drive unit 4 is located on one side of the tool body 10, i.e., at the rear, across the handle 11. The second drive unit 5 is located on the other side of the tool body 10, i.e., at the front, across the handle 11.

[0082] The screw storage section 6 stores multiple screws 200 connected by a connecting strap and wound into a spiral shape.

[0083] Figure 3A , Figure 3B This is a perspective view showing an example of the main structural components of the fastening tool according to this embodiment. Figures 4A to 4C This is a cross-sectional perspective view showing an example of the main structural components of the fastening tool according to this embodiment. Figure 5 This is a top sectional view showing an example of the main structure of the fastening tool according to this embodiment, detailing the bit holding part 3 and the first drive part 4. Next, the bit holding part 3 and the first drive part 4 will be described with reference to the figures.

[0084] The bit holding part 3 is an example of a front-end tool holding part, and includes: a holding member 30 for holding a screwdriver bit 2, which is an example of a front-end tool, in a detachable manner; a rotation guide member 31 for supporting the holding member 30 in a manner that allows it to move in the front-back direction along the axis of the screwdriver bit 2 as indicated by arrows A1 and A2, and for rotating together with the holding member 30; a moving member 32 for moving the holding member 30 in the front-back direction along the rotation guide member 31; and a force applying member 33 for applying force to the moving member 32 in the rearward direction as indicated by arrow A2.

[0085] The outer diameter of the retaining member 30 is slightly smaller than the inner diameter of the rotary guide member 31, and it is constructed from a cylindrical component that enters the inner side of the rotary guide member 31. The retaining member 30 has an opening 30a at its front end along the axial direction of the screwdriver bit 2, the shape of which matches the cross-sectional shape of the screwdriver bit 2. The retaining member 30 has a detachable retaining mechanism 30c at the opening 30a to detachably retain the screwdriver bit 2. The opening 30a of the retaining member 30 protrudes inside the rotary guide member 31, and the screwdriver bit 2 is detachably inserted into the opening 30a.

[0086] The rotary guide member 31 extends along the extension direction of the tool body 10, i.e., along the axial direction of the screwdriver bit 2, as indicated by arrows A1 and A2. The rotary guide member 31 is a cylindrical shape in which the retaining member 30 is inserted inside. Its front end is rotatably supported by a bearing 34a, which serves as an example of a bearing, on a metal front frame 10b provided on the front side of the resin housing 10a that constitutes the outer casing of the tool body 10. Furthermore, the rear end of the rotary guide member 31 is connected to the first drive unit 4.

[0087] The rotary guide member 31 has two radially opposite sides with grooves 31a extending in the front-back direction as indicated by arrows A1 and A2 along the axial direction of the screwdriver bit 2. The rotary guide member 31 passes radially through the retaining member 30, and connecting members 30b protruding from both sides of the retaining member 30 enter the grooves 31a, thereby connecting with the retaining member 30 via the connecting members 30b.

[0088] The retaining component 30 has a through hole perpendicular to the rotation direction of the screwdriver bit 2. A connecting component 30b is inserted into this hole and secured by a pin 30f. The connecting component 30b is a cylindrical component with an elongated oval cross-section.

[0089] The long side of the elongated oval shape of the connecting member 30b is along the direction of the extension of the groove 31a, which is parallel to the axial direction of the screwdriver bit 2 indicated by arrows A1 and A2. The short side of the elongated oval shape is orthogonal to the direction of extension of the groove 31a, as indicated by arrows B1 and B2, that is, along the rotation direction of the rotation guide member 31. Furthermore, the width of the short side of the elongated oval shape of the connecting member 30b, that is, the width along the rotation direction of the rotation guide member 31, is configured to be slightly smaller than the width of the groove 31a along that direction.

[0090] Thus, the connecting member 30b entering the groove 31a is supported in the groove 31a in a manner that allows it to move axially along the rotational guide member 31. Furthermore, the movement of the connecting member 30b relative to the rotational guide member 31 in the rotational direction is restricted between one side and the other side of the groove 31a along its extending direction. Therefore, the connecting member 30b, by means of the rotation of the rotational guide member 31, is pushed by one side or the other side of the groove 31a according to the rotational direction of the rotational guide member 31, and receives a circumferential force from the rotational guide member 31 in the rotational direction.

[0091] Therefore, when the rotary guide member 31 rotates, the connecting member 30b is pushed by the groove 31a of the rotary guide member 31, thereby keeping the member 30 rotating together with the rotary guide member 31. In addition, the connecting member 30b is guided by the groove 31a of the rotary guide member 31, keeping the member 30 moving in the front-back direction along the axial direction of the screwdriver bit 2.

[0092] The moving member 32 is an example of a transmission member, comprising: a first moving member 32a, which rotates together with the holding member 30 to move the holding member 30 in the front-back direction along the rotation guide member 31; a second moving member 32c, which is supported on the first moving member 32a via a bearing 32b and pushes the first moving member 32a via the bearing 32b; and a buffer member 32d, which is mounted on the rear side of the second moving member 32c.

[0093] The inner diameter of the first moving member 32a is slightly larger than the outer diameter of the rotary guide member 31, and it is constructed of, for example, a cylindrical member that enters the outer side of the rotary guide member 31. The first moving member 32a is connected to the retaining member 30 via a connecting member 30b protruding from the groove 31a of the rotary guide member 31, and is thus supported to be movable along the axial direction of the rotary guide member 31.

[0094] Bearing 32b is an example of a bearing, inserted between the outer periphery of the first moving member 32a and the inner periphery of the second moving member 32c. The first moving member 32a constitutes an inner ring retaining member for retaining the inner ring of bearing 32b, and the second moving member 32c constitutes an outer ring retaining member for retaining the outer ring of bearing 32b. The inner ring of bearing 32b is supported on the outer periphery of the first moving member 32a in a manner that prevents movement in the rotational direction and axial direction, and the outer ring is supported on the inner periphery of the second moving member 32c in a manner that prevents movement in the rotational direction and axial direction.

[0095] Thus, the second moving member 32c is connected to the first moving member 32a via the bearing 32b while its movement in the forward and backward direction along the axial direction is restricted. Furthermore, the second moving member 32c rotatably supports the first moving member 32a via the bearing 32b.

[0096] Therefore, the first moving member 32a is pushed by the second moving member 32c via the bearing 32b by the movement of the second moving member 32c in the forward-backward direction along the axial direction, and moves together with the second moving member 32c in the forward-backward direction along the axial direction. In addition, the first moving member 32a can rotate relative to the second moving member 32c, while the second moving member 32c does not rotate relative to the rotation guide member 31.

[0097] In this example, the force-applying component 33 is a helical spring located outside the rotation guide component 31. It enters between the front frame 10b, which is located on the front side of the housing 10a of the tool body 10, and the second moving component 32c of the moving component 32, and abuts against the spring seat 32f, which is configured to contact the end face of the outer ring of the bearing 32b. The force-applying component 33 is compressed by the movement of the moving component 32 in the forward direction indicated by arrow A1, and a force is applied to the moving component 32 to push it in the rearward direction indicated by arrow A2.

[0098] The first drive unit 4 includes a bit rotation motor 40 and a reducer 41, both electrically driven by a battery 12. The bit rotation motor 40 is an example of a motor or a first motor. The shaft 40a of the bit rotation motor 40 is connected to the reducer 41, and the shaft 41a of the reducer 41 is connected to the rotation guide member 31. The first drive unit 4 utilizes a planetary gear structure for the reducer 41. The bit rotation motor 40, the rotation guide member 31, the holding member 30, and the screwdriver bit 2 held in the holding member 30 are arranged coaxially.

[0099] The first drive unit 4 has a bit rotary motor 40 and a reducer 41 mounted on a metal rear frame 10c located at the rear of the housing 10a of the tool body 10. The shaft 41a of the reducer 41 is supported on the rear frame 10c via a bearing 42. The rear end of the rotation guide member 31 is connected to the shaft 41a of the reducer 41, which is supported on the rear frame 10c via a bearing 42. Thus, the rotation guide member 31 is rotatably supported via a bearing 42, which is an example of a bearing.

[0100] The bit holding part 3 and the first drive part 4 are assembled into one unit by connecting the front frame 10b and the rear frame 10c through a connecting part 10d extending in the front-rear direction. The front frame 10b is fixed to the housing 10a of the tool body 10 by screws 10e.

[0101] Furthermore, the front end of the rotating guide member 31 of the bit holder 3 is supported by a bearing 34a on a front frame 10b fixed to the front of the housing 10a of the tool body 10, and the rear end of the rotating guide member 31 is supported by a shaft 41a of the reducer 41 and a bearing 42 on a rear frame 10c fixed to the rear of the housing 10a. Therefore, the rotating guide member 31 of the bit holder 3 is rotatably supported on the tool body 10.

[0102] Thus, the first drive unit 4 rotates the rotation guide member 31 via the bit rotation motor 40. When the rotation guide member 31 rotates, the connecting member 30b is pushed by the groove 31a of the rotation guide member 31, thereby keeping the retaining member 30 of the screwdriver bit 2 rotating together with the rotation guide member 31.

[0103] In the bit holding part 3, a guide member 32g is provided in the second moving member 32c. A pair of guide wall parts 10g are provided in the connecting member 10d at a distance slightly larger than the diameter of the guide member 32g. The guide member 32g enters between the pair of guide wall parts 10g, so that the pair of guide wall parts 10g are opposite to the circumferential surface of the guide member 32g.

[0104] Thus, guided by the connecting member 10d via the guide member 32g, the second moving member 32c is able to move in the forward and backward directions indicated by arrows A1 and A2 along the axis of the screwdriver bit 2, and the rotation of the second moving member 32c following the rotation of the rotating guide member 31 is restricted.

[0105] Figure 6A and Figure 6B This is a top sectional view showing an example of the internal structure of the fastening tool according to this embodiment, detailing the second drive unit 5. Next, the second drive unit 5 will be described with reference to the figures.

[0106] The second drive unit 5 includes a bit-moving motor 50 and a reducer 51, both electrically driven by a battery 12. The bit-moving motor 50 is an example of a motor or a second motor. The shaft 50a of the bit-moving motor 50 is connected to the reducer 51, and the shaft 51a of the reducer 51 is connected to a pulley 52, which serves as a transmission component. The pulley 52 of the second drive unit 5 is supported on the tool body 10 via a bearing 53. The shaft 50a of the bit-moving motor 50 of the second drive unit 5 is arranged along the extending direction of the handle 11.

[0107] In the second drive unit 5, one end of a linear wire 54, which serves as a transmission component, is connected to a pulley 52. ​​As the pulley 52 rotates, the wire 54 is wound onto the pulley 52. ​​In addition, the other end of the wire 54 is connected to the wire connection portion 32h of the second moving member 32c provided on the moving member 32.

[0108] Therefore, the second drive unit 5 rotates the pulley 52 via the bit movement motor 50, winding the wire 54, thereby causing the second moving member 32c to move forward in the direction indicated by arrow A1. In the bit holding unit 3, the second moving member 32c moves forward, pushing the first moving member 32a via the bearing 32b, causing the first moving member 32a and the second moving member 32c to move together in the forward direction along the axial direction. The first moving member 32a moves forward, and the holding member 30, which is connected to the first moving member 32a via the connecting member 30b, moves forward, causing the screwdriver bit 2 held by the holding member 30 to move in the forward direction indicated by arrow A1.

[0109] The second drive unit 5 is positioned offset to one side from approximately the center in the left-right direction of the fastening tool 1, with the tangential direction of the portion on the pulley 52 where the wire 54 is wound along the extending direction of the rotation guide member 31. That is, the center of the pulley 52, in this example, is the shaft 50a of the bit movement motor 50, offset to one side relative to the rotation guide member 31, and when viewed from the axial direction of the pulley 52, the portion 52a on the pulley 52 where the wire 54 is wound overlaps with the rotation guide member 31.

[0110] In addition, such as Figure 6A , Figure 6B As shown, the wire 54 between the pulley 52 and the second moving part 32c is parallel to the axial direction of the rotation guide part 31 in the radial direction of the pulley 52, and as... Figure 1A As shown, the pulley 52 and the like are also arranged parallel to the axis of the rotation guide member 31 in the axial direction of the bit moving motor 50, which is radially orthogonal to the pulley 52.

[0111] Furthermore, when the wire 54 is wound around the pulley 52, the distance from the center of the pulley 52 to the wire 54 varies depending on the number of windings, thus the amount of movement of the screwdriver bit 2 changes when the pulley 52 rotates one revolution. In addition, the angle between the direction in which the wire 54 extends between the pulley 52 and the second moving member 32c and the direction of movement of the screwdriver bit 2 along the axial direction of the rotation guide member 31 changes.

[0112] Therefore, the diameter of the pulley 52 is set such that the rotation amount α of the pulley 52 required to move the screwdriver bit 2 by a predetermined amount is less than 360°.

[0113] Therefore, in order to move the screwdriver bit 2 by a predetermined amount, during the action of the pulley 52 winding the wire 54, such as Figure 6B As shown, the wire 54 will not overlap and wrap around the pulley 52, which can suppress inaccurate movement of the screwdriver bit 2. In addition, it can suppress changes in the parallelism between the direction in which the wire 54 extends between the pulley 52 and the second moving member 32c and the direction of movement of the screwdriver bit 2 along the axial direction of the rotation guide member 31.

[0114] Therefore, the relationship between the rotation speed of the bit moving motor 50 and the amount of movement of the holding member 30 is one-to-one throughout the entire movable range of the holding member 30. By controlling the rotation speed of the bit moving motor 50, the amount of movement of the holding member 30 along the axial direction of the rotation guide member 31 can be controlled. That is, by controlling the rotation speed of the bit moving motor 50, the amount of movement of the screwdriver bit 2 mounted on the holding member 30 can be controlled.

[0115] Furthermore, regardless of the amount of wire 54 wound, the tension applied to the wire 54 is always parallel to the direction of movement of the screwdriver bit 2 along the axial direction of the rotation guide member 31, which can suppress the movement of the screwdriver bit 2 and reduce the efficiency of force transmission for pushing the screw 200 via the screwdriver bit 2.

[0116] As a result, the wire 54 between the pulley 52 and the second moving member 32c extends in a straight line along the moving direction of the moving member 32, which suppresses the increase in load when the wire 54 is wound by the pulley 52 and the increase in load when the wire 54 is pulled out from the pulley 52.

[0117] Furthermore, since the wire 54 is flexible enough to be wound around the pulley 52, it is impossible to push the second moving member 32c to move the moving member 32 backward. Therefore, a force-applying member 33 is provided, which is compressed by the moving member 32 moving in the forward direction as shown by arrow A1, and applies a force to the moving member 32 to push it in the rearward direction as shown by arrow A2. Thus, by using the structure in which the screwdriver bit 2 is advanced by winding the wire 54 around the pulley 52, the screwdriver bit 2 can be retracted after it has advanced.

[0118] In addition, the retaining member 30 that holds the screwdriver bit 2 is supported in a manner that allows it to move in the front-back direction relative to the rotating guide member 31 by engaging with the connecting member 30b provided in the retaining member 30 and the slot 31a provided in the rotating guide member 31, and rotates together with the rotating guide member 31.

[0119] Therefore, by configuring the bit rotation motor 40, the rotation guide member 31, and the holding member 30, and the screwdriver bit 2 held in the holding member 30 on the same axis, it is possible to achieve a structure that allows the screwdriver bit 2 to rotate and move in the front-back direction without moving the bit rotation motor 40 in the front-back direction.

[0120] Furthermore, in a structure in which the bit rotary motor 40 and the screwdriver bit 2 are arranged coaxially, a structure can be considered that uses a feed screw to convert the rotational motion of the bit rotary motor 40 into the forward and backward movement of the screwdriver bit 2.

[0121] However, in the structure that utilizes the feed screw, the forward distance of the screwdriver bit 2 per motor revolution cannot be large. Therefore, even if the motor speed is increased, it is difficult to speed up the movement of the screwdriver bit 2.

[0122] In fastening tool 1, in order to shorten the time it takes to press the screw 200 onto the object to be fastened with the screwdriver bit 2, it is necessary to speed up the movement of the screwdriver bit 2. However, in a structure that utilizes a feed screw, it is difficult to shorten the time it takes to press the screw 200 onto the object to be fastened with the screwdriver bit 2.

[0123] In contrast, in a structure where the retaining member 30 holding the screwdriver bit 2 is supported in a manner that allows it to move in the front-rear direction relative to the rotation guide member 31, and the second drive unit 5 rotates the pulley 52 to wind the wire 54, causing the retaining member 30 to move in the forward direction, the moving speed of the screwdriver bit 2 can be increased according to the rotational speed of the bit moving motor 50. Therefore, the time required to push the screw 200 onto the object to be fastened using the screwdriver bit 2 can be shortened.

[0124] Figure 7A , Figure 7B This is a cross-sectional view showing an example of a disassembly and assembly retention mechanism. Figure 8A , Figure 8B This is a perspective view showing an example of a disassembly and assembly retention mechanism, illustrating the details of the disassembly and assembly retention mechanism 30c. The disassembly and assembly retention mechanism 30c will now be described with reference to the figures.

[0125] The disassembly and assembly retaining mechanism 30c includes a ball 30d protruding from the opening 30a and a spring 30e that applies force to the ball 30d in the direction of its protrusion into the opening 30a. The spring 30e is a ring-shaped leaf spring and is fitted into the outer periphery of the retaining member 30.

[0126] When the insertion part 20 of the screwdriver bit 2 is inserted into the opening 30a of the retaining member 30, the disassembly and assembly retaining mechanism 30c causes the ball 30d, which is pushed by the insertion part 20, to deform the spring 30e in the direction that increases the diameter of the annular spring 30e, while retracting towards the outer periphery of the retaining member 30.

[0127] When the insertion portion 20 of the screwdriver bit 2 is inserted into the opening 30a of the retaining member 30 until the groove 20a formed on the outer periphery of the insertion portion 20 is positioned opposite the ball 30d, the ball 30d, which is stressed by the spring 30e, is engaged in the groove 20a. This prevents the screwdriver bit 2 from being accidentally pulled out of the retaining member 30.

[0128] Furthermore, when a predetermined force or more is applied in the direction of pulling the screwdriver bit 2 out of the retaining member 30, the spring 30e is deformed in the direction of increasing the diameter of the annular spring 30e, and the ball 30d is retracted, thereby enabling the screwdriver bit 2 to be pulled out of the retaining member 30.

[0129] During the insertion and removal of the screwdriver bit 2's insertion portion 20 relative to the opening 30a of the retaining member 30, the ball 30d retracts towards the outer periphery of the retaining member 30. Therefore, space is required for the ball 30d to retract at the outer periphery of the retaining member 30. On the other hand, when the retaining member 30 is inserted into the interior of the cylindrical rotation guide member 31, space for the ball 30d to retract cannot be guaranteed between the outer periphery of the retaining member 30 and the inner periphery of the rotation guide member 31.

[0130] Furthermore, in order to ensure space for the ball 30d to retract between the outer periphery of the retaining member 30 and the inner periphery of the rotating guide member 31, if the diameter difference between the retaining member 30 and the rotating guide member 31 is set, the outer diameter of the retaining member 30 cannot be reduced since the radial dimension of the screwdriver bit 2 is already determined. Therefore, the outer diameter of the rotating guide member 31 needs to be increased. As a result, the device becomes larger.

[0131] In contrast, the rotary guide member 31 is provided with a groove 31a for the guide connecting member 30b. The groove 31a extends through the inner circumference of the rotary guide member 31 to the outer circumference and extends along the axial direction of the rotary guide member 31.

[0132] Therefore, in the disassembly and assembly retaining mechanism 30c, the ball 30d is positioned in tandem with the groove 31a of the rotary guide member 31. That is, the connecting member 30b of the retaining member 30 and the ball 30d of the disassembly and assembly retaining mechanism 30c are coaxially arranged along the axial direction of the rotary guide member 31. Thus, in either the rotation of the rotary guide member 31 and the retaining member 30, or the axial movement of the retaining member 30 relative to the rotary guide member 31, the ball 30d is exposed in the groove 31a of the rotary guide member 31.

[0133] Therefore, by using the insertion and removal action of the screwdriver bit 2's insertion portion 20 relative to the opening 30a of the retaining member 30, the ball 30d, which retracts towards the outer periphery of the retaining member 30, enters the groove 31a of the rotation guide member 31.

[0134] Therefore, by maintaining the structure of the component 30 inserted into the interior of the cylindrical rotary guide component 31, space can be ensured for the ball 30d of the disassembly and assembly retaining mechanism 30c to retract. In addition, by using the groove 31a into which the connecting component 30b enters as a space for the ball 30d to retract, the area of ​​the opening provided in the rotary guide component 31 can be suppressed, thus ensuring strength.

[0135] Furthermore, by ensuring space for the ball 30d to retract between the outer periphery of the retaining member 30 and the inner periphery of the rotating guide member 31 without increasing the diameter difference between the retaining member 30 and the rotating guide member 31, the enlargement of the device can be suppressed.

[0136] Figure 9 This is a perspective view showing an example of the screw feed section and machine head 8 of this embodiment, showing details of the screw feed section 7 and the machine head 8. Next, the screw feed section 7 and the machine head 8 will be described with reference to the figures.

[0137] The screw feed unit 7 includes a screw feed motor 70, a pinion 71 mounted on the shaft of the screw feed motor 70 via a reducer, a rack 72 meshing with the pinion 71, and a locking part 73 connected to the rack 72 and engaging with a connecting screw fed from the screw storage unit 6.

[0138] The rack 72 of the screw feed unit 7 is movably supported in the vertical direction along the feed direction of the connecting screw. The screw feed unit 7 is fed by the screw feed motor 70 rotating forward and backward, and the engaging part 73 that engages with the connecting screw moves in the vertical direction.

[0139] The head unit 8 includes: an injection passage 80 through which screws 200 are supplied via a screw feed section 7 and through which screwdriver bits 2 pass; a contact member 81 having an injection outlet 81a communicating with the injection passage 80 and contacting the object to be fastened; a contact arm 82 that moves in a front-rear direction in conjunction with the contact member 81; and an adjustment section 83 that limits the amount of movement of the contact arm 82. Additionally, the head unit 8 includes a cover member 88 that can be opened and closed to cover the path through which the screws 200 pass from the screw storage section 6 to the injection passage 80.

[0140] The fastening tool 1 assembles the components constituting the injection passage 80, the contact member 81, and the contact arm 82 to form the head 8, and fixes it to the front frame 10b and the head body 10f constituting the tool body 10. In addition, the fastening tool 1 has a contact switch 84 that is actuated by being pushed by the contact arm 82.

[0141] At the machine head 8, the contact member 81 is supported in a manner that allows it to move in the front-back direction as indicated by arrows A1 and A2, and the contact arm 82 moves in the front-back direction in conjunction with the contact member 81. At the machine head 8, the contact member 81 is subjected to a force in the forward direction by a force-applying member (not shown), and the contact member 81, which has been pushed backward by the fastening object, is subjected to a force in the forward direction by the force-applying member.

[0142] At the machine head 8, the contact member 81 is pressed by the object being fastened, causing the contact arm 82 to move backward. The adjustment unit 83 adjusts the amount of movement of the contact arm 82 until the contact switch unit 84 is activated. The contact switch unit 84 switches between active and inactive states by being pushed by the contact arm 82. In this example, the state where the contact switch unit 84 is inactive when not pushed by the contact arm 82 is defined as the open state of the contact switch unit 84, and the state where the contact switch unit 84 is activated when pushed by the contact arm 82 is defined as the closed state of the contact switch unit 84.

[0143] Next, referring to the figures, the structure related to the control and operation of the fastening tool 1 will be described. The fastening tool 1 includes a trigger 9 that receives operation and a trigger switch 90 that is actuated by the operation of the trigger 9. The trigger 9 is located on the front side of the handle 11 and is configured to be operated by the fingers of the hand holding the handle 11. The trigger switch 90 is actuated by being pushed by the trigger 9.

[0144] The trigger switch 90 switches between active and inactive states by being pushed by the trigger 9. In this example, the state in which the trigger 9 is not operated and the trigger switch 90 is not pushed by the trigger 9 and is inactive is defined as the trigger switch 90 being open. The state in which the trigger 9 is operated and the trigger switch 90 is pushed by the trigger 9 and is inactive is defined as the trigger switch 90 being on.

[0145] The fastening tool 1 includes a control unit 100, which controls the first drive unit 4, the second drive unit 5, and the screw feed unit 7 based on the outputs of the trigger switch unit 90, which is operated by the trigger 9, and the contact switch unit 84, which is pushed by the contact member 81.

[0146] The control unit 100 is composed of a substrate on which various electronic components are mounted. Between the screw storage unit 6 and the handle 11, a substrate storage unit 111 is provided on the back side of the screw storage unit 6.

[0147] In power tools that are used with the handle held by hand, a storage section for consumables such as screws is located at the front of the handle. Furthermore, space is required between the handle and the storage section for the fingers to fit in order to grip the handle.

[0148] Therefore, the fastening tool 1 utilizes the space between the screw storage part 6 and the handle 11 to provide a substrate storage part 111 on the back side of the screw storage part 6.

[0149] In power tools used by holding the handle by hand, a structure has been proposed in which a battery is installed at the bottom of the handle and a substrate is placed between the handle and the battery. With such a structure, the vertical dimension of the power tool along the extension direction of the handle is increased.

[0150] In contrast, by providing a substrate storage portion 111 on the back side of the screw storage portion 6, it is possible to suppress the enlargement of the fastening tool 1 in the vertical direction along the extension direction of the handle 11. Furthermore, since the screw storage portion 6 houses the connecting screw wound into a spiral shape, the surface of the screw storage portion 6 facing the handle 11 is approximately circular. This prevents the fastening tool 1 from becoming too large and ensures the volume of the substrate storage portion 111.

[0151] Figures 10A to 10C This is a perspective view from the rear, showing an example of the fastening tool according to this embodiment. Figure 11 This is a perspective view showing an example of the setting unit, illustrating details of the setting unit 110. Next, the setting unit 110 will be described with reference to the figures.

[0152] The fastening tool 1 includes a second drive unit 5 that moves the screwdriver bit 2 in the forward and backward direction along the axial direction. The second drive unit 5 is driven by a bit movement motor 50 and is a structure in which a moving member 32 connected to a pulley 52 that is driven to rotate by the bit movement motor 50 is connected to a wire 54 and a holding member 30 connected to the moving member 32 moves along the rotation guide member 31 in the forward direction along the axial direction of the screwdriver bit 2.

[0153] Therefore, by controlling the rotation speed of the bit movement motor 50, the amount of movement (forward movement) of the screwdriver bit 2 can be controlled. That is, by rotating the bit movement motor 50 in conjunction with the rotation of the bit rotation motor 40 that rotates the screwdriver bit 2 in the direction of tightening the screw 200, the forward movement of the screwdriver bit 2, which follows the screw 200 as it is tightened, can be controlled by the rotation speed of the bit movement motor 50, thereby controlling the axial stop position of the screwdriver bit 2.

[0154] Therefore, the fastening tool 1 includes a setting section 110 for setting the advance amount of the screwdriver bit 2. The setting section 110 is an example of a setting unit, configured to allow selection of any setting value from a plurality of setting values, or to allow stepless selection of any setting value.

[0155] In this example, the setting unit 110 uses an operation unit 110a composed of buttons to select the setting value. Alternatively, the operation unit 110a can also be a structure where the setting value is selected by a rotary dial. Furthermore, the setting unit 110 can also display the selected setting value by using a label, marking, or a display unit 110b such as an LED to indicate the current value, so that the operator can easily grasp the current setting value.

[0156] The setting part 110 is provided in the base plate storage part 111 provided on the back side of the screw storage part 6, and is respectively provided on the left and right sides of the surface opposite to the handle 11.

[0157] Therefore, when observing the fastening tool 1 from the rear, the setting section 110 can be visually confirmed from the left and right sides of the handle 11.

[0158] When using the screwdriver by holding the handle 11, the side of the screw storage section 6 opposite to the handle 11 faces the operator holding the fastening tool 1. Therefore, in the base plate storage section 111 located on the back side of the screw storage section 6, the display section 110b provided on the side opposite to the handle 11 is easily visible. This reduces the possibility of the operator missing the display. Furthermore, the information displayed on the display section 110b includes, in addition to the screw depth setting determined by the advance amount of the screwdriver bit 2, the power on / off status, the operating mode selected from various selectable operating modes, the presence or absence of a screw, the remaining screw weight, and the presence or absence of any abnormalities.

[0159] Furthermore, when using the handle 11 by hand, the operation section 110a, including buttons on the setting section 110, is easily visible. Therefore, while holding the handle 11 with one hand, the operation section 110a can be visually inspected while the other hand is used to operate it, allowing for reliable operation.

[0160] Furthermore, the substrate that constitutes the control unit 100 is housed in the substrate storage section 111. In this substrate, by mounting switches or the like that constituting the operation section 110a and lamps or the like that constituting the display section 110b on the side opposite to the handle 11, the substrate that is different from the control unit 100 and is used for the setting section 110 can be omitted.

[0161] Figure 12 This is a block diagram illustrating an example of the fastening tool according to this embodiment. As described above, the fastening tool 1 includes a second drive unit 5 that moves the screwdriver bit 2 in a forward-backward direction along the axial direction. The second drive unit 5 is driven by a bit movement motor 50. A holding member 30 on which the screwdriver bit 2 is mounted is connected to a moving member 32, which is connected to a pulley 52 that is driven to rotate by the bit movement motor 50 via a wire 54. Furthermore, the holding member 30 and the moving member 32 are configured to move along the rotation guide member 31 in a forward direction along the axial direction of the screwdriver bit 2.

[0162] Therefore, by controlling the rotation speed of the bit movement motor 50, the control unit 100 can control the amount of movement (forward movement) of the screwdriver bit 2. That is, in conjunction with the rotation of the bit rotation motor 40 that rotates the screwdriver bit 2 in the direction of tightening the screw 200, by rotating the bit movement motor 50, the forward movement of the screwdriver bit 2, which follows the screw 200 as it is tightened, can be controlled by the rotation speed of the bit movement motor 50, thereby controlling the axial stop position of the screwdriver bit 2.

[0163] Furthermore, the control unit 100 sets the rotation speed of the bit movement motor 50, which determines the forward advance of the screwdriver bit 2, using the setting unit 110. Moreover, the control unit 100 controls the presence or absence of drive for the bit movement motor 50 of the second drive unit 5 and the bit rotation motor 40 of the first drive unit 4, based on combinations of the on / off states of the contact switch unit 84 and the trigger switch unit 90.

[0164] <Example of the operation of the fastening tool in this embodiment>

[0165] Figure 13A This is a side sectional view illustrating an example of the operation of the fastening tool according to this embodiment. Figure 13B This is a top sectional view illustrating an example of the operation of the fastening tool according to this embodiment. Figure 14 The flowchart shows an example of the operation of the fastening tool according to this embodiment. Next, the fastening operation of the fastening tool according to this embodiment will be explained with reference to the figures.

[0166] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0167] Control unit 100 Figure 14 In step SA1, based on the setting value selected by the setting unit 110, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SA2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SA3, when the trigger switch 90 is turned on, the bit rotation motor 40 of the first drive unit 4 is driven in step SA4, and the bit movement motor 50 of the second drive unit 5 is driven in step SA5.

[0168] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​By winding the wire 54 onto the pulley 52, the second moving part 32c, connected to the wire 54, is guided by the rotation guide part 31 to move forward in the axial direction. As the second moving part 32c moves forward, the first moving part 32a is pushed by the second moving part 32c via the bearing 32b, and together with the second moving part 32c, compresses the force-applying part 33 while moving forward in the axial direction.

[0169] When the first moving part 32a moves forward, the connecting part 30b of the holding part 30, which is connected to the first moving part 32a via the connecting part 30b, is guided by the groove 31a of the rotation guide part 31, thereby moving the holding part 30 forward along the axial direction of the screwdriver bit 2.

[0170] As a result, the screwdriver bit 2 held in the holding part 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0171] Furthermore, when the bit rotation motor 40 is driven to rotate in the positive direction, the rotation guide member 31 rotates in the positive direction. When the rotation guide member 31 rotates in the positive direction, the connecting member 30b connected to the holding member 30 is pushed by the groove 31a of the rotation guide member 31, thereby keeping the member 30 and the rotation guide member 31 rotating together.

[0172] Therefore, the screwdriver bit 2 held in the holding member 30 rotates the screw 200 in the positive direction (clockwise) and screws it into the object to be fastened. The control unit 100, in conjunction with the operation of rotating the screwdriver bit 2 via the first drive unit 4 to screw the screw into the object, moves the screwdriver bit 2 forward via the second drive unit 5 according to the load applied to the bit rotation motor 40, the rotation speed of the bit rotation motor 40, the load applied to the bit movement motor 50, and the rotation speed of the bit movement motor 50, so that the screwdriver bit 2 follows the screw being screwed into the object. In this embodiment, the load applied to the bit rotation motor 40, etc., refers to the force based on resistance including the frictional force generated between the screw 200 and the object when the screw 200 is screwed into the object.

[0173] In step SA6, the control unit 100 determines that the rotational speed of the bit movement motor 50 has reached the set value selected by the setting unit 110. Figure 13A , Figure 13B When the front end of the screwdriver bit 2 reaches the set end position P2, the drive of the bit rotation motor 40 is stopped in step SA7, and after the bit movement motor 50 is stopped from rotating in the positive direction in step SA8, the bit movement motor 50 is reversed in step SA9.

[0174] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​By pulling the wire 54 out of the pulley 52, the second moving part 32c moves forward, thereby extending the compressed force-applying part 33 and pushing the second moving part 32c backward.

[0175] The second moving part 32c is pushed rearward by the force-applying part 33, and thus guided by the rotation guide part 31 to move in the rearward direction along the axial direction. When the second moving part 32c moves rearward, the first moving part 32a is pulled by the second moving part 32c via the bearing 32b, and moves together with the second moving part 32c in the rearward direction along the axial direction.

[0176] When the first moving part 32a moves in the rearward direction, the connecting part 30b of the holding part 30, which is connected to the first moving part 32a via the connecting part 30b, is guided by the groove 31a of the rotation guide part 31, thereby the holding part 30 moves in the rearward direction along the axial direction of the screwdriver bit 2.

[0177] In step SA10, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SA11, the reverse rotation of the bit moving motor 50 is stopped.

[0178] Furthermore, the moving part 32 has a cushioning part 32d made of rubber or the like on the rear side of the second moving part 32c. This prevents the second moving part 32c from directly contacting the rear frame 10c during its rearward movement, thus suppressing noise generation and damage. When the trigger switch 90 is off, the control unit 100 rotates the screw feed motor 70 in one direction, causing the engaging part 73 to descend. When the engaging part 73 descends to the position where it engages with the next screw 200, the control unit 100 reverses the screw feed motor 70, causing the engaging part 73 to rise and supplying the next screw 200 to the injection passage 80.

[0179] Figures 15A-15C This is a cross-sectional view showing the tightened state of the screws. Figure 15A This refers to a state where the head 201 of the screw 200 does not rise from or sink into the surface of the object 202 being fastened, a state known as coplanarity. Figure 15B This indicates that the head 201 of the screw 200 is raised from the object 202 being fastened. Figure 15C This indicates the state in which the head 201 of the screw 200 is embedded in the object 202 being fastened.

[0180] When the fastening tool 1 reaches the end position P2 at the front end of the screwdriver bit 2, if the screw 200 is a countersunk screw, as follows: Figure 15AAs shown, preferably, the advance amount of the screwdriver bit 2 is set such that the surface of the head 201 of the screw 200 is in a so-called coplanar state with the surface of the object being fastened 202. Furthermore, the screw 200 is not limited to a countersunk screw; if it is a pan head screw, a terminal screw, a truss screw, etc., then preferably, the advance amount of the screwdriver bit 2 is set in such a way that the seat surface of the head 201 of the screw 200 contacts the surface of the object being fastened 202, and the head 201 of the screw 200 does not become lifted off the object being fastened 202.

[0181] When the front end of the screwdriver bit 2 reaches the end position P2, the head 201 of the screw 200... Figure 15B When the screwdriver bit 2 is in a state where it is lifted from the fastened object 202, the setting unit 110 sets the movement amount (forward amount) of the screwdriver bit 2. The forward amount of the screwdriver bit 2 is increased by increasing the rotation speed (rotation amount) of the bit movement motor 50, causing the operation end position P2 to advance. On the other hand, at the head 201 of the screw 200... Figure 15C When the screwdriver bit 2 is embedded in the fastening object 202 as shown, the setting unit 110 sets the movement amount (forward amount) of the screwdriver bit 2. By reducing the rotation speed of the screwdriver bit moving motor 50, the forward amount of the screwdriver bit 2 is reduced, and the operation end position P2 is moved back.

[0182] As described above, the amount of movement (forward movement) of the screwdriver bit 2 is determined by the rotation speed of the bit movement motor 50. Furthermore, starting from the initial position of the screwdriver bit 2, i.e., the standby position P1, the bit movement motor 50 is rotated to the number of revolutions set by the setting unit 110, and then the bit movement motor 50 is stopped or reversed, thereby controlling the operation to the end position P2. Therefore, the screwing depth can be adjusted.

[0183] Thus, in order to advance the front end of the screwdriver bit 2 held in the holding member 30 by a predetermined amount based on the rotation speed of the bit movement motor 50, using the predetermined standby position P1 as a reference, the standby positions of the holding member 30 on which the screwdriver bit 2 is mounted and the moving member 32 that moves the holding member 30 are set. The action of setting the standby positions of the holding member 30 and the moving member 32 is called the first initialization action.

[0184] Then, before the driving and tightening actions begin, the holding member 30 and the moving member 32 are moved to the set standby position. Using the standby position as a reference, the position of the holding member 30 and the moving member 32 is controlled by the rotation speed of the bit movement motor 50. Then, the holding member 30 and the moving member 32 are advanced from the set standby position to a predetermined movement amount (advance amount) to perform the tightening action. The action of moving the holding member 30 and the moving member 32 to the standby position set in the first initialization action is called the second initialization action.

[0185] As a unit for setting the standby position of the holding member 30 and the moving member 32 in the first initialization operation, a unit that uses a sensor or a unit that uses the maximum position of the range of forward and backward movement of the holding member 30 and the moving member 32 as a reference is considered. When using a sensor, the sensor's detection position or the position that has moved a predetermined amount from the detection position is set as the standby position.

[0186] In addition, when using the maximum position of the range that can move back and forth, the position in which the holding member 30 and the moving member 32 have moved a predetermined amount from the front position or the rear position is set as the standby position.

[0187] Figures 16A to 16D This is an explanatory diagram illustrating an example of setting the standby positions of the holding member and the moving member during the first initialization operation. Next, the operation of setting the standby positions of the holding member 30 and the moving member 32 will be explained. Furthermore, in Figures 16A to 16D The example shown is an action of setting the standby position by using the maximum position of the range that the holding member 30 and the moving member 32 can move back and forth.

[0188] like Figure 16A As shown, the control unit 100 starts from a state where the holding member 30 and the moving member 32 are in any position, and rotates the bit moving motor 50 in the positive direction. When the bit moving motor 50 rotates in the positive direction, the wire 54 is wound onto the pulley 52, thereby moving the moving member 32 and the holding member 30 connected to the moving member 32 move forward along the axis of the screwdriver bit 2 along the rotation guide member 31.

[0189] like Figure 16B As shown, when the bit moving motor 50 rotates forward until the holding member 30 and the moving member 32 move to one end position, i.e., the front end position PF, the control unit 100 stops the forward rotation of the bit moving motor 50, so that the holding member 30 and the moving member 32 move to the front end position PF.

[0190] Next, the control unit 100 rotates the bit movement motor 50 in the opposite direction. When the bit movement motor 50 reverses, the wire 54 is pulled out from the pulley 52, thereby the moving part 32 is pushed backward by the force application member 33, and the moving part 32 and the holding member 30 connected to the moving part 32 move backward along the rotation guide member 31 along the axis of the screwdriver bit 2.

[0191] like Figure 16CAs shown, when the bit moving motor 50 reverses until the holding member 30 and the moving member 32 move to the other end position, i.e., the rear end position PE, the control unit 100 stops the reverse rotation of the bit moving motor 50 and moves the holding member 30 and the moving member 32 to the rear end position PE by applying force through the force application member 33.

[0192] The control unit 100 obtains the amount of movement of the holding member 30 and the moving member 32 from the front position PF to the rear position PE as the overall distance L1. The amount of movement from the front position PF to the rear position PE is calculated from the number of revolutions of the bit moving motor 50.

[0193] The control unit 100 presets the movement amount of the holding component 30 and the moving component 32 from the standby position to the front position PF as the target movement amount L2. The control unit 100 sets the difference between the total distance L1 from the front position PF to the rear position PE and the preset target movement amount L2 as the standby position movement amount L3, and stores it. The standby position movement amount L3 is the movement amount of the holding component 30 and the moving component 32 from the rear position PE.

[0194] like Figure 16D As shown, the control unit 100 rotates the bit movement motor 50 forward, causing the holding member 30 and the moving member 32 to move forward from the rear position PE. When the control unit 100 rotates the bit movement motor 50 forward by a number of revolutions equivalent to the standby position movement amount L3, it stops the forward rotation of the bit movement motor 50, moves the holding member 30 and the moving member 32 to the standby position, and moves the front end of the screwdriver bit 2 held in the holding member 30 to the standby position P1.

[0195] Furthermore, when the holding member 30 and the moving member 32 are moved to the front position PF and the rear position PE, and when the second moving member 32c comes into contact with the buffer member 32d, it is preferable to drive at a low speed that does not affect the durability of the tool.

[0196] Figures 17A-17C This is an explanatory diagram illustrating an example of the action of moving the holding member and the moving member to the standby position during the second initialization operation. Next, the action of moving the holding member 30 and the moving member 32 to a preset standby position will be explained.

[0197] like Figure 17A As shown, the control unit 100 rotates the bit movement motor 50 in the opposite direction from a state where the holding member 30 and the moving member 32 are in any position. When the bit movement motor 50 reverses, the wire 54 is pulled out from the pulley 52, the moving member 32 is pushed backward by the force application member 33, and the moving member 32 and the holding member 30 connected to the moving member 32 move backward along the axis of the screwdriver bit 2 along the rotation guide member 31.

[0198] like Figure 17B As shown, when the bit moving motor 50 reverses until the holding member 30 and the moving member 32 move to the rear end position PE, the control unit 100 stops the reverse rotation of the bit moving motor 50 and moves the holding member 30 and the moving member 32 to the rear end position PE by applying force through the force application member 33.

[0199] like Figure 17C As shown, the control unit 100 rotates the bit movement motor 50 forward, causing the holding member 30 and the moving member 32 to move forward from the rear position PE. When the control unit 100 rotates the bit movement motor 50 forward by a number of revolutions equivalent to the standby position movement amount L3, it stops the forward rotation of the bit movement motor 50, moves the holding member 30 and the moving member 32 to the standby position, and moves the front end of the screwdriver bit 2 held in the holding member 30 to the standby position P1.

[0200] exist Figures 16A to 16D In the first initialization action described herein, the action of setting the standby position of the holding component 30 and the moving component 32 is performed at the factory, for example, without relying on the user's operation, such as when the product is shipped, and the standby position movement amount L3 is pre-stored.

[0201] On the other hand, Figures 17A-17C In the second initialization action described herein, the action of moving the holding member 30 and the moving member 32 to the standby position based on the standby position movement amount L3 is preferably performed each time the power to the fastening tool 1 is turned on in order to perform a stable fastening action.

[0202] Therefore, it is configured to select an initialization action related to the standby position of the holding member 30 and the moving member 32, namely a first initialization action and a second initialization action.

[0203] Figure 18 This is a flowchart illustrating an example of selecting the first initialization action and the second initialization action.

[0204] When in Figure 18 When power is applied in step SB1, the control unit 100 selects the initialization action to be performed in step SB2. When the control unit 100 selects to execute the first initialization action, in step SB3, the aforementioned initialization action is executed. Figures 16A to 16D The first initialization action described herein sets the standby positions of the holding component 30 and the moving component 32. When the control unit 100 selects to execute the second initialization action, the above-described initialization action is executed in step SB4. Figures 17A-17C The second initialization action described herein involves moving the holding member 30 and the moving member 32 to the standby position based on the standby position movement amount L3. After executing the second initialization action, the control unit 100, in step SB5, proceeds according to the above-described... Figure 14 The flowchart, etc., is used to perform the usual fastening actions.

[0205] As described above, in the first initialization operation, the holding member 30 and the moving member 32 are moved from the front position PF to the rear position PE at a low speed, and the overall distance L1 from the front position PF to the rear position PE is obtained. The amount of movement from the rear position PE, determined in such a way that the amount of movement from the front position PF becomes a predetermined target movement amount L2, is set as the standby position movement amount L3 and recorded in a memory on a substrate (not shown) constituting the control unit 100. This eliminates various mechanical deviations such as dimensional differences within tolerance ranges, and sets the standby position of the holding member 30 and the moving member 32 to, for example, a certain position from the front position PF.

[0206] Furthermore, in the second initialization operation, whenever the user turns on the power for use, the holding member 30 and the moving member 32 are moved from the rear position PE to the standby position according to the standby position movement amount L3, thereby minimizing the movement amount of the holding member 30 and the moving member 32. Moreover, in the second initialization operation, the second initialization operation can be performed when the front end of the screwdriver bit 2 is in the standby position P1 behind the injection passage 80, and a screw 200 has been supplied to the injection passage 80.

[0207] As described above, the amount of movement (forward movement) of the screwdriver bit 2 is determined by the rotation speed of the bit movement motor 50, starting from the standby position of the holding member 30 and the moving member 32, i.e., the standby position P1 of the screwdriver bit 2. Therefore, when there is a deviation in the standby position of the holding member 30 and the moving member 32, i.e., the standby position P1 of the screwdriver bit 2, the screwing depth set by the setting unit 110 will also be deviated.

[0208] In contrast, a second initialization action is performed each time power is applied. Starting from the standby position of component 30 and moving component 32, i.e. the standby position P1 of screwdriver bit 2, the screwdriver bit moving motor 50 is rotated at a speed set by the setting unit 110, thereby enabling accurate adjustment of the screw insertion depth.

[0209] Figure 19 This is a flowchart illustrating a modified example of the operation of the fastening tool according to this embodiment. Figure 20 This is a graph showing the relationship between the output of the contact switch and the control of the bit rotation motor and the bit movement motor. Next, referring to the graphs, other examples of the fastening operation of the fastening tool in this embodiment will be described. In this modified example, based on the output of the contact switch 84, it is detected whether the fastening tool 1 has lifted relative to the object being fastened, and the bit rotation motor 40 and the bit movement motor 50 are controlled.

[0210] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0211] Control unit 100 Figure 19 In step SC1, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110. When the contact member 81 is pressed by the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SC2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SC3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SC4, and drives the bit movement motor 50 of the second drive unit 5 in step SC5.

[0212] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0213] As a result, the screwdriver bit 2 held in the holding part 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0214] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0215] Therefore, the screwdriver bit 2 held in the holding member 30 rotates the screw 200 in the positive direction (clockwise) and screws it into the object to be fastened. The control unit 100 is linked to the operation of rotating the screwdriver bit 2 by the first drive unit 4 to screw the screw into the object to be fastened. According to the load applied to the bit rotation motor 40, the rotation speed of the bit rotation motor 40, the load applied to the bit movement motor 50, the rotation speed of the bit movement motor 50, etc., the second drive unit 5 moves the screwdriver bit 2 forward, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0216] In step SC6, the control unit 100 determines that the rotation speed of the bit movement motor 50 has become the set value selected by the setting unit 110, and when the front end of the screwdriver bit 2 reaches the set end position P2, the control unit 100 stops the drive of the bit movement motor 50 in step SC7.

[0217] When the control unit 100 stops the drive of the bit movement motor 50 in step SC7, it determines whether the contact switch 84 is turned on in step SC8. When the contact switch 84 is turned on, the control unit 100 determines that the fastening tool 1 has not floated away from the object being fastened. In order to end the fastening operation, it stops the rotation of the bit rotation motor 40 in the positive direction in step SC9 and reverses the bit movement motor 50 in step SC10.

[0218] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0219] In step SC11, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SC12, the reverse rotation of the bit moving motor 50 is stopped.

[0220] In step SC8, if the contact switch 84 is disconnected, the control unit 100 determines that the fastening tool 1 is floating away from the object being fastened, and continues to drive the bit rotation motor 40 to rotate in the positive direction while the bit movement motor 50 is stopped.

[0221] As a result, the screwdriver bit 2 held in the holding member 30 rotates the screw 200 in the positive direction, further screwing it into the object to be fastened, thereby moving the fastening tool 1 closer to the object to be fastened. Therefore, the fastening tool 1 moves relative to the contact arm 82, and the contact switch 84 is pushed by the contact arm 82, activating the contact switch 84. When the contact switch 84 is activated, the control unit 100 performs the above-described steps SC9 to SC12 to end the fastening operation, resetting the screwdriver bit 2 to the standby position by stopping the bit rotation motor 40 and reversing the bit movement motor 50.

[0222] In addition, when the contact switch 84 is disconnected and the drive of the bit moving motor 50 is stopped, the control unit 100 performs a braking operation during the operation of rotating the bit rotating motor 40 in the positive direction to prevent the bit moving motor 50 from rotating due to external force. As a result, the holding member 30, the moving member 32 and the screwdriver bit 2 held in the holding member 30 are kept in the state of stopping at the operation end position P2.

[0223] However, even when the bit movement motor 50 is stopped, during the operation of rotating the bit rotation motor 40 in the forward direction, the fastening tool 1 is in a state where the operator applies force in the direction of pressing the object being fastened while tightening the screw 200. Therefore, even if the bit movement motor 50 is braked, due to the force applied by the operator, the holding member 30, the moving member 32, and the screwdriver bit 2 held in the holding member 30 may still move backward from the operation end position P2.

[0224] Therefore, in step SC13, the control unit 100 detects whether the bit movement motor 50 is rotating in reverse. When reverse rotation of the bit movement motor 50 is detected, the control unit returns to step SC5, causing the bit movement motor 50 to rotate forward, moving the holding member 30 and the moving member 32 forward, and returning the screwdriver bit 2 to the end position P2. Then, the forward rotation of the bit movement motor 50 is stopped, and a braking action is performed.

[0225] Furthermore, in order to switch the contact switch 84 on and off via the contact arm 82, the contact arm 82 needs to move by a predetermined amount. Therefore, as described above, in step SC8, when the contact switch 84 is detected to be off, the bit movement motor 50 is stopped, but the bit rotation motor 40 continues to rotate in the forward direction until the contact switch 84 switches from off to on. During the movement of the contact arm 82, the positions of the holding member 30 and the moving member 32 may change. Therefore, it is preferable to have a detection unit that detects the position of the contact arm 82. Alternatively, a structure in which a single motor rotates the bit holding member 3 and moves the bit holding member 3 axially can also be used, and the control unit 100 can control the timing of stopping the drive of the single motor based on whether the contact switch 84 is activated.

[0226] Figure 21 This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Figure 22A , Figure 22B This is a graph showing the relationship between the load and the control of the bit rotation motor. Next, referring to the graphs, other variations of the fastening operation of the fastening tool in this embodiment will be described. In this variation, the load applied to the bit rotation motor 40 is detected, and the bit rotation motor 40 is controlled.

[0227] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0228] Control unit 100 Figure 21In step SD1, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SD2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SD3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SD4, and drives the bit movement motor 50 of the second drive unit 5 in step SD5.

[0229] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0230] As a result, the screwdriver bit 2 held in the holding part 30 moves forward in the direction indicated by arrow A1 and engages with the screw 200 supplied to the ejection port 81a of the head 8, causing the screw 200 to move forward and press against the object to be fastened.

[0231] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0232] Therefore, the screwdriver bit 2 held in the holding member 30 rotates the screw 200 in the positive direction (clockwise) and screws it into the object to be fastened. The control unit 100 is linked to the operation of rotating the screwdriver bit 2 by the first drive unit 4 to screw the screw into the object to be fastened. According to the load applied to the bit rotation motor 40, the rotation speed of the bit rotation motor 40, the load applied to the bit movement motor 50, the rotation speed of the bit movement motor 50, etc., the second drive unit 5 moves the screwdriver bit 2 forward, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0233] In step SD6, the control unit 100 determines whether the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. When the control unit 100 determines that the rotation speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, in step SD7, the control unit 100 detects the load applied to the bit rotation motor 40. When a predetermined load is detected, in step SD8, the control unit 100 controls the bit rotation motor 40.

[0234] The rotational speed of the screwdriver bit 2 varies depending on the load applied to the screwdriver bit motor 40. If the current and voltage values ​​applied to the screwdriver bit motor 40 are the same, the higher the load applied to the screwdriver bit motor 40, the lower the rotational speed. Therefore, the control unit 100, as a change detection unit that detects the main cause of the rotational speed variation of the screwdriver bit motor 40, detects the load applied to the screwdriver bit motor 40. The lower the load applied to the screwdriver bit motor 40, the lower the voltage value applied to the screwdriver bit motor 40 and the lower the current value flowing through the screwdriver bit motor 40, etc., compared to a high load, thereby reducing the output of the screwdriver bit motor 40. For example, a threshold value can be preset as a reference for judging the load size. If the detected load applied to the screwdriver bit motor 40 is above the threshold value, control is performed by reducing the voltage value, current value, or output of the screwdriver bit motor 40, etc., and if the detected load applied to the screwdriver bit motor 40 is below the threshold value, control is performed by increasing the voltage value, current value, or output of the screwdriver bit motor 40, etc.

[0235] Therefore, when the load applied to the bit rotating motor 40 is low, by reducing the rotational speed of the bit rotating motor 40, compared to the case of a high load, it is possible to suppress the increase in rotational speed and prevent the rotational speed of the bit rotating motor 40 from differing due to the magnitude of the load applied to the bit rotating motor 40. Thus, it is possible to suppress deviations in the speed of the fastening screw 200.

[0236] In step SD6, the control unit 100 determines that the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110 and the front end of the screwdriver bit 2 has reached the set end position P2. In step SD9, the control unit 100 stops the drive of the bit rotation motor 40. After stopping the rotation of the bit movement motor 50 in the positive direction in step SD10, the control unit 100 reverses the bit movement motor 50 in step SD11.

[0237] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0238] In step SD12, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then the control unit 100 stops the reverse rotation of the bit moving motor 50 in step SD13.

[0239] In the control that reduces the output of the bit rotation motor 40, such as Figure 22A As shown, the output can also be reduced after a predetermined load is detected, so that the rotational speed becomes constant until the screwdriver bit 2 moves to the end position of the operation by the number of revolutions of the bit rotation motor 40. Additionally, as... Figure 22B As shown, the output can also be gradually reduced after a predetermined load is detected, so that the rotational speed of the bit rotation motor 40 before the screwdriver bit 2 moves to the end position of the operation becomes the target rotational speed.

[0240] Furthermore, due to fluctuations in the power supply voltage, the rotational speed of the screwdriver bit 2 varies; the lower the power supply voltage, the lower the rotational speed. Therefore, the control unit 100, as a fluctuation detection unit that detects the main cause of the rotational speed variation of the screwdriver bit rotary motor 40, detects the power supply voltage. The higher the power supply voltage, the more the output of the screwdriver bit rotary motor 40 decreases compared to the case of a low power supply voltage.

[0241] Therefore, when the power supply voltage is high, compared to when the power supply voltage is low, by reducing the rotational speed of the bit motor 40, it is possible to suppress the difference in rotational speed of the bit motor 40 due to power supply voltage fluctuations. Thus, deviations in the speed of the fastening screw 200 can be suppressed.

[0242] In addition, the control unit 100 can also set the target speed of the bit rotating motor 40, detect the speed of the bit rotating motor 40, compare the detected speed of the bit rotating motor 40 with the preset target speed of the bit rotating motor 40, and control the bit rotating motor 40 in a way that achieves the target speed.

[0243] Furthermore, reducing the rotational speed of the screwdriver bit motor 40 becomes a major reason for the decrease in the operating speed of tightening the screw onto the object. On the other hand, during the stopping process of the screwdriver bit motor 40 after the screw has been screwed into the target screw depth set by the setting unit 110, the screw is screwed into the object by rotating the screwdriver bit 2 until the rotation of the screwdriver bit motor 40 completely stops. Therefore, the faster the rotational speed of the screwdriver bit motor 40 is just before it stops, the deeper the screw is screwed into the target depth.

[0244] Thus, the main reason for the reduced quality of screw-in operation due to the difference in the rotational speed of the bit rotating motor 40 is the rotational speed of the bit rotating motor 40 when it is about to stop. Therefore, if the rotational speed of the bit rotating motor 40 becomes constant, excluding the influence of the load, when the movement amount (advance) of the holding component 30 and the moving component 32 is about to reach the target screw-in depth set by the setting unit 110, the desired effect can be obtained.

[0245] The load applied to the bit rotating motor 40 increases when the screw begins to be screwed into the object being fastened, but the load varies depending on the material of the object being fastened. Therefore, after detecting the load mentioned above, which is used to control the rotational speed of the bit rotating motor 40, the rotational speed of the bit rotating motor 40 is controlled based on the load, power supply voltage, etc., before the target screw insertion depth is reached.

[0246] Furthermore, a timing unit may be included, and the control unit 100 performs speed control of the bit rotating motor 40 based on load, power supply voltage, etc., after a predetermined time has elapsed since the start of driving (forward rotation) of the bit rotating motor 40. Additionally, a position detection unit may be included to detect the positions of the holding member 30 and the moving member 32, and after the holding member 30 and the moving member 32 reach a predetermined position, it performs speed control of the bit rotating motor 40 based on load, power supply voltage, etc. The predetermined positions of the holding member 30 and the moving member 32 for controlling the speed of the bit rotating motor 40 are set between the position of detecting the load used to control the speed of the bit rotating motor 40 and the position where the target screw insertion depth is reached.

[0247] Furthermore, in the method of setting the target speed of the bit rotary motor 40 and controlling its output, considering the influence of factors such as the length of the control implementation interval, the target screw insertion depth may be reached before the speed of the bit rotary motor 40 decreases to the target speed. Therefore, braking control of the bit rotary motor 40 can also be performed during the control period to reduce the speed of the bit rotary motor 40 to the target speed. For example, braking control of the bit rotary motor 40 can be performed when the deviation between the target speed and the detected actual speed of the bit rotary motor 40 is large, until the deviation between the actual speed and the target speed is within a specified range. When the deviation is within the specified range, control is performed to reduce the speed of the bit rotary motor 40 to the target speed.

[0248] Furthermore, if the screwdriver bit 2 disengages from the screw after reaching the target screw insertion depth, the screw will not be further screwed in even if the screwdriver bit 2 rotates. Therefore, the screwdriver bit movement motor 50 can be reversed after the screwdriver bit 2 has advanced to the target screw insertion depth, before the screwdriver bit rotation motor 40 stops rotating. Alternatively, a structure can be constructed in which a single motor rotates the screwdriver bit holder 3 and moves it axially. The control unit 100 can also detect the load applied to the single motor, the main cause of the motor's speed variation, and control the motor.

[0249] Figure 23 This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Figure 24A This is a graph showing the relationship between the rotational speeds of the bit rotary motor and the bit movement motor in a feedback (FB) controlled system. Figure 24B This is a graph showing the relationship between the screw's moving speed generated by the rotation of the bit rotary motor based on feedback (FB) control and the screw bit's moving speed generated by the bit movement motor. Next, referring to the graphs, other variations of the fastening operation of the fastening tool in this embodiment will be described. In this variation, the screw's moving speed generated by the rotation of the bit rotary motor 40 and the screw bit's moving speed generated by the bit movement motor 50 are synchronized by feedback control.

[0250] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0251] Control unit 100 Figure 23 In step SE1, the rotation speed of the bit movement motor 50, which determines the forward advance of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SE2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SE3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SE4, and drives the bit movement motor 50 of the second drive unit 5 in step SE5.

[0252] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0253] As a result, the screwdriver bit 2 held in the holding member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0254] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0255] Therefore, the screwdriver bit 2 held in the holding member 30 causes the screw 200 to rotate in the positive direction (clockwise) and be screwed into the object to be fastened. The control unit 100, in conjunction with the action of rotating the screwdriver bit 2 through the first drive unit 4 to screw the screw into the object to be fastened, moves the screwdriver bit 2 forward through the second drive unit 5, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0256] In step SE6, the control unit 100 determines whether the rotational speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. If the control unit 100 determines that the rotational speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, then in step SE7, it detects the load applied to the bit movement motor 50. When a predetermined load is detected, in step SE8, it obtains the rotational speed of the bit rotation motor 40 and the rotational speed of the bit movement motor 50.

[0257] In step SE9, the control unit 100 determines the speed at which the screw 200 moves forward to be fastened to the object by the rotation of the bit rotation motor 40, and the speed at which the retaining member 30 and the moving member 32, which move forward by the rotation of the bit movement motor 50, and the screwdriver bit 2 mounted on the retaining member 30 move forward as follows: Figure 24B As shown, the target speed of the bit moving motor 50 is calculated based on the gear ratio of the reducer of the bit rotating motor 40 and the rotation speed of the bit rotating motor 40, or the target speed of the bit rotating motor 40 is calculated based on the gear ratio of the reducer of the bit moving motor 50 and the rotation speed of the bit moving motor 50.

[0258] In step SE10, the control unit 100 controls the bit moving motor 50 in this example through feedback control based on the target speed of the bit rotary motor 40, the target speed of the bit moving motor 50, the gear ratio of the reducer, etc. For example, the speed is adjusted by increasing or decreasing the PWM output to the bit moving motor 50.

[0259] In step SE6, the control unit 100 determines that the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110 and the front end of the screwdriver bit 2 has reached the set end position P2. In step SE11, the control unit 100 stops the drive of the bit rotation motor 40. In step SE12, the control unit stops the rotation of the bit movement motor 50 in the positive direction. In step SE13, the control unit 100 reverses the bit movement motor 50.

[0260] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0261] In step SE14, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding member 30 and the moving member 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SE15, the reverse rotation of the bit moving motor 50 is stopped.

[0262] Furthermore, the aforementioned feedback control is required after the load on the bit rotation motor 40 and bit movement motor 50 changes due to contact between the fastening object and the screw 200. Therefore, the control without feedback control is designated as the first control mode, and the control with feedback control is designated as the second control mode. The first control mode is executed before a predetermined load is detected by either or both of the bit rotation motor 40 and bit movement motor 50. Moreover, when a predetermined load is detected by either or both of the bit rotation motor 40 and bit movement motor 50, the first control mode is switched to the second control mode, and the second control mode is executed. This suppresses delays in operation time.

[0263] Furthermore, as a means to improve the responsiveness of feedback control and achieve more stable work quality, the acceleration / deceleration limit value of the bit movement motor 50 can be changed during feedback control execution after load detection and during feedback control non-execution before load detection. Normally, when providing PWM output to the motor, control is performed to stabilize the motor output by limiting the acceleration per unit time, particularly to prevent excessive acceleration current during startup. However, if the aforementioned feedback control is performed while acceleration is limited during startup of the bit movement motor 50, the PWM output generated in the feedback control is restricted and applied to the bit movement motor 50, thus deteriorating the responsiveness to feedback control. Therefore, during feedback control execution, it is preferable to set the acceleration limit value to be larger than that during motor startup when feedback control is not executed.

[0264] Figure 25 This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Figure 26A , Figure 26B This is a graph showing the relationship between the load and the control of the bit movement motor. Next, referring to the graphs, other variations of the fastening operation of the fastening tool in this embodiment will be described. In this variation, the load applied to the bit movement motor 50 is detected, and the bit movement motor 50 is controlled.

[0265] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0266] Control unit 100 Figure 25 In step SF1, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SF2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SF3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SF4, and drives the bit movement motor 50 of the second drive unit 5 in step SF5.

[0267] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0268] As a result, the screwdriver bit 2 held in the holding member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0269] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0270] Therefore, the screwdriver bit 2 held in the holding member 30 causes the screw 200 to rotate in the positive direction (clockwise) and be screwed into the object to be fastened. The control unit 100, in conjunction with the action of rotating the screwdriver bit 2 through the first drive unit 4 to screw the screw into the object to be fastened, moves the screwdriver bit 2 forward through the second drive unit 5, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0271] In step SF6, the control unit 100 determines whether the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. If the control unit 100 determines that the rotation speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, in step SF7, the control unit 100 detects the load applied to the bit movement motor 50. When a predetermined load is detected, in step SF8, the control unit 100 controls the bit movement motor 50.

[0272] The bit moving motor 50 drives the holding member 30 and the moving member 32 to move forward. As a result, when the screw 200 is pressed against the object being fastened, in order to suppress the generation of excessive impact, the bit rotating motor 40 operates at the maximum output within the assumed range without reducing the tightening speed. Furthermore, the output of the bit moving motor 50 is limited by reducing the voltage applied to the bit moving motor 50 and reducing the current flowing through the bit moving motor 50.

[0273] When the ratio of the advance of the screwdriver bit 2 per revolution of the bit movement motor 50 to the advance of the screw per revolution of the bit rotation motor 40 decreases, the advance of the screwdriver bit 2 generated by the bit movement motor 50 cannot keep up with the advance of the screw generated by the bit rotation motor 40, thus causing it to come loose. On the other hand, if the ratio of the advance of the screwdriver bit 2 per revolution of the bit movement motor 50 to the advance of the screw per revolution of the bit rotation motor 40 increases, the advance of the screwdriver bit 2 generated by the bit movement motor 50 greatly exceeds the advance of the screw generated by the bit rotation motor 40, thus requiring excessive force for the operator to press the fastening tool 1 towards the object being fastened.

[0274] Therefore, as a target value for output limitation, the preferred ratio of the advance of the screwdriver bit 2 per revolution of the bit movement motor 50 to the advance of the screw per revolution of the bit rotation motor 40 is approximately 0.8 to 5 times. This suppresses the occurrence of dislodgement and eliminates the need for excessive force from the operator to press the fastening tool 1 towards the object being fastened, thus preventing excessive impact when the screw 200 is pressed against the object.

[0275] In addition, when the load on the bit movement motor 50 generated after the fastening object comes into contact with the screw 200 is detected, by limiting the output of the bit movement motor 50, the retaining member 30 and the moving member 32 can be decelerated when the screw 200 is pressed against the fastening object, and the effect of further suppressing the impact can be obtained.

[0276] In the control of limiting the output of the bit movement motor 50, such as Figure 26A As shown, the output can also be limited so that after a predetermined load is detected, the bit moving motor 50 maintains a constant speed until the bit rotating motor 40 rotates the screwdriver bit 2 to the end position of the operation. Additionally, as... Figure 26BAs shown, before a predetermined load is detected, the bit movement motor 50 rotates forward at a first speed. After the predetermined load is detected, in order to reduce the impact when the screw 200 is pressed against the fastening object, the bit movement motor 50 rotates forward at a second speed with a reduced speed. Furthermore, the output can be limited so that after a predetermined buffer time during which the impact of the screw 200 being pressed against the fastening object weakens, the speed becomes constant at a third speed, slower than the first speed but faster than the second speed, until the bit rotation motor 40 rotates the screwdriver bit 2 to the end position of the operation.

[0277] Furthermore, due to fluctuations in the power supply voltage, a difference arises in the moving speed (forward speed) of the holding component 30 and the moving component 32. The higher the power supply voltage, the faster the moving speed, which can easily cause excessive impact when the screw 200 is pressed against the object being fastened. Therefore, the control unit 100 detects the power supply voltage, and the higher the power supply voltage, the lower the output of the bit moving motor 50 is compared to the case of a low power supply voltage.

[0278] Therefore, it is possible to suppress the difference in rotational speed of the bit movement motor 50 caused by fluctuations in the power supply voltage. Thus, when the screw 200 is pressed against the object being fastened, it is possible to suppress excessive impact and to suppress deviations in the speed at which the screw 200 is pressed against the object being fastened.

[0279] In step SF6, when the control unit 100 determines that the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110 and the front end of the screwdriver bit 2 has reached the set end position P2, the control unit 100 stops the drive of the bit rotation motor 40 in step SF9, and after stopping the rotation of the bit movement motor 50 in the positive direction in step SF10, the control unit 100 reverses the bit movement motor 50 in step SF11.

[0280] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0281] In step SF12, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SF13, the reverse rotation of the bit moving motor 50 is stopped.

[0282] Figure 27This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Next, referring to the figures, other variations of the fastening operation of the fastening tool according to this embodiment will be described. In this variation, the load applied to the bit movement motor 50, etc., is detected to suppress drive in the absence of screws.

[0283] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0284] Control unit 100 Figure 27 In step SG1, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SG2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SG3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SG4, and drives the bit movement motor 50 of the second drive unit 5 in step SG5.

[0285] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0286] As a result, the screwdriver bit 2 held in the holding member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0287] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0288] Therefore, the screwdriver bit 2 held in the holding member 30 causes the screw 200 to rotate in the positive direction (clockwise) and be screwed into the object to be fastened. The control unit 100, in conjunction with the action of rotating the screwdriver bit 2 through the first drive unit 4 to screw the screw into the object to be fastened, moves the screwdriver bit 2 forward through the second drive unit 5, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0289] In step SG6, the control unit 100 determines whether the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. If the control unit 100 determines that the rotation speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, in step SG7, the control unit 100 detects the load applied to either or both of the bit rotation motor 40 and the bit movement motor 50. If a predetermined load is detected by pressing the screw 200 against the object being fastened, the bit movement motor 50 continues to rotate in the positive direction until the rotation speed of the bit movement motor 50 reaches the set value selected by the setting unit 110.

[0290] In step SG6, the control unit 100 determines that the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110 and the front end of the screwdriver bit 2 has reached the set end position P2. In step SG8, ​​the control unit 100 stops the drive of the bit rotation motor 40. In step SG9, the control unit 100 stops the rotation of the bit movement motor 50 in the positive direction and then reverses the bit movement motor 50 in step SG10.

[0291] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0292] In step SG11, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SG12, the reverse rotation of the bit moving motor 50 is stopped.

[0293] When there is no screw 200 at the injection port 81a, when the bit rotation motor 40 and bit movement motor 50 rotate in the positive direction, the load applied to the bit rotation motor 40 and bit movement motor 50 will not increase because the screw 200 is not pressed against the object being fastened. Therefore, even if the screwdriver bit 2 mounted on the holding member 30 advances by a predetermined amount of movement based on the length of the minimum screw 200 loaded, if no predetermined load is detected, it can be determined that there is no screw 200.

[0294] Therefore, in step SG13, the control unit 100 determines whether the bit movement motor 50 has rotated by a predetermined amount of movement based on the length of the smallest screw 200 loaded, and whether the screwdriver bit 2 mounted on the holding member 30 has advanced by a predetermined amount of idle motion detection. Furthermore, if the control unit 100 determines that either the bit rotation motor 40 or the bit movement motor 50, or both, have not detected a predetermined load, and determines that the bit movement motor 50 has rotated by the predetermined amount of idle motion detection, it determines that there is no screw 200, and issues an error notification in step SG14. Additionally, in the processing of steps SG8 to SG12 described above, the driving of the bit rotation motor 40 and the bit movement motor 50 is stopped.

[0295] The control unit 100 can also detect the load applied to either or both of the bit rotation motor 40 and bit movement motor 50 based on changes in the current flowing through the motor, in addition to changes in the current generated when the motor starts. Alternatively, it can detect changes in the voltage flowing through the motor, in addition to changes in the voltage generated when the motor starts. Furthermore, it can be a structure where a single motor performs the rotation of the bit holder 3 and the axial movement of the bit holder 3, and the control unit 100 can also detect the load applied to the single motor to suppress drive in the absence of screws.

[0296] Next, other variations of the fastening operation of the fastening tool according to this embodiment will be described. In this variation, in the feedback control of the screwdriver bit movement speed generated by the bit movement motor 50 following (synchronizing) the screw movement speed generated by the rotation of the bit rotation motor 40, the movement speed of the bit holding part 3 is calculated using the lead length of the screw 200 obtained during the previous screw tightening operation. Furthermore, in this variation, the lead length of the screw 200 refers to the distance the screw 200 advances per revolution.

[0297] Figure 28 This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Furthermore, a graph showing the relationship between the rotational speeds of the bit rotary motor and the bit movement motor based on feedback (FB) control is also included. Figure 24A Commonly, a graph showing the relationship between the screw travel speed generated by the rotation of the bit rotary motor based on feedback (FB) control and the screw bit travel speed generated by the bit movement motor, and... Figure 24B This is common to all charts; therefore, for explanations of each chart, please refer to [link / reference]. Figure 24A and Figure 24B Please provide an explanation.

[0298] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0299] Control unit 100 Figure 28 In step SH1, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SH2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SH3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SH4, and drives the bit movement motor 50 of the second drive unit 5 in step SH5.

[0300] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0301] As a result, the screwdriver bit 2 held in the holding member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0302] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0303] Therefore, the screwdriver bit 2 held in the holding member 30 causes the screw 200 to rotate in the positive direction (clockwise) and be screwed into the object to be fastened. The control unit 100, in conjunction with the action of rotating the screwdriver bit 2 through the first drive unit 4 to screw the screw into the object to be fastened, moves the screwdriver bit 2 forward through the second drive unit 5, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0304] In step SH6, the control unit 100 determines whether the rotational speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. If the control unit 100 determines that the rotational speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, in step SH7, the control unit 100 detects the load applied to at least one of the bit rotation motor 40 and the bit movement motor 50. When a predetermined load is detected, in step SH8, the control unit 100 obtains the rotational speed of the bit rotation motor 40 and the rotational speed of the bit movement motor 50.

[0305] In step SH9, the control unit 100 uses information about the lead length of the screw 200 obtained during the previous screw tightening operation to calculate the target rotation speed of the bit movement motor 50. Specifically, this involves calculating the forward speed of the screw 200 as it moves forward to tighten the screw 200 to the object being tightened via the rotation of the bit rotation motor 40, and the forward speeds of the retaining member 30, the moving member 32, and the screwdriver bit 2 mounted on the retaining member 30, which move forward via the rotation of the bit movement motor 50. Figure 24B As shown, the target rotational speed of the bit moving motor 50 is determined based on the lead length of the screw 200, the rotational speed of the bit rotating motor 40, the gear ratio of the reducer, etc. For example, the control unit 100 calculates the target rotational speed of the bit moving motor 50 based on the following formula (1).

[0306] The target speed of the bit moving motor 50 = (gear ratio of the reducer of the bit moving motor 50 / gear ratio of the reducer of the bit rotating motor 40 × circumference of pulley 52 / lead length of screw 200) × speed of bit rotating motor 40 ... (1)

[0307] In step SH10, the control unit 100 controls the bit movement motor 50 to achieve the calculated target speed through feedback control based on the gear ratio of the speed reducer of the bit rotation motor 40, in this example. For example, the speed is adjusted by increasing or decreasing the PWM output to the bit movement motor 50.

[0308] In step SH11, the control unit 100 measures and detects the rotation speed of the bit rotating motor 40 after a load has been applied to either the bit rotating motor 40 or the bit moving motor 50. Additionally, in step SH12, the control unit 100 measures and detects the rotation speed of the bit moving motor 50 after a load has been applied to either the bit rotating motor 40 or the bit moving motor 50. The rotation speeds of the bit rotating motor 40 and the bit moving motor 50 measured in steps SH11 and SH12 are stored in a memory (not shown) and used in step SH18 to calculate the lead length of the screw 200 for the next screw tightening operation. After the measurement in step SH12 is completed, the process returns to step SH6.

[0309] In step SH6, the control unit 100 determines that the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110 and the front end of the screwdriver bit 2 has reached the set end position P2. In step SH13, the control unit 100 stops the drive of the bit rotation motor 40. In step SH14, the control unit 100 stops the rotation of the bit movement motor 50 in the positive direction and then reverses the bit movement motor 50 in step SH15.

[0310] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0311] In step SH16, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SH17, the reverse rotation of the bit moving motor 50 is stopped.

[0312] When a series of screw tightening operations are completed, the control unit 100 calculates the lead length of the screw 200 in step SH18 according to the following sequence. Furthermore, the calculation of the lead length of the screw 200 can be performed not only after the screw tightening operations are completed, but also before or after the processing in step SH13 or SH14, in parallel with the reverse control of the bit movement motor 50, etc.

[0313] First, the number of rotations of screw 200 is calculated based on the following formula (2).

[0314] The number of revolutions of screw 200 = the number of revolutions of bit rotation motor 40 from the start of screw tightening (after load test) until screw 200 is fully tightened (step SH11) / the gear ratio of the reducer of bit rotation motor 40 ... (2)

[0315] Furthermore, in the above formula (2), the number of revolutions of the bit rotating motor 40 is obtained in the entire interval from the load detection to the screw 200 being fully tightened, but it is not limited to this, and the number of revolutions of the bit rotating motor 40 can also be obtained in a part of the entire interval.

[0316] Next, the length of screw 200 is calculated based on the following formula (3).

[0317] The length of screw 200 (the amount of movement of screwdriver bit 2 from the start of screw tightening to the time when screw 200 is fully tightened) = the number of revolutions of bit moving motor 50 from the start of screw tightening to the time when screw is fully tightened (step SH12) / the gear ratio of the reducer of bit moving motor 50 × the circumference of pulley 52 ... (3)

[0318] Furthermore, in the above formula (3), the number of revolutions of the bit moving motor 50 is obtained in the entire interval from the load detection to the screw 200 being fully tightened, but it is not limited to this, and the number of revolutions of the bit moving motor 50 can also be obtained in a part of the entire interval.

[0319] Next, the lead length of screw 200 is calculated based on the following equation (4).

[0320] Lead length of screw 200 = Length of screw 200 (Equation (3)) / Number of rotations of screw 200 (Equation (2)) ... (4)

[0321] The control unit 100 stores the calculated lead length of the screw 200 in a memory (not shown) and resets it as the lead length used when calculating the rotational speed of the bit movement motor 50 after load detection during the next screw tightening operation. Thus, in this modified example, the lead length of the screw 200 used is calculated based on one cycle of screw tightening operation, and the calculated lead length is used to calculate the penetration speed (movement speed) of the screwdriver bit 2 per revolution to the object being tightened and the rotational speed of the bit movement motor 50 during the next screw tightening operation.

[0322] According to this modified example, by estimating the lead length of the screw 200 used in the screw tightening operation, the penetration depth and penetration speed of the screw 200 into the object being tightened, driven by the bit rotation motor 40, can be accurately calculated. Therefore, in screw tightening after load testing, the moving speed of the screwdriver bit 2 can accurately follow the penetration speed of the screw 200. By reducing the force required to press the tightening tool 1 during screw tightening, the workload can be reduced, and by suppressing the lifting of the tightening tool 1, the driving quality can be improved.

[0323] Next, other variations of the fastening operation of the fastening tool according to this embodiment will be described. In this variation, in the feedback control that makes the moving speed of the screwdriver bit generated by the bit moving motor 50 follow the moving speed of the screw generated by the rotation of the bit rotating motor 40, the target rotation speed of the bit moving motor 50 is calculated using the lead length of the screw set by the lead length setting unit 120.

[0324] Figure 29 This is a block diagram illustrating other variations of the operation of the fastening tool in this embodiment. For example... Figure 29 As shown, the control unit 100 of the fastening tool 1A is connected to a bit rotation motor 40, a bit movement motor 50, a contact switch unit 84, a trigger switch unit 90, a setting unit 110, and a lead length setting unit 120.

[0325] The lead length setting unit 120 accepts the lead length setting corresponding to the type of screw 200 and outputs the accepted lead length information to the control unit 100. For example, the lead length setting unit 120 may also be provided in the tool body 10. In this case, the lead length setting unit 120 may also be configured as an operation unit such as a button or a rotary dial, allowing the user to manually input the lead length of the screw 200 by operating these buttons, or the user to select a specific lead length from a plurality of preset lead lengths. Alternatively, for example, an information processing terminal such as a personal computer, tablet computer, or smartphone may be equipped with the function of the lead length setting unit 120, and the lead length of the screw 200 input by the information processing terminal may be transmitted to the control unit 100 in the fastening tool 1 via wired or wireless communication.

[0326] The control unit 100 changes the lead length used when calculating the rotational speed of the bit movement motor 50 (described later) to the lead length of the screw 200 set by the lead length setting unit 120. This allows switching from information about the lead length of the screw 200 from the previous screw tightening operation to information about the lead length of the screw 200 used in the current screw tightening operation.

[0327] Figure 30 This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Furthermore, a graph showing the relationship between the rotational speeds of the bit rotary motor and the bit movement motor based on feedback (FB) control is also included. Figure 24A Commonly, a graph showing the relationship between the screw travel speed generated by the rotation of the bit rotary motor based on feedback (FB) control and the screw bit travel speed generated by the bit movement motor, and... Figure 24B This is common to all charts; therefore, for explanations of each chart, please refer to [link / reference]. Figure 24A and Figure 24B Please provide an explanation.

[0328] When the fastening tool 1A is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0329] Control unit 100 Figure 30 In step SI1, the rotation speed of the screwdriver bit movement motor 50, which specifies the forward movement of the screwdriver bit 2, is set according to the setting value selected by the setting unit 110.

[0330] In step SI2, the lead length setting unit 120 accepts a lead length setting corresponding to the type of screw 200 based on the operator's operation. After accepting the lead length setting, it proceeds to step SI3. If no lead length setting for the screw 200 is accepted, the lead length setting used in the last screw tightening operation is maintained.

[0331] In step SI3, the control unit 100 sets the lead length of the screw 200 received by the lead length setting unit 120 to the lead length used when calculating the rotational speed of the bit movement motor 50 (described later). Additionally, the information regarding the lead length of the screw 200 received by the lead length setting unit 120 is stored in a memory (not shown). After setting the new lead length, the process proceeds to step SI4.

[0332] When the contact member 81 is pressed against the object to be fastened, the contact switch part 84 is pushed by the contact arm 82. In step SI4, the contact switch part 84 is turned on, and the trigger 9 is operated. In step SI5, when the trigger switch part 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SI6, and drives the bit movement motor 50 of the second drive unit 5 in step SI7.

[0333] When the bit movement motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a, move forward. As a result, the screwdriver bit 2 held in the holding part 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0334] Furthermore, when the screwdriver bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 and the rotation guide member 31 rotate together. As a result, the screwdriver bit 2 held in the holding member 30 causes the screw 200 to rotate in the positive direction (clockwise) and be screwed into the object being fastened. The control unit 100, in conjunction with the operation of rotating the screwdriver bit 2 via the first drive unit 4 to screw the screw into the object, moves the screwdriver bit 2 forward via the second drive unit 5, thereby causing the screwdriver bit 2 to follow the screw being screwed into the object.

[0335] In step SI8, the control unit 100 determines whether the rotation speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. If the control unit 100 determines that the rotation speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, it proceeds to step SI9.

[0336] In step SI9, the control unit 100 detects whether at least one of the bit rotation motor 40 and bit movement motor 50 is under load. When a predetermined load is detected, in step SI10, the rotational speed of the bit rotation motor 40 and the rotational speed of the bit movement motor 50 are obtained respectively.

[0337] In step SI11, when the screw 200 is tightened to the object by the rotation of the bit rotation motor 40, the control unit 100 ensures that the forward movement speed of the screw 200 is approximately the same as the forward movement speed of the screwdriver bit 2, which is moved forward by the rotation of the bit movement motor 50 (see reference). Figure 24B The target rotational speeds of the screw 200 and the bit moving motor 50 are determined based on the lead length of the screw 200 set by the lead length setting unit 120, the rotational speed of the bit rotating motor 40 and the rotational speed of the bit moving motor 50, the gear ratio of the reducer, etc. For example, the control unit 100 calculates the target rotational speed of the bit moving motor 50 based on the following formula (5).

[0338] The target speed of the bit moving motor 50 = (gear ratio of the reducer of the bit moving motor 50 / gear ratio of the reducer of the bit rotating motor 40 × circumference of pulley 52 / lead length of screw 200) × speed of bit rotating motor 40 ... (5)

[0339] In step SI12, the control unit 100 controls the bit moving motor 50 to achieve the calculated target speed through feedback control based on the rotational speed of the bit rotary motor 40, the rotational speed of the bit moving motor 50, the gear ratio of the reducer, etc. In this example, the bit moving motor 50 is controlled to achieve the target rotational speed. For example, the speed is adjusted by increasing or decreasing the PWM output to the bit moving motor 50.

[0340] In step SI8, the control unit 100 determines that the rotation speed of the bit movement motor 50 has become the set value selected by the setting unit 110. When the front end of the screwdriver bit 2 reaches the set end position P2, the control unit 100 stops the drive of the bit rotation motor 40 in step SI13. After stopping the rotation of the bit movement motor 50 in the positive direction in step SI14, the control unit 100 reverses the bit movement motor 50 in step SI15.

[0341] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0342] In step SI16, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding member 30 and the moving member 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SI17, the reverse rotation of the bit moving motor 50 is stopped.

[0343] The unit for setting the lead length of the switching screw 200 can be a unit other than the lead length setting unit 120. Specifically, a communication unit can be provided on the fastening tool 1A, etc., and a non-powered communication unit can be provided on the side of the connecting strip (reel) on which multiple screws 200 are loaded in the screw storage unit 6, so that short-range wireless communication can be performed between the communication unit and the non-powered communication unit. The non-wireless communication unit houses, for example, an IC chip that stores, in a correspondence between the type of screw 200 and the lead length of that screw 200. When the connecting strip is stored in the screw storage unit 6, the communication unit obtains the lead length of the screw 200 for which the screw fastening operation is performed by wirelessly communicating with the non-wireless communication unit, and the control unit 100 switches the lead length setting to the obtained new lead length. Examples of short-range wireless communication methods include contactless methods using electromagnetic fields or radio waves, Bluetooth (registered trademark), etc.

[0344] Alternatively, the unit for setting the lead length of the switching screw 200 can also be a recognition unit that mechanically identifies the size of the connecting strip loaded in the screw storage section 6. In this case, the lead length varies depending on the type of screw 200, and consequently, the width, slot position, and number of the connecting strip also differ. Therefore, based on these differences in the connecting strip, the type of connecting strip is mechanically identified to obtain the lead length of the screw 200.

[0345] According to this modified example, even when different types of screws 200 are used, the lead length setting unit 120 can switch the lead length setting. Therefore, since it is possible to switch to the lead length of the screw 200 actually used in the screw tightening operation, compared to, for example, using the previous lead length to calculate the rotational speed of the bit movement motor 50, the penetration depth and penetration speed of the screw 200 into the object being tightened by the drive of the bit rotation motor 40 can be calculated more accurately. As a result, in screw tightening after load testing, the moving speed of the screwdriver bit 2 can accurately follow the penetration speed of the screw 200, the workload can be reduced by decreasing the force required to press the tightening tool 1A during screw tightening, and the driving quality can be improved by suppressing the lifting of the tightening tool 1A.

[0346] Next, other variations of the fastening operation of the fastening tool according to this embodiment will be described. In this variation, in the feedback control of the screwdriver bit movement speed generated by the bit movement motor 50 following (synchronizing) the screw movement speed generated by the rotation of the bit rotation motor 40, the control is performed in such a way that the current value of the bit movement motor 50 converges within a specified range during the screw fastening operation.

[0347] Figure 31 This is a flowchart illustrating other variations of the operation of the fastening tool according to this embodiment. Figure 32 It is a graph showing the relationship between load and the control of the bit movement motor. Figure 33 It is a diagram showing the engagement state between the screwdriver bit and the groove of the screw when the screw is tightened.

[0348] Fastening tool 1 is in standby mode, such as Figure 1A As shown, the front end of the screwdriver bit 2 is located in the standby position P1 behind the injection passage 80, and can supply screws 200 to the injection passage 80.

[0349] Control unit 100 Figure 31 In step SJ1, the rotation speed of the bit movement motor 50, which determines the advance amount of the screwdriver bit 2, is set based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object being fastened, the contact switch 84 is pushed by the contact arm 82. In step SJ2, the contact switch 84 is turned on, and the trigger 9 is activated. In step SJ3, when the trigger switch 90 is turned on, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SJ4, and drives the bit movement motor 50 of the second drive unit 5 in step SJ5.

[0350] When the bit moving motor 50 is driven to rotate in the positive direction, the pulley 52 rotates in the positive direction, thereby winding the wire 54 onto the pulley 52. ​​The second moving part 32c, the moving part 32 connected to the wire 54, and the holding part 30 connected to the moving part 32 via the first moving part 32a move forward.

[0351] As a result, the screwdriver bit 2 held in the holding member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the ejection port 81a of the head 8, and causes the screw 200 to move forward and press against the object to be fastened.

[0352] In addition, when the bit rotation motor 40 is driven to rotate in the positive direction, the holding member 30 rotates together with the rotation guide member 31.

[0353] Therefore, the screwdriver bit 2 held in the holding member 30 causes the screw 200 to rotate in the positive direction (clockwise) and be screwed into the object to be fastened. The control unit 100, in conjunction with the action of rotating the screwdriver bit 2 through the first drive unit 4 to screw the screw into the object to be fastened, moves the screwdriver bit 2 forward through the second drive unit 5, so that the screwdriver bit 2 follows the screw that is screwed into the object to be fastened.

[0354] In step SJ6, the control unit 100 determines whether the rotational speed of the bit movement motor 50 has reached the set value selected by the setting unit 110, and whether the tip of the screwdriver bit 2 has reached the set end position P2. If the control unit 100 determines that the rotational speed of the bit movement motor 50 has not reached the set value selected by the setting unit 110, in step SJ7, the control unit 100 detects the load applied to the bit movement motor 50. When a predetermined load is detected, in step SJ8, the control unit 100 obtains the rotational speed of the bit movement motor 50.

[0355] In step SJ9, when the control unit 100 determines that a screw tightening operation is in progress by detecting a predetermined load, it sets the current value of the bit movement motor 50 based on the obtained rotation speed of the bit movement motor 50, so that it converges within a predetermined range. Therefore, during screw tightening operations, even if the advance of the screw 200 is fast or slow depending on the state of the object being tightened, the output torque remains constant. Thus, based on the screwdriver bit 2 following the advancing screw 200, the operator can perform screw tightening operations by pressing the tightening tool 1 against the object being tightened without applying excessive force.

[0356] In addition, such as Figure 32 As shown, after detecting the load of screw tightening, the target value of the current of the bit moving motor 50 is set in a manner that gradually increases in accordance with the increase of the load during screw tightening and the decrease of the rotation speed of the bit rotating motor 40 during screw tightening. The reason is as follows. During screw tightening, it is necessary to continuously maintain the engagement between the screwdriver bit 2 and the screw groove. However, if the load during screw tightening increases, then... Figure 33 As shown, along the wall 200a of the engagement portion of the screw groove, the forces acting in directions B1 and B2 that cause the screwdriver bit 2 to disengage from the screw 200 increase. Therefore, it is necessary to increase the force pressing the screwdriver bit 2 against the screw 200 to prevent the screwdriver bit 2 from disengaging from the screw 200. Preferably, the current value of the screwdriver bit moving motor 50 is increased each time a screw tightening operation is performed.

[0357] Therefore, as Figure 32As shown, when the current value immediately after detecting the load of the screw tightening operation is set as the first predetermined value T1, and the current value at the end of the screw tightening operation is set as the second predetermined value T2, for example, the control unit 100 sets the first predetermined value T1 to converge within a range of 10A to 30A, and sets the second predetermined value T2 to converge within a range of more than 30A to 60A. In this case, during the current control implementation, the control unit 100 sets the current value of the bit movement motor 50 in a manner that gradually increases from the set first predetermined value T1 to the second predetermined value T2. In addition, if the rotation speed of the bit movement motor 50 obtained in step SJ8 is less than a preset threshold, it is preferable to set the current values ​​of the first predetermined value T1 and the second predetermined value T2 higher within the set range compared to the case where the rotation speed of the bit movement motor 50 is greater than the threshold. Furthermore, each of the first predetermined value T1 and the second predetermined value T2 can also be appropriately changed by the operator from the operation unit, etc. After setting each predetermined value, the process proceeds to step SJ10.

[0358] In step SJ10, the control unit 100 controls the bit movement motor 50 to converge the current value within a set range between a first predetermined value T1 and a second predetermined value T2. For example, the control unit 100 adjusts the rotational speed of the bit movement motor 50 by controlling the current value of the bit movement motor 50 within the range between the first predetermined value T1 and the second predetermined value T2 through PWM control based on the switching of the switching elements of the drive circuit.

[0359] In step SJ6, the control unit 100 determines that the rotation speed of the bit movement motor 50 has become the set value selected by the setting unit 110. When the front end of the screwdriver bit 2 reaches the set end position P2, the control unit 100 stops the drive of the bit rotation motor 40 in step SJ11. After stopping the rotation of the bit movement motor 50 in the positive direction in step SJ12, the control unit 100 reverses the bit movement motor 50 in step SJ13.

[0360] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, thereby pulling the wire 54 out of the pulley 52. ​​The second moving part 32c is pushed by the force-applying part 33, and the holding part 30 connected to the moving part 32 via the first moving part 32a moves in the rearward direction.

[0361] In step SJ14, if the bit moving motor 50 reverses to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and the holding component 30 and the moving component 32 move backward to the position where the front end of the screwdriver bit 2 returns to the standby position P1, then in step SJ15, the reverse rotation of the bit moving motor 50 is stopped.

[0362] According to this modified example, since the current value of the screwdriver bit movement motor 50 is controlled to converge within the range between a first predetermined value T1 and a second predetermined value T2, the force (load) of the screwdriver bit 2 pressing the screw 200 can be kept constant. Therefore, even if the advance of the screw 200 is fast or slow depending on the working state, the moving speed of the screwdriver bit 2 can follow the penetration speed of the screw 200 while maintaining the engagement between the screwdriver bit 2 and the groove of the screw 200. As a result, the workload is reduced by preventing excessive pressing of the tightening tool 1 during screw tightening, and the occurrence of lifting of the tightening tool 1 can be suppressed, thereby improving the driving quality.

[0363] Label Explanation

[0364] 1. 1A··· Fastening tool, 10··· Tool body, 10a··· Housing, 10b··· Front frame, 10c··· Rear frame, 10d··· Connecting part, 10e··· Screw, 10f··· Head body, 11··· Handle, 12··· Battery, 13··· Battery mounting part, 2··· Screwdriver bit, 3··· Bit holder, 30··· Holding part, 30a··· Opening, 30b··· 31. Connecting component; 31a. Rotary guide component; 32. Groove; 32a. First moving component; 32b. Bearing; 32c. Second moving component; 33. Force-applying component; 34a. Bearing; 4. First drive unit; 40. Bit rotary motor (motor, first motor); 40a. Shaft; 41. Reducer; 41a. Shaft; 42. 5. Bearing, 5. Second drive unit, 50. Bit moving motor (motor, second motor), 50a. Shaft, 51. Reducer, 51a. Shaft, 52. Pulley (transmission component), 53. Bearing, 54. Wire (transmission component), 6. Screw storage unit, 7. Screw feed unit, 70. Screw feed motor, 71. Pinion, 72. Rack, 73. Engaging part. 8··· Machine head, 80··· Injection passage, 81··· Contact component, 81a··· Injection outlet, 82··· Contact arm, 83··· Adjustment part, 84··· Contact switch part, 9··· Trigger, 90··· Trigger switch part, 100··· Control part, 110··· Setting part, 120··· Lead length setting part, T1··· First specified value (specified value), T2··· Second specified value (specified value).

Claims

1. A fastening tool, comprising: The screwdriver bit holder holds the screwdriver bit in a detachable manner and is rotatable in the circumferential direction and movable in the axial direction of the screwdriver bit; The first motor rotates the bit holding part; The second motor causes the bit holder to move axially. and The control unit uses the rotational speed of the second motor to control the axial position of the bit holder. The control unit controls the movement speed of the bit holder, which moves via the rotation of the second motor, based on the movement speed of the screw moved by the rotation of the first motor or the rotational speed of the first motor, so that the movement speed of the bit holder, which moves by the rotation of the second motor, follows the movement speed of the screw that moves by the rotation of the first motor to fasten the screw to the object being fastened. The control unit calculates the moving speed of the bit holder based on the lead length of the screw.

2. The fastening tool according to claim 1, wherein, The control unit controls the speed of the second motor based on the speed of the first motor, or controls the speed of the first motor based on the speed of the second motor.

3. The fastening tool according to claim 1 or 2, wherein, The control unit performs the following control: when a load is detected by the first motor or the second motor, the moving speed of the bit holder, which moves by the rotation of the second motor, follows the moving speed of the screw when it moves by the rotation of the first motor.

4. The fastening tool according to claim 1, wherein, The control unit uses the number of revolutions of the first motor or the amount of movement of the bit holder, measured after detecting a load applied to the first motor or the second motor, to calculate the lead length of the screw, and calculates the moving speed of the bit holder based on the calculated lead length.

5. The fastening tool according to claim 1, wherein, The fastening tool includes a lead length setting section capable of setting the lead length. The control unit calculates the moving speed of the bit holder based on the lead length of the screw set by the lead length setting unit.

6. The fastening tool according to claim 1, wherein, The control unit controls the moving speed of the bit holder, which moves due to the rotation of the second motor, based on the rotational speed of the first motor.

7. The fastening tool according to claim 6, wherein, The control unit controls the moving speed of the bit holder, which moves by the rotation of the second motor, based on the load applied to the first motor or the second motor.

8. The fastening tool according to claim 6 or 7, wherein, The control unit controls the moving speed of the bit holder, which moves by the rotation of the second motor, based on the variation of the power supply voltage.

9. The fastening tool according to claim 7, wherein, The control unit controls the second motor in a manner that brings the load within a specified range after detecting the load.

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