Agreement tools

Abstract

To provide a fastening tool that enables a movement speed of a driver bit to be controlled by an operation of moving the driver bit in a fastening direction of a screw.SOLUTION: A fastening tool 1 comprises: a bit holding part 3 that holds a driver bit 2 attachably and detachably and can rotate in a circumferential direction of the driver bit 2 and move in an axial direction of the driver bit; a bit rotating motor 40 that rotates the bit holding part 3; a bit moving motor 50 that moves the bit holding part 3 along the axial direction; and a control part 100 that controls a position along the axial direction of the bit holding part 3 at the rotation speed of the bit moving motor 50. The control part 100 performs control by which a movement speed of the bit holding part 3 that is moved by rotation of the bit moving motor 50 is made to follow a movement speed at which the screw moves, by fastening of the screw to an object to be fastened by rotation of the bit rotating motor 40.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to a fastening tool that engages a driver bit with a screw, presses the screw with the driver bit against a fastening object, and rotates the driver bit to screw it in.

Background Art

[0002] There is known a tool called a portable driving machine that uses the air pressure of compressed air supplied from an air compressor or the combustion pressure of gas to sequentially drive out the connecting fasteners loaded in a magazine from the tip of a driver guide.

[0003] Conventionally, there has been proposed a pneumatic screw driver that rotates a bit with an air motor and moves it in the direction of tightening the screw with air pressure in the direction of tightening the screw (see, for example, Patent Document 1).

[0004] Also, there has been proposed a screw driver that compresses a spring with the driving force of a motor that rotates a screw and drives in the screw by the biasing force of the spring (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In tools with a configuration that moves the bit in the direction of tightening a screw, the faster the bit moves forward than the screw's forward speed (determined by the screw's rotational speed), the greater the recoil, or so-called rebound, that causes the tool body to move away from the object being fastened. When the recoil is large, the tool body may lift away from the object being fastened, resisting the force applied by the operator to press the tool body against the object.

[0007] However, if the tool body lifts away from the object being fastened due to the recoil, the screw may not be fully tightened, resulting in an incomplete tightening of the screw. Therefore, to improve the quality of screw tightening, it is necessary to suppress the recoil, that is, to move (advance) the bit at an appropriate speed in accordance with the rotation speed of the screw.

[0008] However, conventional fastening tools lacked the concept of controlling the bit's forward speed in accordance with its rotational speed. Furthermore, both pneumatic and spring-driven screwdrivers made it difficult to control the driver bit's movement speed, as they were designed to move the driver bit in the direction of tightening the screw.

[0009] The present invention aims to solve these problems and provides a fastening tool that allows the movement speed of the driver bit to be controlled by moving the driver bit in the direction of tightening the screw. [Means for solving the problem]

[0010] To solve the above-mentioned problems, the present invention provides a bit holding part that detachably holds a driver bit, The aforementioned A first motor rotates the bit holder in the circumferential direction of the driver bit, The aforementioned A second motor moves the bit holder along the axial direction, The aforementioned The movement speed of the bit holder along the axial direction The aforementioned It comprises a control unit that controls the rotational speed of a second motor, The aforementioned The control unit is The aforementioned First motor and The aforementioned At least one of the motors of the second motor is Changes in current or voltage cause contact between the screw and the target component. When a predetermined load is detected, The aforementioned due to the rotation of the first motor It is fastened to the target component. screw of moves Synchronized with the above bit holder but moves vinegar so that The aforementioned based on the rotational speed of the first motor The aforementioned the rotational speed of the second motor is determined The system It is a fastening tool that executes control.

[0011] In the present invention, the moving speed of the driver bit follows the moving speed of the screw when the screw is fastened to the fastening object.

[0012] Further, the present invention includes a bit holder that detachably holds a driver bit, The aforementioned in the circumferential direction of the driver bit The aforementioned a first motor that rotates the bit holder, The aforementioned a second motor that moves the bit holder along the axial direction, The aforementioned the moving speed along the axial direction of the bit holder, The aforementioned and a control unit that controls with the rotational speed of the second motor, The aforementioned The control unit The aforementioned the first motor And at least one of the motors of the second motor is affected by a change in current or voltage. screw A predetermined result of contact between the target member and the target member. load When it detects , The movement of the screw fastened to the target member by the rotation of the first motor and the movement of the bit holding part that moves by the rotation of the second motor are synchronized. the rotation of the second motor The rotational speed of the first motor is determined based on the speed. control Execute It is a fastening tool that performs.

[0013] In the present invention, the moving speed of the driver bit is controlled in each of the operation of pressing the screw against the fastening object and the operation of fastening the screw to the fastening object.

Advantages of the Invention

[0014] In the present invention, the moving speed of the driver bit can be controlled in the operation of moving the driver bit in the direction of tightening the screw.

Brief Description of the Drawings

[0015] [Figure 1A]This is a side cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 1B] This is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 1C] This is a front cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 2A] This is an exploded perspective view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 2B] This is an external perspective view showing an example of a fastening tool according to this embodiment. [Figure 3A] This is a perspective view showing an example of the main components of the fastening tool according to this embodiment. [Figure 3B] This is a perspective view showing an example of the main components of the fastening tool according to this embodiment. [Figure 4A] This is a cross-sectional perspective view showing an example of the main components of the fastening tool according to this embodiment. [Figure 4B] This is a cross-sectional perspective view showing an example of the main components of the fastening tool according to this embodiment. [Figure 4C] This is a cross-sectional perspective view showing an example of the main components of the fastening tool according to this embodiment. [Figure 5] This is a top cross-sectional view showing an example of the main components of the fastening tool according to this embodiment. [Figure 6A] This is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 6B] This is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. [Figure 7A] This is a cross-sectional view showing an example of a detachable and retaining mechanism. [Figure 7B] This is a cross-sectional view showing an example of a detachable and retaining mechanism. [Figure 8A] This is a perspective view showing an example of a detachable and retaining mechanism. [Figure 8B] This is a perspective view showing an example of a detachable and retaining mechanism. [Figure 9] This is a perspective view showing an example of the screw feed section and nose section of this embodiment. [Figure 10A] This is a rearward perspective view showing an example of a fastening tool according to this embodiment. [Figure 10B] This is a rearward perspective view showing an example of a fastening tool according to this embodiment. [Figure 10C] This is a rearward perspective view showing an example of a fastening tool according to this embodiment. [Figure 11] This is a perspective view showing an example of the settings section. [Figure 12] This is a block diagram showing an example of a fastening tool in this embodiment. [Figure 13A] This is a side cross-sectional view showing an example of the operation of the fastening tool of this embodiment. [Figure 13B] This is a top cross-sectional view showing an example of the operation of the fastening tool of this embodiment. [Figure 14] This flowchart shows an example of the operation of the fastening tool in this embodiment. [Figure 15A] This is a cross-sectional view showing the tightening state of the screw. [Figure 15B] This is a cross-sectional view showing the tightening state of the screw. [Figure 15C] This is a cross-sectional view showing the tightening state of the screw. [Figure 16A] This is an explanatory diagram showing an example of the operation to set the standby positions of the holding member and the moving member in the first initialization operation. [Figure 16B] This is an explanatory diagram showing an example of the operation to set the standby positions of the holding member and the moving member in the first initialization operation. [Figure 16C] This is an explanatory diagram showing an example of the operation to set the standby positions of the holding member and the moving member in the first initialization operation. [Figure 16D] This is an explanatory diagram showing an example of the operation to set the standby positions of the holding member and the moving member in the first initialization operation. [Figure 17A] This is an explanatory diagram showing an example of the operation in which the holding member and the moving member are moved to the standby position during the second initialization operation. [Figure 17B] This is an explanatory diagram showing an example of the operation in which the holding member and the moving member are moved to the standby position during the second initialization operation. [Figure 17C]This is an explanatory diagram showing an example of the operation in which the holding member and the moving member are moved to the standby position during the second initialization operation. [Figure 18] This flowchart shows an example of the process of selecting between a first initialization operation and a second initialization operation. [Figure 19] This flowchart shows a modified example of the operation of the fastening tool according to this embodiment. [Figure 20] This graph shows the relationship between the output of the contact switch section and the control of the bit rotation motor and bit movement motor. [Figure 21] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 22A] This graph shows the relationship between the load and the control of the bit-rotating motor. [Figure 22B] This graph shows the relationship between the load and the control of the bit-rotating motor. [Figure 23] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 24A] This graph shows the relationship between the rotational speeds of the bit rotation motor and the bit movement motor under feedback control. [Figure 24B] This graph shows the relationship between the screw's movement speed due to the rotation of the bit rotation motor via feedback control and the driver bit's movement speed due to the bit movement motor. [Figure 25] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 26A] This graph shows the relationship between the load and the control of the bit-moving motor. [Figure 26B] This graph shows the relationship between the load and the control of the bit-moving motor. [Figure 27] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 28] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 29] This block diagram shows another variation of the operation of the fastening tool in this embodiment. [Figure 30] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 31] This flowchart shows another variation of the operation of the fastening tool of this embodiment. [Figure 32] This graph shows the relationship between the load during screw tightening and the control of the bit movement motor. [Figure 33] This diagram shows the engagement state between the driver bit and the screw recess when tightening a screw. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the fastening tool of the present invention will be described with reference to the drawings.

[0017] <Example of fastening tool configuration in this embodiment> Figure 1A is a side cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, Figure 1B is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, and Figure 1C is a front cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment. Furthermore, Figure 2A is an exploded perspective view showing an example of the internal structure of the fastening tool of this embodiment, and Figure 2B is an external perspective view showing an example of the fastening tool of this embodiment.

[0018] The fastening tool 1 of this embodiment includes a bit holding unit 3 that holds a driver bit 2 so that it can rotate and move in the axial direction, a first drive unit 4 that rotates the driver bit 2 held by the bit holding unit 3, and a second drive unit 5 that moves the driver bit 2 held by the bit holding unit 3 in the axial direction.

[0019] Furthermore, the fastening tool 1 includes a screw storage section 6 in which the screw 200 is stored, a screw feeding section 7 for feeding the screw stored in the screw storage section 6, and a nose section 8 that is pressed against the object to be fastened and from which the screw is ejected.

[0020] Furthermore, the fastening tool 1 comprises a tool body 10 and a handle 11. The fastening tool 1 also includes a battery mounting section 13 at the end of the handle 11, to which a battery 12 is detachably attached.

[0021] The fastening tool 1 has a tool body 10 that extends in one direction along the axial direction of the driver bit 2 indicated by arrows A1 and A2, and a handle 11 that extends in another direction intersecting the extension direction of the tool body 10. The direction in which the tool body 10 extends, i.e., the axial direction of the driver bit 2 indicated by arrows A1 and A2, is the front-back direction. The direction in which the handle 11 extends is the up-down direction. Furthermore, the direction perpendicular to the extension direction of the tool body 10 and the extension direction of the handle 11 is the left-right direction.

[0022] The first drive unit 4 is located at the rear of the tool body 10, on either side of the handle 11. The second drive unit 5 is located at the front of the tool body 10, on the other side of the handle 11.

[0023] The screw storage section 6 houses multiple screws 200 connected by connecting bands, forming spiral-wound connecting screws.

[0024] Figures 3A and 3B are perspective views showing an example of the main components of the fastening tool of this embodiment, Figures 4A to 4C are cross-sectional perspective views showing an example of the main components of the fastening tool of this embodiment, and Figure 5 is a top cross-sectional view showing an example of the main components of the fastening tool of this embodiment, showing details of the bit holding unit 3 and the first drive unit 4. Next, the bit holding unit 3 and the first drive unit 4 will be described with reference to each figure.

[0025] The bit holding section 3 is an example of a tip tool holding section and includes a holding member 30 that detachably holds a driver bit 2, which is an example of a tip tool; a rotating guide member 31 that supports the holding member 30 so as to be movable in the front-rear direction indicated by arrows A1 and A2 along the axial direction of the driver bit 2 and rotates together with the holding member 30; a moving member 32 that moves the holding member 30 in the front-rear direction along the rotating guide member 31; and a biasing member 33 that biases the moving member 32 in the rearward direction indicated by arrow A2.

[0026] The retaining member 30 is composed of a cylindrical member, for example, whose outer diameter is slightly smaller than the inner diameter of the rotating guide member 31 and which is placed inside the rotating guide member 31. The retaining member 30 has an opening 30a at the front end of the driver bit 2 along its axial direction, which matches the cross-sectional shape of the driver bit 2. The retaining member 30 is equipped with a detachable retaining mechanism 30c in the opening 30a for detachably holding the driver bit 2. The opening 30a of the retaining member 30 is exposed to the inside of the rotating guide member 31, and the driver bit 2 is detachably inserted into the opening 30a.

[0027] The rotating guide member 31 extends in the direction of extension of the tool body 10, that is, in the front-to-back direction indicated by arrows A1 and A2 along the axial direction of the driver bit 2. The rotating guide member 31 is cylindrical in shape with a retaining member 30 inside, and its front end is rotatably supported by a metal front frame 10b provided on the front side of the resin case 10a that constitutes the exterior of the tool body 10, via a bearing 34a, which is an example of a bearing. The rear end of the rotating guide member 31 is connected to the first drive unit 4.

[0028] The rotating guide member 31 has grooves 31a formed at two locations on its radially opposing sides, extending in the front-rear direction as indicated by arrows A1 and A2 along the axial direction of the driver bit 2. The rotating guide member 31 penetrates the holding member 30 radially, and connecting members 30b protruding from both sides of the holding member 30 enter the grooves 31a, thereby connecting the rotating guide member 31 to the holding member 30 via the connecting members 30b.

[0029] The retaining member 30 is provided with a hole that penetrates perpendicular to the rotational direction of the driver bit 2, and the connecting member 30b is inserted into this hole and fixed with a pin 30f. The connecting member 30b is composed of a cylindrical member with an oval cross-section.

[0030] The connecting member 30b has an oval shape, with its longitudinal direction aligned with the extension direction of the groove 31a, which is parallel to the axial direction of the driver bit 2 indicated by arrows A1 and A2, and an oval shape, with its short direction perpendicular to the extension direction of the groove 31a, indicated by arrows B1 and B2, that is, aligned with the rotation direction of the rotating guide member 31. Furthermore, the width of the connecting member 30b in the oval shape's short direction, that is, the width along the rotation direction of the rotating guide member 31, is slightly smaller than the width of the groove 31a along the same direction.

[0031] As a result, the connecting member 30b, which is placed in the groove 31a, is supported in the groove 31a so as to be movable along the axial direction of the rotating guide member 31. Furthermore, the movement of the connecting member 30b along the rotational direction relative to the rotating guide member 31 is restricted between one side and the other side of the groove 31a along the direction in which the groove 31a extends. Therefore, as the rotating guide member 31 rotates, the connecting member 30b is pushed against one side or the other side of the groove 31a depending on the rotational direction of the rotating guide member 31, and receives a circumferential force from the rotating guide member 31 that is in the rotational direction.

[0032] Therefore, when the rotating guide member 31 rotates, the connecting member 30b of the holding member 30 is pushed into the groove 31a of the rotating guide member 31, causing the holding member 30 to rotate together with the rotating guide member 31. In addition, the holding member 30 moves in the front-rear direction along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove 31a of the rotating guide member 31.

[0033] The movable member 32 is an example of a transmission member and includes a first movable member 32a that rotates together with the holding member 30 and moves the holding member 30 in the front-rear direction along the rotation guide member 31, a second movable member 32c that is supported by the first movable member 32a via a bearing 32b and pushes the first movable member 32a via the bearing 32b, and a cushioning member 32d attached to the rear side of the second movable member 32c.

[0034] The first movable member 32a is composed of, for example, a cylindrical member whose inner diameter is slightly larger than the outer diameter of the rotating guide member 31 and which is placed outside the rotating guide member 31. The first movable member 32a is connected to the holding member 30 via a connecting member 30b that protrudes from the groove 31a of the rotating guide member 31, thereby being supported so as to be movable along the axial direction of the rotating guide member 31.

[0035] The bearing 32b is an example of a bearing, inserted between the outer circumference of the first moving member 32a and the inner circumference of the second moving member 32c. The first moving member 32a constitutes a bearing inner ring retaining member that holds the inner ring of the bearing 32b, and the second moving member 32c constitutes a bearing outer ring retaining member that holds the outer ring of the bearing 32b. In the bearing 32b, the inner ring is supported on the outer circumference of the first moving member 32a so as to be unable to move in the rotational and axial directions, and the outer ring is supported on the inner circumference of the second moving member 32c so as to be unable to move in the rotational and axial directions.

[0036] As a result, the second movable member 32c is connected to the first movable member 32a via the bearing 32b, with its movement in the forward and backward direction along the axial direction restricted. The second movable member 32c also rotatably supports the first movable member 32a via the bearing 32b.

[0037] Therefore, the first moving member 32a is pushed by the second moving member 32c via the bearing 32b when the second moving member 32c moves in the forward and backward direction along the axial direction, and moves together with the second moving member 32c in the forward and backward direction along the axial direction. In addition, the first moving member 32a is rotatable relative to the second moving member 32c, which does not rotate relative to the rotating guide member 31.

[0038] In this example, the biasing member 33 is composed of a coil spring and is placed outside the rotating guide member 31, between the front frame 10b, which is provided on the front side of the case 10a of the tool body 10, and the second moving member 32c of the moving member 32, and contacts a spring seat 32f which is positioned to contact the end face of the outer ring of the bearing 32b. The biasing member 33 is compressed when the moving member 32 moves in the forward direction indicated by arrow A1, and applies a force to the moving member 32 that pushes it in the backward direction indicated by arrow A2.

[0039] The first drive unit 4 includes a bit rotation motor 40 and a reduction gear 41, which are driven by electricity supplied from the battery 12. The bit rotation motor 40 is an example of a motor or a first motor, and the shaft 40a of the bit rotation motor 40 is connected to the reduction gear 41, and the shaft 41a of the reduction gear 41 is connected to the rotation guide member 31. In the first drive unit 4, the reduction gear 41 is configured to use planetary gears, and the bit rotation motor 40 is arranged coaxially with the rotation guide member 31 and the holding member 30, and the driver bit 2 held by the holding member 30.

[0040] The first drive unit 4 has a bit rotation motor 40 and a reduction gear 41 mounted on a metal rear frame 10c provided on the rear side of the case 10a of the tool body 10, and the shaft 41a of the reduction gear 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 reduction gear 41, and the shaft 41a is supported on the rear frame 10c via a bearing 42, so that it is rotatably supported via the bearing 42, which is an example of a bearing.

[0041] The bit holder 3 and the first drive unit 4 are assembled as a single unit by connecting the front frame 10b and the rear frame 10c with a connecting member 10d that extends in the front-rear direction, and the front frame 10b is fixed to the case 10a of the tool body 10 with screws 10e.

[0042] Furthermore, the bit holder 3 is supported by a bearing 34a at the front end of the rotating guide member 31, which is fixed to the front of the case 10a of the tool body 10, and by a shaft 41a and bearing 42 of the reduction gear 41 at the rear end of the rotating guide member 31, which is fixed to the rear of the case 10a. Thus, the bit holder 3 is rotatably supported by the rotating guide member 31 on the tool body 10.

[0043] As a result, the first drive unit 4 rotates the rotating guide member 31 using the bit rotation motor 40. The holding member 30, which holds the driver bit 2, rotates together with the rotating guide member 31 as the connecting member 30b is pressed against the groove 31a of the rotating guide member 31.

[0044] The bit holder 3 has a guide member 32g on the second movable member 32c. The connecting member 10d has a pair of guide wall portions 10g spaced slightly larger than the diameter of the guide member 32g, and when the guide member 32g is placed between the pair of guide wall portions 10g, the pair of guide wall portions 10g face the circumferential surface of the guide member 32g.

[0045] As a result, the second movable member 32c is able to move in the forward and backward directions indicated by arrows A1 and A2 along the axial direction of the driver bit 2, with the guide member 32g being guided by the connecting member 10d, and its rotation following the rotation guide member 31 is restricted.

[0046] Figures 6A and 6B are top cross-sectional views showing an example of the internal structure of the fastening tool of this embodiment, and detail the second drive unit 5. Next, the second drive unit 5 will be described with reference to each figure.

[0047] The second drive unit 5 includes a bit moving motor 50 and a reduction gear 51, which are powered by electricity supplied from the battery 12. The bit moving motor 50 is an example of a motor or a second motor, and the shaft 50a of the bit moving motor 50 is connected to the reduction gear 51, and the shaft 51a of the reduction gear 51 is connected to a pulley 52, which is an example of a transmission member. In the second drive unit 5, the pulley 52 is supported on the tool body 10 via a bearing 53. In the second drive unit 5, the shaft 50a of the bit moving motor 50 is positioned along the extension direction of the handle 11.

[0048] The second drive unit 5 has one end of a linear wire 54, which is an example of a transmission member, connected to a pulley 52, and as the pulley 52 rotates, the wire 54 is wound around the pulley 52. ​​The other end of the wire 54 is connected to a wire connection part 32h provided on the second moving member 32c of the moving member 32.

[0049] As a result, the second drive unit 5 rotates the pulley 52 with the bit moving motor 50 and winds up the wire 54, thereby moving the second moving member 32c in the forward direction indicated by arrow A1. When the second moving member 32c moves forward, the first moving member 32a is pushed via the bearing 32b, and the first moving member 32a moves forward along the axial direction together with the second moving member 32c. When the first moving member 32a moves forward, the holding member 30, which is connected to the first moving member 32a via the connecting member 30b, moves forward, and the driver bit 2 held by the holding member 30 moves forward as indicated by arrow A1.

[0050] The second drive unit 5 is positioned offset to one side from the approximate center of the fastening tool 1 in the left-right direction, such that the tangential direction of the portion of the pulley 52 around which the wire 54 is wound is aligned with the extending direction of the rotating guide member 31. In other words, the center of the pulley 52, in this example, the shaft 50a of the bit moving motor 50, is offset to one side from the rotating guide member 31, and the portion 52a of the pulley 52 around which the wire 54 is wound overlaps with the rotating guide member 31 when viewed from the axial direction of the pulley 52.

[0051] Furthermore, as shown in Figures 6A and 6B, the wire 54 between the pulley 52 and the second moving member 32c is parallel to the axial direction of the rotating guide member 31 in the radial direction of the pulley 52, and as shown in Figure 1A, the pulley 52 and the like are positioned such that the wire 54 is also parallel to the axial direction of the rotating guide member 31 in the axial direction of the bit moving motor 50, which is perpendicular to the radial direction of the pulley 52.

[0052] Furthermore, when the wire 54 is wound around the pulley 52 in multiple layers, the distance from the center of the pulley 52 to the wire 54 changes according to the number of turns, which changes the amount of movement of the driver bit 2 when the pulley 52 rotates once. Also, 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 driver bit 2 along the axial direction of the rotating guide member 31 changes.

[0053] Therefore, the diameter of the pulley 52 is set such that the amount of rotation α of the pulley 52 required to move the driver bit 2 by a predetermined amount is less than 360°.

[0054] As a result, when the pulley 52 winds the wire 54 to move the driver bit 2 by a predetermined amount, the wire 54 is not wound on the pulley 52 in an overlapping manner, as shown in Figure 6B, and inaccuracies in the amount of movement of the driver bit 2 are suppressed. In addition, 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 driver bit 2 along the axial direction of the rotating guide member 31 are suppressed.

[0055] Therefore, the relationship between the rotational speed of the bit movement motor 50 and the amount of movement of the holding member 30 is one-to-one across the entire range of movement of the holding member 30. By controlling the rotational speed of the bit movement motor 50, the amount of movement of the holding member 30 along the axial direction of the rotating guide member 31 can be controlled. In other words, by controlling the rotational speed of the bit movement motor 50, the amount of movement of the driver bit 2 attached to the holding member 30 can be controlled.

[0056] Furthermore, regardless of the amount of wire 54 wound, the tension on the wire 54 is always parallel to the direction of movement of the driver bit 2 along the axial direction of the rotating guide member 31, thereby suppressing a decrease in the efficiency of force transmission for the movement of the driver bit 2 and for pushing the screw 200 through the driver bit 2.

[0057] As a result, the wire 54 between the pulley 52 and the second moving member 32c extends in a straight line along the direction of movement of the moving member 32, suppressing the increase in load when the wire 54 is wound up by the pulley 52 and the increase in load when the wire 54 is pulled out from the pulley 52.

[0058] Furthermore, since the wire 54 is flexible enough to be wound onto the pulley 52, it cannot push the second moving member 32c to move the moving member 32 backward. Therefore, a biasing member 33 is provided that compresses the moving member 32 when it moves forward as indicated by arrow A1, and applies a force to the moving member 32 that pushes it backward as indicated by arrow A2. In this configuration, the wire 54 is wound onto the pulley 52, and the driver bit 2 is advanced, and then the driver bit 2 can be moved backward after it has advanced.

[0059] Furthermore, the retaining member 30 that holds the driver bit 2 is supported so as to be movable in the front-rear direction relative to the rotating guide member 31 by the engagement of a connecting member 30b provided on the retaining member 30 and a groove 31a provided on the rotating guide member 31, and also rotates together with the rotating guide member 31.

[0060] Therefore, with the bit rotation motor 40 positioned coaxially with the rotation guide member 31 and the holding member 30, and the driver bit 2 held by the holding member 30, it is possible to rotate the driver bit 2 and move the driver bit 2 in the front-to-back direction without moving the bit rotation motor 40 in the front-to-back direction.

[0061] In a configuration where the bit rotation motor 40 is positioned coaxially with the driver bit 2, a lead screw can be used to convert the rotational motion of the bit rotation motor 40 into forward and backward movement of the driver bit 2.

[0062] However, in a configuration using a lead screw, the amount of forward movement of the driver bit 2 per motor rotation cannot be large, making it difficult to increase the movement speed of the driver bit 2 even if the motor rotation speed is increased.

[0063] In fastening tool 1, the driver bit 2 needs to move quickly in order to reduce the time it takes to press the screw 200 against the object to be fastened. However, in a configuration using a lead screw, it is difficult to reduce the time it takes for the driver bit 2 to press the screw 200 against the object to be fastened.

[0064] In contrast, in a configuration where the holding member 30 that holds the driver bit 2 is supported so as to be movable in the front-rear direction relative to the rotating guide member 31, and the pulley 52 is rotated by the second drive unit 5 to wind up the wire 54 and move the holding member 30 in the forward direction, the moving speed of the driver bit 2 can be increased according to the rotation speed of the bit moving motor 50. Therefore, the time it takes to press the screw 200 against the object to be fastened with the driver bit 2 can be shortened.

[0065] Figures 7A and 7B are cross-sectional views showing an example of a detachable and retaining mechanism, and Figures 8A and 8B are perspective views showing an example of a detachable and retaining mechanism, illustrating the details of the detachable and retaining mechanism 30c. Next, the detachable and retaining mechanism 30c will be described with reference to each figure.

[0066] The attachment / detachment holding mechanism 30c includes a ball 30d exposed within the opening 30a and a spring 30e that biases the ball 30d in the direction of being exposed within the opening 30a. The spring 30e is made of an annular leaf spring and is fitted around the outer circumference of the holding member 30.

[0067] When the insertion portion 20 of the driver bit 2 is inserted into the opening 30a of the retaining member 30, the attachment / detachment retaining mechanism 30c retracts the ball 30d, which is pressed by the insertion portion 20, towards the outer circumference of the retaining member 30, while deforming the annular spring 30e in a direction that increases the diameter of the spring 30e.

[0068] When the insertion portion 20 of the driver bit 2 is inserted into the opening 30a of the retaining member 30 until the groove 20a formed on the outer circumference of the insertion portion 20 faces the ball 30d, the ball 30d, biased by the spring 30e, fits into the groove 20a. This prevents the driver bit 2 from unintentionally coming out of the retaining member 30.

[0069] Furthermore, if a force greater than a predetermined amount is applied in the direction of removing the driver bit 2 from the retaining member 30, the ball 30d retracts while the annular spring 30e deforms in a direction that increases the diameter of the spring 30e, thereby making it possible to remove the driver bit 2 from the retaining member 30.

[0070] When the insertion portion 20 of the driver bit 2 is inserted into or removed from the opening 30a of the retaining member 30, the ball 30d retracts toward the outer circumference of the retaining member 30. Therefore, a space is required on the outer circumference of the retaining member 30 for the ball 30d to retract. On the other hand, the retaining member 30 is inserted inside the cylindrical rotating guide member 31, and a space for the ball 30d to retract cannot be secured between the outer circumference of the retaining member 30 and the inner circumference of the rotating guide member 31.

[0071] Furthermore, in order to secure space for the ball 30d to retract between the outer circumference of the holding member 30 and the inner circumference of the rotating guide member 31, if a difference in diameter between the holding member 30 and the rotating guide member 31 is set, the outer diameter of the holding member 30 cannot be reduced because the radial dimensions of the driver bit 2 are fixed, and therefore the outer diameter of the rotating guide member 31 must be increased. As a result, the device becomes larger.

[0072] In contrast, the rotating guide member 31 is provided with a groove 31a that guides the connecting member 30b. The groove 31a penetrates the rotating guide member 31 from the inner circumference to the outer circumference and extends in the axial direction of the rotating guide member 31.

[0073] Therefore, the attachment / detachment holding mechanism 30c is provided such that the ball 30d is positioned in accordance with the groove 31a of the rotating guide member 31. That is, the holding member 30, the connecting member 30b and the ball 30d of the attachment / detachment holding mechanism 30c are provided coaxially along the axial direction of the rotating guide member 31. As a result, in the attachment / detachment holding mechanism 30c, whether the rotating guide member 31 and the holding member 30 rotate or the holding member 30 moves axially relative to the rotating guide member 31, the ball 30d is exposed in the groove 31a of the rotating guide member 31.

[0074] Therefore, as the insertion portion 20 of the driver bit 2 is inserted into and removed from the opening 30a of the retaining member 30, the ball 30d, which retracts toward the outer circumference of the retaining member 30, enters the groove 31a of the rotating guide member 31.

[0075] Therefore, with the holding member 30 inserted inside the cylindrical rotating guide member 31, a space can be secured for the ball 30d of the attachment / detachment holding mechanism 30c to retract. In addition, by using the groove 31a into which the connecting member 30b is inserted as a space for the ball 30d to retract, the area of ​​the opening provided in the rotating guide member 31 is reduced, and strength can be ensured.

[0076] Furthermore, by increasing the diameter difference between the holding member 30 and the rotating guide member 31, it becomes unnecessary to secure a space for the ball 30d to recede between the outer circumference of the holding member 30 and the inner circumference of the rotating guide member 31, thereby suppressing the need to increase the size of the device.

[0077] Figure 9 is a perspective view showing an example of the screw feed section and nose section of this embodiment, and details of the screw feed section 7 and nose section 8. Next, the screw feed section 7 and nose section 8 will be described with reference to each figure.

[0078] The screw feed unit 7 comprises a screw feed motor 70, a pinion gear 71 attached to the shaft of the screw feed motor 70 via a reduction gear, a rack gear 72 that meshes with the pinion gear 71, and an engagement part 73 that is connected to the rack gear 72 and engages with the connecting screw fed from the screw storage unit 6.

[0079] In the screw feeding section 7, the rack gear 72 is supported so as to be movable in the vertical direction along the feeding direction of the connecting screw. In the screw feeding section 7, the screw feeding motor 70 rotates in the forward and reverse directions, causing the engaging portion 73 that engages with the connecting screw to move vertically, thereby feeding the connecting screw.

[0080] The nose section 8 is supplied with screws 200 by the screw feeding section 7 and has an injection passage 80 through which the driver bit 2 passes, an injection port 81a communicating with the injection passage 80, a contact member 81 that contacts the object to be fastened, a contact arm 82 that moves in the front-rear direction in conjunction with the contact member 81, and an adjustment section 83 that restricts the amount of movement of the contact arm 82. The nose section 8 also 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.

[0081] The fastening tool 1 has a nose section 8 formed by assembling the components that make up the injection passage 80, contact member 81, and contact arm 82, and is fixed to the front frame 10b and nose body section 10f that make up the tool body 10. The fastening tool 1 also includes a contact switch section 84 that is activated when pressed by the contact arm 82.

[0082] In the nose section 8, the contact member 81 is supported so as to be movable in the front-rear direction indicated by arrows A1 and A2, and the contact arm 82 moves in the front-rear direction in conjunction with the contact member 81. In the nose section 8, the contact member 81 is biased forward by a biasing member (not shown), and the contact member 81, which has moved backward when pressed against the object to be fastened, is then biased forward by the biasing member and moves forward.

[0083] In the nose section 8, the amount of movement of the contact arm 82 until the contact member 81 is pressed against the object to be fastened, causing the contact arm 82 to move backward and the contact switch section 84 to activate is adjusted by the adjustment section 83. The contact switch section 84 is switched on or off by being pressed by the contact arm 82. In this example, the state where the contact switch section 84 is not activated because it is not being pressed by the contact arm 82 is considered the "off" state of the contact switch section 84, and the state where the contact switch section 84 is activated because it is being pressed by the contact arm 82 is considered the "on" state of the contact switch section 84.

[0084] Next, the configuration of the fastening tool 1 for control and operation will be described with reference to the figures. The fastening tool 1 includes a trigger 9 that receives operation and a trigger switch unit 90 that is activated 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 operable with the fingers of the hand gripping the handle 11. The trigger switch unit 90 is activated when pressed by the trigger 9.

[0085] The trigger switch unit 90 is switched on or off when pressed by the trigger 9. In this example, when the trigger 9 is not operated and the trigger switch unit 90 is not pressed by the trigger 9, the trigger switch unit 90 is considered off, and when the trigger 9 is operated and the trigger switch unit 90 is activated by being pressed by the trigger 9, the trigger switch unit 90 is considered on.

[0086] The fastening tool 1 includes a control unit 100 that controls a first drive unit 4, a second drive unit 5, and a screw feed unit 7 based on the output of a trigger switch unit 90 that is operated by the operation of a trigger 9 and a contact switch unit 84 that is operated by being pressed by a contact member 81.

[0087] The control unit 100 is composed of a circuit board on which various electronic components are mounted, and is located between the screw storage section 6 and the handle 11, in a circuit board storage section 111 provided on the back side of the screw storage section 6.

[0088] In power tools that are used by holding the handle by hand, a storage compartment for consumables such as screws is located in front of the handle. Furthermore, in order to allow the handle to be gripped by hand, there needs to be space between the handle and the storage compartment for the fingers to fit.

[0089] Therefore, the fastening tool 1 utilizes the space between the screw storage section 6 and the handle 11 to provide a circuit board storage section 111 on the back side of the screw storage section 6.

[0090] In power tools that are used by holding the handle by hand, a configuration has been proposed in which the battery is attached to the bottom of the handle, and a circuit board is placed between the handle and the battery. With this configuration, the vertical dimension of the power tool along the extension direction of the handle is increased.

[0091] In contrast, by providing a substrate storage section 111 on the back side of the screw storage section 6, the vertical dimension of the fastening tool 1 along the extension direction of the handle 11 is suppressed. Furthermore, since the screw storage section 6 houses spirally wound connecting screws, the surface of the screw storage section 6 facing the handle 11 is approximately circular. This allows for securing the volume of the substrate storage section 111 while suppressing an increase in the size of the fastening tool 1.

[0092] Figures 10A to 10C are rearward perspective views showing an example of a fastening tool according to this embodiment, and Figure 11 is a perspective view showing an example of a setting section, illustrating the details of the setting section 110. Next, the setting section 110 will be described with reference to each figure.

[0093] The fastening tool 1 includes a second drive unit 5 that moves the driver bit 2 in a forward and backward direction along the axial direction. The second drive unit 5 is driven by a bit moving motor 50, and a moving member 32 connected by a wire 54 to a pulley 52 that rotates driven by the bit moving motor 50, and a holding member 30 connected to the moving member 32, move along a rotating guide member 31 in a forward direction along the axial direction of the driver bit 2.

[0094] This allows the amount of movement (advance) of the driver bit 2 to be controlled by controlling the rotation speed of the bit movement motor 50. In other words, by rotating the bit movement motor 50 in conjunction with the rotation of the bit rotation motor 40, which rotates the driver bit 2 in the direction of fastening the screw 200, the amount of advance of the driver bit 2, which moves forward following the screw 200 as the screw 200 is fastened, can be controlled by the rotation speed of the bit movement motor 50, thereby controlling the stopping position of the driver bit 2 along its axial direction.

[0095] Therefore, the fastening tool 1 is equipped with a setting unit 110 for setting the amount of forward movement of the driver bit 2. The setting unit 110 is an example of a setting means, and is configured to allow selection of any setting value from a plurality of setting values, or to allow stepless selection of any setting value.

[0096] In this example, the setting unit 110 is configured such that the setting value is selected by an operation unit 110a consisting of buttons. Alternatively, the operation unit 110a may be configured such that the setting value is selected by a rotary dial. Furthermore, the setting unit 110 may be configured to display the selected setting value so that the operator can easily understand the current setting value, for example by indicating the current value with a label or engraving, or by indicating the current value with a display unit 110b such as an LED.

[0097] The setting section 110 is provided on both the left and right sides of the surface facing the handle 11 in the circuit board storage section 111, which is located on the back side of the screw storage section 6.

[0098] This makes it possible to see the setting section 110 from both the left and right sides of the handle 11 when viewing the fastening tool 1 from the rear.

[0099] In the usage configuration where the handle 11 is held by hand, the side of the screw storage section 6 facing the handle 11 faces the operator holding the fastening tool 1. As a result, by providing the setting section 110 on the side of the circuit board storage section 111 on the back side of the screw storage section 6 that faces the handle 11, the display section 110b provided on the setting section 110 is easily visible. Therefore, the possibility of the operator missing the display is reduced. The information displayed on the display section 110b includes the setting value of the screw depth defined by the amount the driver bit 2 advances, the ON / OFF status of the power, the operating mode selected from the various selectable operating modes, the presence or absence of screws, the remaining amount of screws, and whether or not there is an abnormality.

[0100] Furthermore, when using the device with the handle 11 held in the hand, the operating section 110a, such as buttons, on the setting section 110 is easily visible. Therefore, while holding the handle 11 with one hand, the user can see the operating section 110a and operate it with the other hand, ensuring reliable operation.

[0101] Furthermore, the circuit board housing section 111 houses the circuit board that constitutes the control unit 100. By mounting switches and other components that constitute the operation section 110a and lamps and other components that constitute the display section 110b on the side of this circuit board facing the handle 11, a separate circuit board for the setting section 110 can be omitted in addition to the control unit 100.

[0102] Figure 12 is a block diagram showing an example of a fastening tool according to this embodiment. As described above, the fastening tool 1 includes a second drive unit 5 that moves the driver bit 2 in a forward and backward direction along the axial direction, and the second drive unit 5 is driven by a bit moving motor 50. The holding member 30 to which the driver bit 2 is attached is connected to a moving member 32, and the moving member 32 is connected by a wire 54 to a pulley 52 that rotates driven by the bit moving motor 50. The holding member 30 and the moving member 32 are configured to move forward along the axial direction of the driver bit 2 along the rotating guide member 31.

[0103] As a result, the control unit 100 can control the amount of movement (advance) of the driver bit 2 by controlling the rotation speed of the bit movement motor 50. In other words, by rotating the bit movement motor 50 in conjunction with the rotation of the bit rotation motor 40, which rotates the driver bit 2 in the direction of fastening the screw 200, the amount of advance of the driver bit 2, which moves forward following the screw 200 as the screw 200 is fastened, can be controlled by the rotation speed of the bit movement motor 50, thereby controlling the stopping position of the driver bit 2 along its axial direction.

[0104] Furthermore, the control unit 100 sets the rotation speed of the bit movement motor 50, which defines the amount of forward movement of the driver bit 2, in the setting unit 110. In addition, the control unit 100 controls whether or not to drive 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 the combination of on / off states of the contact switch unit 84 and the trigger switch unit 90.

[0105] <Example of operation of the fastening tool in this embodiment> Figure 13A is a side cross-sectional view showing an example of the operation of the fastening tool of this embodiment, Figure 13B is a top cross-sectional view showing an example of the operation of the fastening tool of this embodiment, and Figure 14 is a flowchart showing an example of the operation of the fastening tool of this embodiment. Next, the fastening operation of the fastening tool of this embodiment will be described with reference to each figure.

[0106] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0107] In step SA1 of Figure 14, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 is turned on in step SA2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SA3, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SA4, and drives the bit movement motor 50 of the second drive unit 5 in step SA5.

[0108] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52. ​​As the wire 54 is wound onto the pulley 52, the second moving member 32c, which is connected to the wire 54, is guided by the rotating guide member 31 and moves forward along the axial direction. As the second moving member 32c moves forward, the first moving member 32a is pushed by the second moving member 32c via the bearing 32b, and together with the second moving member 32c, it moves forward along the axial direction while compressing the biasing member 33.

[0109] When the first movable member 32a moves forward, the holding member 30, which is connected to the first movable member 32a by the connecting member 30b, moves forward along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove 31a of the rotating guide member 31.

[0110] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0111] Furthermore, when the bit rotation motor 40 is driven and rotates 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, which is connected to the holding member 30, is pressed against the groove 31a of the rotation guide member 31, causing the holding member 30 to rotate together with the rotation guide member 31.

[0112] This causes the driver bit 2 held by the holding member 30 to rotate the screw 200 in the forward direction (clockwise) and screw it into the object to be fastened. The control unit 100, in conjunction with the operation of the first drive unit 4 to rotate the driver bit 2 and screw the screw into the object to be fastened, moves the driver bit 2 forward with the second drive unit 5 based on the load on the bit rotation motor 40, the rotation speed of the bit rotation motor 40, the load on the bit movement motor 50, the rotation speed of the bit movement motor 50, etc., thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened. In this embodiment, the load on the bit rotation motor 40, etc. is the force based on resistance, including frictional force, that occurs between the screw 200 and the object to be fastened when the screw 200 is screwed into the object to be fastened.

[0113] 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, and that the tip of the driver bit 2 has reached the set operation end position P2, as shown in Figures 13A and 13B. In step SA7, it stops driving the bit rotation motor 40, and in step SA8, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SA9, it reverses the bit movement motor 50.

[0114] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, causing the wire 54 to be pulled out from the pulley 52. ​​As the wire 54 is pulled out from the pulley 52, the second moving member 32c moves forward, causing the compressed biasing member 33 to expand and push the second moving member 32c backward.

[0115] The second moving member 32c is pushed backward by the biasing member 33, guided by the rotating guide member 31, and moves backward along the axial direction. As the second moving member 32c moves backward, the first moving member 32a is pulled by the second moving member 32c via the bearing 32b, and moves backward along the axial direction together with the second moving member 32c.

[0116] When the first movable member 32a moves in the rearward direction, the holding member 30, which is connected to the first movable member 32a by the connecting member 30b, moves in the rearward direction along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove 31a of the rotating guide member 31.

[0117] In step SA10, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SA11.

[0118] Furthermore, the movable member 32 is equipped with a cushioning member 32d made of rubber or the like on the rear side of the second movable member 32c, so that when the second movable member 32c moves in the rearward direction, it is suppressed that the second movable member 32c directly hits the rear frame 10c, thereby suppressing the generation of noise and damage. When the trigger switch unit 90 is turned off, the control unit 100 rotates the screw feed motor 70 in one direction to lower the engaging part 73. When the engaging part 73 has lowered to a position where it engages with the next screw 200, the control unit 100 reverses the screw feed motor 70 to raise the engaging part 73 and supply the next screw 200 to the injection passage 80.

[0119] Figures 15A to 15C are cross-sectional views showing the fastening state of the screw. Figure 15A shows the so-called flush state where the head 201 of the screw 200 is neither raised nor embedded in the surface of the object 202 to be fastened. Figure 15B shows the state where the head 201 of the screw 200 is raised from the object 202 to be fastened. Figure 15C shows the state where the head 201 of the screw 200 is embedded in the object 202 to be fastened.

[0120] In fastening tools 1, when the tip of the driver bit 2 reaches the end position P2, if the screw 200 is a countersunk screw, it is preferable that the amount of advancement of the driver bit 2 is set so that the surface of the head 201 of the screw 200 becomes flush with the surface of the object to be fastened 202, as shown in Figure 15A. Note that the screw 200 is not limited to countersunk screws; if it is a pan head, bind screw, truss screw, etc., it is preferable that the amount of advancement of the driver bit 2 is set so that the seating surface of the head 201 of the screw 200 is in contact with the surface of the object to be fastened 202, and the head 201 of the screw 200 does not float away from the object to be fastened 202.

[0121] When the tip of the driver bit 2 reaches the end position P2, if the head 201 of the screw 200 is floating above the object to be fastened 202 as shown in Figure 15B, the amount of movement (advance) of the driver bit 2 is set in the setting unit 110, and the amount of advance of the driver bit 2 is increased by increasing the rotation speed (rotation amount) of the bit movement motor 50, thereby advancing the end position P2. On the other hand, if the head 201 of the screw 200 is embedded in the object to be fastened 202 as shown in Figure 15C, the amount of movement (advance) of the driver bit 2 is set in the setting unit 110, and the amount of advance of the driver bit 2 is decreased by decreasing the rotation speed of the bit movement motor 50, thereby retracting the end position P2.

[0122] As described above, the amount of movement (advance) of the driver bit 2 is determined by the rotation speed of the bit movement motor 50. Starting from the standby position P1, which is the initial position of the driver bit 2, the bit movement motor 50 is rotated by the rotation speed set by the setting unit 110, and then the operation end position P2 is controlled by stopping or reversing the rotation of the bit movement motor 50. Thus, the tightening depth can be adjusted.

[0123] In this manner, in order to enable the tip position of the driver bit 2 held by the holding member 30 to advance by a predetermined amount based on the rotational speed of the bit moving motor 50 with respect to a predetermined standby position P1, standby positions are set for the holding member 30 to which the driver bit 2 is attached and the moving member 32 that moves the holding member 30. The operation of setting the standby positions of the holding member 30 and the moving member 32 is referred to as the first initialization operation.

[0124] Then, before the driving and fastening operation begins, the holding member 30 and the moving member 32 are moved to a set standby position, and the positions of the holding member 30 and the moving member 32 are controlled by the rotation speed of the bit moving motor 50 with respect to the standby position. Then, the holding member 30 and the moving member 32 are moved forward from the set standby position to a predetermined amount of movement (advance) and the fastening operation is performed. The operation of moving the holding member 30 and the moving member 32 to the standby position set in the first initialization operation is called the second initialization operation.

[0125] Possible means for setting the standby positions of the holding member 30 and the moving member 32 in the first initialization operation include using a sensor or using the maximum position within the range of forward and backward movement of the holding member 30 and the moving member 32 as a reference. When using a sensor, the standby position is set to the position detected by the sensor or a position moved by a specified amount from the detection position.

[0126] Furthermore, when using the maximum position within the range of forward and backward movement, the holding member 30 and the moving member 32 are set to a standby position at a position moved by a specified amount from the front end position or the rear end position.

[0127] Figures 16A to 16D are explanatory diagrams showing an example of the operation to set the standby positions of the holding member and the moving member in the first initialization operation. Next, the operation to set the standby positions of the holding member 30 and the moving member 32 will be explained. In Figures 16A to 16D, the standby positions are set using the maximum position within the forward and backward movement range of the holding member 30 and the moving member 32.

[0128] As shown in Figure 16A, the control unit 100 rotates the bit moving motor 50 in the forward direction, which is one direction, from a state where the holding member 30 and the moving member 32 are in any position. When the bit moving motor 50 rotates forward, the wire 54 is wound onto the pulley 52, causing the moving member 32 and the holding member 30 connected to the moving member 32 to move forward along the rotation guide member 31 in the axial direction of the driver bit 2.

[0129] As shown in Figure 16B, when the bit movement motor 50 rotates forward until the holding member 30 and the moving member 32 have moved to the front end position PF, which is one end position, the control unit 100 stops the forward rotation of the bit movement motor 50 and moves the holding member 30 and the moving member 32 to the front end position PF.

[0130] Next, the control unit 100 rotates the bit moving motor 50 in the opposite direction. When the bit moving motor 50 reverses direction, the wire 54 is pulled out from the pulley 52, causing the biasing member 33 to push the moving member 32 backward, and the moving member 32 and the holding member 30 connected to the moving member 32 move backward along the rotating guide member 31, along the axial direction of the driver bit 2.

[0131] As shown in Figure 16C, when the bit movement motor 50 reverses direction until the holding member 30 and the moving member 32 have moved to the rear end position PE, which is the other end position, the control unit 100 stops the reverse direction of the bit movement motor 50 and moves the holding member 30 and the moving member 32 to the rear end position PE by the biasing force of the biasing member 33.

[0132] The control unit 100 acquires the amount of movement of the holding member 30 and the moving member 32 from the front end position PF to the rear end position PE as the total distance L1. The amount of movement from the front end position PF to the rear end position PE is determined from the rotational speed of the bit moving motor 50.

[0133] The control unit 100 pre-sets the amount of movement of the holding member 30 and the moving member 32 from their standby positions to the front end position PF as the target movement amount L2. The control unit 100 sets the difference between the total distance L1 from the front end position PF to the rear end position PE and the pre-set target movement amount L2 as the standby position movement amount L3 and stores it. The standby position movement amount L3 is the amount of movement of the holding member 30 and the moving member 32 from the rear end position PE.

[0134] As shown in Figure 16D, the control unit 100 rotates the bit movement motor 50 in the forward direction, moving the holding member 30 and the moving member 32 forward from the rear end position PE. When the control unit 100 rotates the bit movement motor 50 in the forward direction for a number of rotations corresponding 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 tip of the driver bit 2 held by the holding member 30 to the standby position P1.

[0135] Furthermore, when moving the holding member 30 and the moving member 32 to the front end position PF and the rear end position PE, it is desirable to drive them at a low speed such as when the second moving member 32c comes into contact with the cushioning member 32d, so as not to affect the durability of the tool.

[0136] Figures 17A to 17C are explanatory diagrams showing an example of the operation to move the holding member and the moving member to the standby position in the second initialization operation. Next, the operation to move the holding member 30 and the moving member 32 to a predetermined standby position will be explained.

[0137] As shown in Figure 17A, the control unit 100 rotates the bit moving 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 moving motor 50 reverses direction, the wire 54 is pulled out from the pulley 52, and the biasing member 33 pushes the moving member 32 backward. As a result, the moving member 32 and the holding member 30 connected to the moving member 32 move backward along the rotating guide member 31, along the axial direction of the driver bit 2.

[0138] As shown in Figure 17B, when the bit movement motor 50 reverses direction until the holding member 30 and the moving member 32 move to the rear end position PE, the control unit 100 stops the reverse direction of the bit movement motor 50 and moves the holding member 30 and the moving member 32 to the rear end position PE by the biasing force of the biasing member 33.

[0139] As shown in Figure 17C, the control unit 100 rotates the bit movement motor 50 in the forward direction, moving the holding member 30 and the moving member 32 forward from the rear end position PE. When the control unit 100 rotates the bit movement motor 50 in the forward direction for a number of rotations corresponding 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 tip of the driver bit 2 held by the holding member 30 to the standby position P1.

[0140] In the first initialization operation described in Figures 16A to 16D, the operation to set the standby positions of the holding member 30 and the moving member 32 is performed at the factory, for example, when the product is shipped, without user intervention, and the standby position movement amount L3 is stored in advance.

[0141] On the other hand, in the second initialization operation described in Figures 17A to 17C, the operation to move 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 fastening tool 1 is powered on, in order to enable stable fastening operation.

[0142] Therefore, the system is configured to allow selection between a first initialization operation and a second initialization operation, which are initialization operations related to the standby positions of the holding member 30 and the moving member 32.

[0143] Figure 18 is a flowchart showing an example of the process of selecting between a first initialization operation and a second initialization operation.

[0144] When the power is turned on in step SB1 of Figure 18, the control unit 100 selects an initialization operation to be performed in step SB2. If the control unit 100 selects to perform the first initialization operation, in step SB3 it performs the first initialization operation described in Figures 16A to 16D above to set the standby positions of the holding member 30 and the movable member 32. If the control unit 100 selects to perform the second initialization operation, in step SB4 it performs the second initialization operation described in Figures 17A to 17C above to move the holding member 30 and the movable member 32 to the standby position based on the standby position movement amount L3. After performing the second initialization operation, the control unit 100 performs a normal fastening operation in step SB5 according to the flowchart in Figure 14 above.

[0145] As described above, in the first initialization operation, the holding member 30 and the moving member 32 are moved at a low speed from the front end position PF to the rear end position PE to obtain the total distance L1 from the front end position PF to the rear end position PE. The amount of movement from the rear end position PE is determined so that the amount of movement from the front end position PF becomes a predetermined target amount L2, and this amount of movement is set as the standby position movement amount L3 and recorded in the memory on a circuit board (not shown) that constitutes the control unit 100. This eliminates various machine variations, such as dimensional differences within tolerances, and allows the standby positions of the holding member 30 and the moving member 32 to be set to a constant position, for example, from the front end position PF.

[0146] Furthermore, in the second initialization operation, each time the power is turned on for use by the user, the holding member 30 and the moving member 32 are moved from the rear end position PE to the standby position according to the amount of movement L3, thereby minimizing the amount of movement of the holding member 30 and the moving member 32. Moreover, in the second initialization operation, the tip of the driver bit 2 is located at the standby position P1 behind the injection passage 80, and the second initialization operation can be performed with the screw 200 supplied to the injection passage 80.

[0147] As described above, the amount of movement (advancement) of the driver bit 2 is determined by the rotational speed of the bit movement motor 50, starting from the standby positions of the holding member 30 and the moving member 32, i.e., the standby position P1 of the driver bit 2. Therefore, if the standby positions of the holding member 30 and the moving member 32, i.e., the standby position P1 of the driver bit 2, vary, the tightening depth set in the setting unit 110 will vary.

[0148] In contrast, by performing a second initialization operation each time the power is turned on, the bit movement motor 50 is rotated by the number of rotations set in the setting unit 110, starting from the standby position of the holding member 30 and the moving member 32, i.e., the standby position P1 of the driver bit 2, thereby enabling precise adjustment of the screw tightening depth.

[0149] Figure 19 is a flowchart showing a modified operation of the fastening tool of this embodiment, and Figure 20 is a graph showing the relationship between the output of the contact switch unit and the control of the bit rotation motor and bit movement motor. Next, other examples of the fastening operation of the fastening tool of this embodiment will be described with reference to each figure. In this modified example, the output of the contact switch unit 84 is used to detect whether or not the fastening tool 1 is lifting off the object to be fastened, and the bit rotation motor 40 and bit movement motor 50 are controlled accordingly.

[0150] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0151] In step SC1 of Figure 19, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 turns on in step SC2, the trigger 9 is operated, and the trigger switch unit 90 turns on in step SC3. In step SC4, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4, and in step SC5, it drives the bit movement motor 50 of the second drive unit 5.

[0152] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52, and the second moving member 32c moves forward, along with the moving member 32 connected to the wire 54 and the holding member 30 connected to the moving member 32 by the first moving member 32a.

[0153] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0154] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0155] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the object to be fastened. The control unit 100, in conjunction with the operation of the first drive unit 4 to rotate the driver bit 2 and screw the screw into the object to be fastened, moves the driver bit 2 forward with the second drive unit 5 based on the load on the bit rotation motor 40, the rotation speed of the bit rotation motor 40, the load on the bit movement motor 50, the rotation speed of the bit movement motor 50, etc., thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0156] In step SC6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2, and in step SC7, it stops driving the bit movement motor 50.

[0157] In step SC7, the control unit 100 stops driving the bit movement motor 50, and in step SC8, it determines whether the contact switch unit 84 is ON. If the contact switch unit 84 is ON, the control unit 100 determines that the fastening tool 1 is not lifting away from the object to be fastened, and in order to terminate the fastening operation, it stops the rotation of the bit rotation motor 40 in the forward direction in step SC9 and reverses the bit movement motor 50 in step SC10.

[0158] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0159] In step SC11, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SC12.

[0160] In step SC8, the control unit 100 determines that if the contact switch unit 84 is off, the fastening tool 1 is floating away from the object to be fastened, and stops the bit movement motor 50 while continuing to rotate the bit rotation motor 40 in the forward direction.

[0161] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction and screws it further into the object to be fastened, causing the fastening tool 1 to move in a direction closer to the object to be fastened. Therefore, the fastening tool 1 moves relative to the contact arm 82, and the contact arm 82 pushes the contact switch unit 84, turning on the contact switch unit 84. When the contact switch unit 84 is on, the control unit 100 terminates the fastening operation by executing the processes of steps SC9 to SC12 described above, stopping the bit rotation motor 40 and returning the driver bit 2 to the standby position by reversing the bit movement motor 50.

[0162] Furthermore, while the contact switch unit 84 is turned off and the bit movement motor 50 is stopped, the control unit 100 performs a control called a braking operation to prevent the bit movement motor 50 from rotating due to external force during the operation of rotating the bit rotation motor 40 in the forward direction, thereby maintaining the holding member 30 and the moving member 32, and the driver bit 2 held by the holding member 30, in a stopped state at the operation end position P2.

[0163] However, while the bit movement motor 50 is stopped, and the bit rotation motor 40 is rotating in the forward direction, the fastening tool 1 is subjected to force applied by the operator in a direction that presses it against the object to be fastened, while the screw 200 is being tightened. Therefore, even if a braking operation is performed on the bit movement motor 50, the force applied by the operator may cause the holding member 30, the moving member 32, and the driver bit 2 held by the holding member 30 to move backward from the operation end position P2.

[0164] Therefore, in step SC13, the control unit 100 detects whether the bit movement motor 50 is rotating in reverse. If it detects that the bit movement motor 50 is rotating in reverse, it returns to step SC5, rotates the bit movement motor 50 in the forward direction, moves the holding member 30 and the moving member 32 forward, and returns the driver bit 2 to the operation end position P2. Then, it stops the forward rotation of the bit movement motor 50 and performs a braking operation.

[0165] Furthermore, for the contact arm 82 to switch the contact switch unit 84 on and off, the contact arm 82 needs to move by a predetermined amount. For this reason, as described above, in step SC8, when it is detected that the contact switch unit 84 is off and the bit moving motor 50 is stopped, the bit rotating motor 40 is continued to rotate in the forward direction, and while the contact arm 82 moves until the contact switch unit 84 switches from off to on, the positions of the holding member 30 and the moving member 32 may change. Therefore, it is desirable to provide a detection unit that detects the position of the contact arm 82. Alternatively, the rotation of the bit holding unit 3 and the axial movement of the bit holding unit 3 may be performed by a single motor, and the control unit 100 may control the timing of stopping the drive of the single motor based on whether or not the contact switch unit 84 is operating as described above.

[0166] Figure 21 is a flowchart showing other variations of the operation of the fastening tool of this embodiment, and Figures 22A and 22B are graphs showing the relationship between the load and the control of the bit rotation motor. Next, other variations of the fastening operation of the fastening tool of this embodiment will be described with reference to each figure. In this variation, the load on the bit rotation motor 40 is detected and the bit rotation motor 40 is controlled.

[0167] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0168] In step SD1 of Figure 21, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 turns on in step SD2, the trigger 9 is operated, and the trigger switch unit 90 turns on in step SD3. In step SD4, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4, and in step SD5, it drives the bit movement motor 50 of the second drive unit 5.

[0169] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52, and the second moving member 32c moves forward, along with the moving member 32 connected to the wire 54 and the holding member 30 connected to the moving member 32 by the first moving member 32a.

[0170] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0171] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0172] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the object to be fastened. The control unit 100, in conjunction with the operation of the first drive unit 4 to rotate the driver bit 2 and screw the screw into the object to be fastened, moves the driver bit 2 forward with the second drive unit 5 based on the load on the bit rotation motor 40, the rotation speed of the bit rotation motor 40, the load on the bit movement motor 50, the rotation speed of the bit movement motor 50, etc., thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0173] In step SD6, 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 driver bit 2 has reached the set operation 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 SD7, it detects the load on the bit rotation motor 40, and if a predetermined load is detected, it controls the bit rotation motor 40 in step SD8.

[0174] The rotation speed of the driver bit 2 varies depending on the magnitude of the load on the bit rotation motor 40. If the current and voltage values ​​applied to the bit rotation motor 40 are the same, the higher the load on the bit rotation motor 40, the lower the rotation speed. Therefore, the control unit 100, acting as a fluctuation detection unit to detect factors that cause fluctuations in the rotation speed of the bit rotation motor 40, detects the load on the bit rotation motor 40 and reduces the output of the bit rotation motor 40 by lowering the voltage value applied to the bit rotation motor 40 or lowering the current value flowing through the bit rotation motor 40 compared to when the load is high, as the load on the bit rotation motor 40 is lower. For example, a threshold value may be set in advance to serve as a criterion for determining the magnitude of the load. If the detected load on the bit rotation motor 40 is greater than or equal to the threshold value, the control unit may control the bit rotation motor 40 to lower the voltage value, current value, or output, and if the detected load on the bit rotation motor 40 is less than the threshold value, the control unit may control the bit rotation motor 40 to increase the voltage value, current value, or output.

[0175] As a result, when the load on the bit rotation motor 40 is low, the rotation speed of the bit rotation motor 40 is reduced, which suppresses the increase in rotation speed compared to when the load is high, and thus suppresses differences in the rotation speed of the bit rotation motor 40 depending on the magnitude of the load on the bit rotation motor 40. Therefore, variations in the speed at which the screws 200 are fastened are suppressed.

[0176] In step SD6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SD9, it stops driving the bit rotation motor 40, and in step SD10, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SD11, it reverses the bit movement motor 50.

[0177] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0178] In step SD12, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SD13.

[0179] In the control that reduces the output of the bit rotation motor 40, as shown in Figure 22A, the output may be reduced to maintain a constant rotational speed until the bit rotation motor 40 rotates to the number of rotations required for the driver bit 2 to move to the end of operation position after a predetermined load has been detected. Alternatively, as shown in Figure 22B, the output may be gradually reduced until the bit rotation motor 40 rotates to the number of rotations required for the driver bit 2 to move to the end of operation position after a predetermined load has been detected, so as to reach a target rotational speed.

[0180] Furthermore, fluctuations in the power supply voltage cause differences in the rotation speed of the driver bit 2, with the rotation speed decreasing as the power supply voltage decreases. Therefore, the control unit 100, acting as a fluctuation detection unit to detect the factors causing fluctuations in the rotation speed of the bit rotation motor 40, detects the power supply voltage and reduces the output of the bit rotation motor 40 compared to the case where the power supply voltage is low, as the higher the power supply voltage.

[0181] As a result, when the power supply voltage is high, the rotation speed of the bit rotation motor 40 is reduced compared to when the power supply voltage is low, thereby suppressing differences in the rotation speed of the bit rotation motor 40 caused by fluctuations in the power supply voltage. Therefore, variations in the speed at which the screws 200 are fastened are suppressed.

[0182] Furthermore, the control unit 100 may also set a target rotation speed for the bit rotation motor 40, detect the rotation speed of the bit rotation motor 40, compare the detected rotation speed with the preset target rotation speed of the bit rotation motor 40, and control the bit rotation motor 40 to achieve the target rotation speed.

[0183] Now, reducing the rotation speed of the bit rotation motor 40 will reduce the speed at which screws are fastened to the object. On the other hand, during the stopping process of the bit rotation motor 40 after the screws have been tightened to the target screw tightening depth set in the setting unit 110, the screw is tightened into the object by the driver bit 2 rotating until the rotation of the bit rotation motor 40 has completely stopped. Therefore, the faster the rotation speed of the bit rotation motor 40 just before it stops rotating, the more the screws will be tightened beyond the target.

[0184] Thus, the factor that reduces the quality of screw tightening work due to differences in the rotational speed of the bit rotating motor 40 is the rotational speed of the bit rotating motor 40 just before it stops rotating. Therefore, the desired effect can be obtained if the rotational speed of the bit rotating motor 40 is constant, excluding the influence of the load, just before the amount of movement (advance) of the holding member 30 and the moving member 32 reaches the target screw tightening depth set in the setting unit 110.

[0185] The load on the bit rotation motor 40 increases when the screw is tightened into the object to be fastened, but the load varies depending on the material of the object to be fastened. Therefore, after the load detection described above for controlling the rotation speed of the bit rotation motor 40, the rotation speed of the bit rotation motor 40 is controlled based on the load, power supply voltage, etc., until the target screw tightening depth is reached.

[0186] Furthermore, the control unit 100 may be equipped with a timing unit and, after a predetermined time has elapsed since the start of driving (forward rotation) the bit rotation motor 40, perform the above-described control of the rotation speed of the bit rotation motor 40 based on the load, power supply voltage, etc. Alternatively, the control unit 100 may be equipped with a position detection unit that detects 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, perform the above-described control of the rotation speed of the bit rotation motor 40 based on the load, power supply voltage, etc. The predetermined positions of the holding member 30 and the moving member 32 for performing the rotation speed control of the bit rotation motor 40 are set between the position where the above-described load for controlling the rotation speed of the bit rotation motor 40 is detected and the position where the target screw tightening depth is reached.

[0187] Furthermore, in the method of setting a target rotational speed of the bit rotation motor 40 and controlling its output, it is possible that the target screw tightening depth may be reached before the rotational speed of the bit rotation motor 40 decreases to the target rotational speed due to the influence of the length of the control implementation section, etc. Therefore, braking control of the bit rotation motor 40 may be performed during the control to reduce the rotational speed of the bit rotation motor 40 to the target rotational speed. For example, if the deviation between the target rotational speed of the bit rotation motor 40 and the detected actual rotational speed is large, braking control of the bit rotation motor 40 may be performed until the deviation between the actual rotational speed and the target rotational speed falls within a specified range, and once the deviation falls within the specified range, control may be performed to reduce the rotational speed of the bit rotation motor 40 to the target rotational speed.

[0188] Furthermore, once the driver bit 2 reaches the target screw tightening depth, if the engagement between the driver bit 2 and the screw is released, the screw will not be tightened any further even if the driver bit 2 rotates. Therefore, after the driver bit 2 has advanced to reach the target screw tightening depth, the bit movement motor 50 may be reversed before the rotation of the bit rotation motor 40 stops. In addition, the rotation of the bit holding part 3 and the axial movement of the bit holding part 3 may be performed by a single motor, and the control unit 100 may detect factors that cause fluctuations in the rotation speed of the single motor, such as the load on the motor, and control the motor accordingly.

[0189] Figure 23 is a flowchart showing another modification of the operation of the fastening tool of this embodiment, Figure 24A is a graph showing the relationship between the rotational speeds of the bit rotation motor and the bit movement motor by feedback (FB) control, and Figure 24B is a graph showing the relationship between the screw movement speed by the rotation of the bit rotation motor and the driver bit movement speed by the bit movement motor by feedback (FB) control. Next, other modifications of the fastening operation of the fastening tool of this embodiment will be described with reference to each figure. In this modification, the screw movement speed by the rotation of the bit rotation motor 40 and the driver bit movement speed by the bit movement motor 50 are synchronized by feedback control.

[0190] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0191] In step SE1 of Figure 23, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 turns on in step SE2, the trigger 9 is operated, and the trigger switch unit 90 turns on in step SE3. In step SE4, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4, and in step SE5, it drives the bit movement motor 50 of the second drive unit 5.

[0192] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52, and the second moving member 32c moves forward, along with the moving member 32 connected to the wire 54 and the holding member 30 connected to the moving member 32 by the first moving member 32a.

[0193] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0194] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0195] As a result, the driver bit 2 held by the retaining member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the object to be fastened. The control unit 100 moves the driver bit 2 forward with the second drive unit 5 in conjunction with the operation of rotating the driver bit 2 with the first drive unit 4 to screw the screw into the object to be fastened, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0196] 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 driver bit 2 has reached the set operation 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 SE7, it detects the load on the bit movement motor 50, and if 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.

[0197] In step SE9, the control unit 100 calculates a target rotational speed for the bit moving motor 50 based on the gear ratio of the bit moving motor 40's reducer and the rotational speed of the bit moving motor 40, or calculates a target rotational speed for the bit moving motor 40 based on the gear ratio of the bit moving motor 40's reducer and the rotational speed of the bit moving motor 40, such that the speed at which the screw 200 moves forward when it is fastened to the object by the rotation of the bit moving motor 40, and the speed at which the holding member 30 and moving member 32 move forward by the rotation of the bit moving motor 50, and the driver bit 2 attached to the holding member 30, are approximately the same as shown in Figure 24B.

[0198] In step SE10, the control unit 100 controls the bit moving motor 50 using feedback control based on the target rotational speed of the bit rotating motor 40, the target rotational speed of the bit moving motor 50, the gear ratio of the reduction gear, etc. In this example, it controls the bit moving motor 50 by adjusting its rotational speed by increasing or decreasing the PWM output to the bit moving motor 50.

[0199] In step SE6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SE11, it stops driving the bit rotation motor 40, and in step SE12, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SE13, it reverses the bit movement motor 50.

[0200] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0201] In step SE14, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SE15.

[0202] The feedback control described above is necessary after the object to be fastened and the screw 200 come into contact, causing a change in the load on the bit rotation motor 40 and the bit movement motor 50. Therefore, the control when feedback control is not performed is designated as the first control mode, and the control when feedback control is performed is designated as the second control mode. The first control mode is executed before a predetermined load is detected by either the bit rotation motor 40 or the bit movement motor 50, or both. When a predetermined load is detected by either the bit rotation motor 40 or the bit movement motor 50, or both, the first control mode is switched to the second control mode, and the second control mode is executed. This helps to suppress delays in work time.

[0203] Furthermore, as a means of improving the responsiveness of feedback control and achieving more stable work quality, the acceleration / deceleration limit values ​​for the bit movement motor 50 may be changed between when feedback control is performed after load detection and when feedback control is not performed before load detection. Normally, when a PWM output is applied to a motor, control is performed to stabilize the motor output by limiting the amount of acceleration per unit time, especially to prevent the acceleration current at startup from becoming excessive. However, if the above-mentioned feedback control is performed while the acceleration limit at startup is applied to the bit movement motor 50, the PWM output generated by the feedback control will be limited and applied to the bit movement motor 50, resulting in poor responsiveness to the feedback control. Therefore, it is desirable to set the acceleration limit amount to be larger during the execution of feedback control than during motor startup when feedback control is not performed.

[0204] Figure 25 is a flowchart showing another modification of the operation of the fastening tool of this embodiment, and Figures 26A and 26B are graphs showing the relationship between the load and the control of the bit movement motor. Next, other modifications of the fastening operation of the fastening tool of this embodiment will be described with reference to each figure. In this modification, the load on the bit movement motor 50 is detected and the bit movement motor 50 is controlled.

[0205] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0206] In step SF1 of Figure 25, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact switch unit 84 is pressed by the contact arm 82, the contact switch unit 84 is turned on in step SF2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SF3, 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.

[0207] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52, and the second moving member 32c moves forward, along with the moving member 32 connected to the wire 54 and the holding member 30 connected to the moving member 32 by the first moving member 32a.

[0208] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0209] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0210] As a result, the driver bit 2 held by the retaining member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the object to be fastened. The control unit 100 moves the driver bit 2 forward with the second drive unit 5 in conjunction with the operation of rotating the driver bit 2 with the first drive unit 4 to screw the screw into the object to be fastened, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0211] In step SF6, 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 driver bit 2 has reached the set operation 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 SF7, it detects the load on the bit movement motor 50, and if a predetermined load is detected, it controls the bit movement motor 50 in step SF8.

[0212] When the bit moving motor 50 drives the holding member 30 and the moving member 32 to move forward, pressing the screw 200 against the object to be fastened, in order to suppress the generation of excessive impact and to avoid reducing the fastening speed, the bit rotating motor 40 is operated at the maximum output within the expected range, and the output of the bit moving motor 50 is limited by lowering the voltage value applied to the bit moving motor 50, lowering the current value flowing through the bit moving motor 50, etc.

[0213] If the ratio of the amount the driver bit 2 advances per revolution of the bit moving motor 50 to the amount the screw advances per revolution of the bit rotating motor 40 is low, the amount the driver bit 2 advances due to the bit moving motor 50 will not keep up with the amount the screw advances due to the bit rotating motor 40, causing cam-out. On the other hand, if the ratio of the amount the driver bit 2 advances per revolution of the bit moving motor 50 to the amount the screw advances per revolution of the bit rotating motor 40 is high, the amount the driver bit 2 advances due to the bit moving motor 50 will greatly exceed the amount the screw advances due to the bit rotating motor 40, requiring the operator to apply excessive force to press the fastening tool 1 toward the object to be fastened.

[0214] Therefore, as a target value for output limiting, it is preferable that the ratio of the amount the driver bit 2 advances per rotation of the bit moving motor 50 to the amount the screw advances per rotation of the bit rotating motor 40 is approximately 0.8 to 5 times. This suppresses the occurrence of cam-out and prevents excessive impact when the screw 200 is pressed against the object to be fastened, without requiring excessive force from the operator to press the fastening tool 1 toward the object to be fastened.

[0215] Furthermore, by detecting the load on the bit movement motor 50 that occurs after contact between the object to be fastened and the screw 200, the output of the bit movement motor 50 is limited. This reduces the speed of the holding member 30 and the moving member 32 when the screw 200 is pressed against the object to be fastened, thereby providing a further impact suppression effect.

[0216] In the control that limits the output of the bit movement motor 50, as shown in Figure 26A, after a predetermined load is detected, the output of the bit movement motor 50 may be limited to maintain a constant rotational speed until the bit rotation motor 40 rotates to the number of rotations required for the driver bit 2 to move to the end of operation position. Alternatively, as shown in Figure 26B, the bit movement motor 50 is rotated forward at a first rotational speed until a predetermined load is detected. After the predetermined load is detected, the bit movement motor 50 is rotated forward at a second rotational speed, which is lower in order to reduce the impact when the screw 200 is pressed against the object to be fastened. Furthermore, after a predetermined buffering time has elapsed for the impact when the screw 200 is pressed against the object to be fastened to weaken, the output may be limited to maintain a constant rotational speed at a third rotational speed, which is slower than the first rotational speed and faster than the second rotational speed, until the bit rotation motor 40 rotates to the number of rotations required for the driver bit 2 to move to the end of operation position.

[0217] Furthermore, fluctuations in the power supply voltage can cause differences in the movement speed (forward speed) of the holding member 30 and the moving member 32. The higher the power supply voltage, the faster the movement speed, and the more likely it is that excessive impact will occur when the screw 200 is pressed against the object to be fastened. Therefore, the control unit 100 detects the power supply voltage and reduces the output of the bit moving motor 50 compared to the case where the power supply voltage is low, as the higher the power supply voltage.

[0218] This suppresses the occurrence of differences in the rotational speed of the bit movement motor 50 due to fluctuations in the power supply voltage. Therefore, it suppresses the occurrence of excessive impact when the screw 200 is pressed against the object to be fastened, and also suppresses variations in the speed at which the screw 200 is pressed against the object to be fastened.

[0219] In step SF6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SF9, it stops driving the bit rotation motor 40, and in step SF10, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SF11, it reverses the bit movement motor 50.

[0220] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0221] In step SF12, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SF13.

[0222] Figure 27 is a flowchart showing other variations of the operation of the fastening tool of this embodiment. Next, other variations of the fastening operation of the fastening tool of this embodiment will be described with reference to each figure. In this variation, the load on the bit moving motor 50, etc., is detected to suppress driving when there are no screws.

[0223] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0224] In step SG1 of Figure 27, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 is turned on in step SG2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SG3, 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.

[0225] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52, and the second moving member 32c moves forward, along with the moving member 32 connected to the wire 54 and the holding member 30 connected to the moving member 32 by the first moving member 32a.

[0226] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0227] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0228] As a result, the driver bit 2 held by the retaining member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the object to be fastened. The control unit 100 moves the driver bit 2 forward with the second drive unit 5 in conjunction with the operation of rotating the driver bit 2 with the first drive unit 4 to screw the screw into the object to be fastened, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0229] In step SG6, 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 driver bit 2 has reached the set operation 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 SG7, it detects the load on either the bit rotation motor 40 or the bit movement motor 50, or both. When a predetermined load is detected as the screw 200 is pressed against the object to be fastened, the bit movement motor 50 continues to rotate in the forward direction until its rotational speed reaches the set value selected by the setting unit 110.

[0230] In step SG6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SG8, ​​it stops driving the bit rotation motor 40, and in step SG9, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SG10, it reverses the bit movement motor 50.

[0231] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0232] In step SG11, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SG12.

[0233] When the bit rotation motor 40 and bit movement motor 50 rotate in the forward direction while the screw 200 is not in the ejection port 81a, the screw 200 is not pressed against the object to be fastened, and therefore the load on the bit rotation motor 40 and bit movement motor 50 does not increase. For this reason, even if the driver bit 2 attached to the holding member 30 moves forward by a predetermined amount of movement based on the length of the smallest screw 200 to be loaded, if no predetermined load is detected, it can be determined that the screw 200 is not present.

[0234] Therefore, in step SG13, the control unit 100 determines whether the bit movement motor 50 has rotated, based on a predetermined amount of movement relative to the length of the smallest screw 200 to be loaded, a predetermined amount of free-spinning detection for the driver bit 2 attached to the holding member 30 to move forward. If the control unit 100 determines that a predetermined load has not been detected by either the bit rotation motor 40 or the bit movement motor 50, or both, and that the bit movement motor 50 has rotated by the predetermined amount of free-spinning detection, it determines that there is no screw 200 and notifies an error in step SG14. In addition, the driving of the bit rotation motor 40 and the bit movement motor 50 is stopped in the processing of steps SG8 to SG12 described above.

[0235] The control unit 100 may detect the load on either the bit rotation motor 40 or the bit movement motor 50, or both, by measuring the change in current flowing through the motor, excluding the current change that occurs when the motor starts up. Alternatively, it may detect the load by measuring the change in voltage flowing through the motor, excluding the voltage change that occurs when the motor starts up. In addition, the rotation of the bit holding unit 3 and the axial movement of the bit holding unit 3 may be performed by a single motor, and the control unit 100 may detect the load on the single motor and suppress driving when there is no screw.

[0236] Next, another modification of the fastening operation of the fastening tool of this embodiment will be described. In this modification, in the feedback control that synchronizes the movement speed of the driver bit by the bit moving motor 50 with the movement speed of the screw by the rotation of the bit rotating 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 fastening operation. In this modification, the lead length of the screw 200 means the distance the screw 200 advances in one rotation.

[0237] Figure 28 is a flowchart showing another modified example of the operation of the fastening tool of this embodiment. Note that the graph showing the relationship between the rotational speeds of the bit rotation motor and the bit movement motor under feedback (FB) control is the same as in Figure 24A, and the graph showing the relationship between the screw movement speed due to the rotation of the bit rotation motor under feedback (FB) control and the driver bit movement speed due to the bit movement motor is the same as in Figure 24B. Therefore, the explanation of each graph will be given by referring to Figures 24A and 24B.

[0238] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0239] In step SH1 of Figure 28, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact arm 82 presses the contact switch unit 84, the contact switch unit 84 turns on in step SH2, the trigger 9 is operated, and the trigger switch unit 90 turns on in step SH3. In step SH4, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4, and in step SH5, it drives the bit movement motor 50 of the second drive unit 5.

[0240] When the bit moving motor 50 is driven to rotate in the forward direction which is one direction, the pulley 52 rotates in the forward direction, so that the wire 54 is wound around the pulley 52, and the second moving member 32c, the moving member 32 connected to the wire 54, and the holding member 30 connected between the moving member 32 and the first moving member 32a move forward.

[0241] As a result, the driver bit 2 held by the holding member 30 moves forward in the forward direction indicated by the arrow A1, engages with the screw 200 supplied to the ejection port 81a of the nose portion 8, and moves the screw 200 forward to press it against the fastening object.

[0242] Also, when the bit rotation motor 40 is driven to rotate in the forward direction which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0243] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the fastening object. The control unit 100 causes the driver bit 2 to move forward by the second drive unit 5 in conjunction with the operation of rotating the driver bit 2 by the first drive unit 4 to screw the screw into the fastening object, so that the driver bit 2 follows the screw being screwed into the fastening object.

[0244] The control unit 100 determines whether the rotational speed of the bit moving motor 50 has reached the set value selected by the setting unit 110 and the tip of the driver bit 2 has reached the set operation end position P2 in step SH6. When the control unit 100 determines that the rotational speed of the bit moving motor 50 has not reached the set value selected by the setting unit 110, in step SH7, it detects the load applied to at least one of the bit rotation motor 40 and the bit moving motor 50, and when detecting a predetermined load, in step SH8, it acquires the rotational speed of the bit rotation motor 40 and the rotational speed of the bit moving motor 50.

[0245] In step SH9, the control unit 100 calculates the target rotational speed of the bit movement motor 50 using the information on the lead length of the screw 200 obtained during the previous screw tightening operation. Specifically, as the screw 200 is fastened to the fastening object by the rotation of the bit rotation motor 40, the moving speed when the screw 200 moves forward, the holding member 30 and the moving member 32 that move forward by the rotation of the bit movement motor 50, and the moving speed of the driver bit 2 attached to the holding member 30 are substantially the same as shown in FIG. 24B. Based on the lead length of the screw 200, the rotational speed of the bit rotation motor 40, the gear ratio of the speed reducer, etc., the target rotational speed of the bit movement motor 50 is obtained. For example, the control unit 100 calculates the target rotational speed of the bit movement motor 50 based on the following formula (1). Target rotational speed of bit movement motor 50 = (Gear ratio of speed reducer of bit movement motor 50 / Gear ratio of speed reducer of bit rotation motor 40 × Circumference of pulley 52 / Lead length of screw 200) × Rotational speed of bit rotation motor 40 ··· (1)

[0246] In step SH10, the control unit 100 performs feedback control based on the rotational speed of the bit rotation motor 40, the gear ratio of the speed reducer, etc. In this example, the control unit 100 controls the bit movement motor 50 so that the calculated target rotational speed is achieved. For example, the control is performed by adjusting the rotational speed by increasing or decreasing the PWM output to the bit movement motor 50.

[0247] In step SH11, after detecting the load applied to the bit rotation motor 40 or the bit movement motor 50, the control unit 100 measures the rotational speed of the bit rotation motor 40. Further, in step SH12, after detecting the load applied to the bit rotation motor 40 or the bit movement motor 50, the control unit 100 measures the rotational speed of the bit movement motor 50. The rotational speed of the bit rotation motor 40 and the rotational speed of the bit movement motor 50 measured in step SH11 and step SH12 are stored in a memory (not shown) and used in step SH18 for calculating the lead length of the screw 200 during the next screw tightening operation. After the measurement in step SH12 is completed, the process returns to step SH6.

[0248] In step SH6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SH13, it stops driving the bit rotation motor 40, and in step SH14, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SH15, it reverses the bit movement motor 50.

[0249] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0250] In step SH16, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SH17.

[0251] Once the series of screw tightening operations are completed, the control unit 100 calculates the lead length of the screw 200 in step SH18 using the following procedure. Note that the calculation of the lead length of the screw 200 may also be performed in parallel with the reverse control of the bit movement motor 50, etc., before or after the processing in step SH13 or step S14, in addition to the calculation after the screw tightening operations are completed.

[0252] First, calculate the rotational speed of screw 200 based on the following formula (2). Rotational speed of screw 200 = Rotational speed of bit rotation motor 40 from the start of screw tightening (after load detection) until screw 200 is fully tightened (step SH11) / Gear ratio of the reduction gear of bit rotation motor 40 ... (2) In the above equation (2), the rotational speed of the bit rotation motor 40 was acquired for the entire period from load detection until the screw 200 was fully tightened. However, this is not limited to this, and the rotational speed of the bit rotation motor 40 may be acquired for only a portion of the entire period.

[0253] Next, the length of screw 200 is calculated based on the following formula (3). The length of screw 200 (the amount of movement of driver bit 2 from the start of tightening until screw 200 is fully tightened) = the number of rotations of bit movement motor 50 from the start of tightening until the screw is fully tightened (step SH12) / the gear ratio of the reduction gear of bit movement motor 50 × the circumference of pulley 52 ... (3) In the above equation (3), the rotational speed of the bit moving motor 50 was acquired for the entire period from load detection until the screw 200 was fully tightened. However, this is not limited to this, and the rotational speed of the bit moving motor 50 may be acquired for only a portion of the entire period.

[0254] Next, the lead length of screw 200 is calculated based on the following formula (4). Lead length of screw 200 = Length of screw 200 (Equation (3)) / Number of rotations of screw 200 (Equation (2)) ... (4)

[0255] 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 to be 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 in one screw tightening cycle is determined (calculated), and this determined lead length is used to calculate the penetration speed (movement speed) of the driver bit 2 into the object to be fastened per rotation and the rotational speed of the bit movement motor 50 during the next screw tightening operation.

[0256] 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 to be fastened by the drive of the bit rotation motor 40 can be accurately calculated. As a result, the movement speed of the driver bit 2 can be precisely matched to the penetration speed of the screw 200 during screw tightening after load detection, thereby reducing the force required to hold down the fastening tool 1 during screw tightening, thereby reducing the workload, and improving the quality of the screwing by suppressing the lifting of the fastening tool 1.

[0257] Next, another modification of the fastening operation of the fastening tool of this embodiment will be described. In this modification, in the feedback control that makes the moving speed of the driver bit by the bit moving motor 50 follow the moving speed of the screw by the rotation of the bit rotating motor 40, the target rotation speed of the bit moving motor 50 is calculated using the screw lead length set in the lead length setting unit 120.

[0258] Figure 29 is a block diagram showing another variation of the operation of the fastening tool of this embodiment. As shown in Figure 29, 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, respectively.

[0259] The lead length setting unit 120 accepts the setting of the lead length according 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 be provided on the tool body 10. In this case, the lead length setting unit 120 may be configured as an operating unit such as a button or a rotary dial, and the user may manually input the lead length of the screw 200 by operating these buttons, or the user may be able to select a specific lead length from a set of multiple lead lengths. Alternatively, the functionality of the lead length setting unit 120 may be provided to an information processing terminal such as a personal computer, tablet, or smartphone, 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.

[0260] The control unit 100 changes the lead length used when calculating the rotational speed of the bit moving motor 50 (described later) to the lead length of the screw 200 set in the lead length setting unit 120. This allows switching from the lead length information of the screw 200 used in the previous screw tightening operation to the lead length information that matches the type of screw 200 used in the current screw tightening operation.

[0261] Figure 30 is a flowchart showing another modified example of the operation of the fastening tool of this embodiment. Note that the graph showing the relationship between the rotational speeds of the bit rotation motor and the bit movement motor under feedback (FB) control is the same as in Figure 24A, and the graph showing the relationship between the screw movement speed due to the rotation of the bit rotation motor under feedback (FB) control and the driver bit movement speed due to the bit movement motor is the same as in Figure 24B. Therefore, the explanation of each graph will be given by referring to Figures 24A and 24B.

[0262] In its standby state, as shown in Figure 1A, the fastening tool 1A has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0263] In step SI1 of Figure 30, the control unit 100 sets the rotational speed of the bit moving motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected by the setting unit 110.

[0264] In step SI2, the lead length setting unit 120 accepts a lead length setting according to the type of screw 200 based on the operator's operation. After accepting the lead length setting, the process proceeds to step SI3. If no lead length setting for the screw 200 is accepted, the lead length setting used during the previous screw tightening operation is maintained.

[0265] In step SI3, the control unit 100 sets the lead length of the screw 200 received by the lead length setting unit 120 as the lead length used when calculating the rotational speed of the bit moving motor 50 described later. Also, the control unit 100 stores the information on the lead length of the screw 200 received by the lead length setting unit 120 in a memory (not shown). After setting the new lead length, the process proceeds to step SI4.

[0266] When the contact member 81 is pressed against the fastening object, the contact switch unit 84 is pushed by the contact arm 82, the contact switch unit 84 is turned on in step SI4, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SI5, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SI6 and drives the bit moving motor 50 of the second drive unit 5 in step SI7.

[0267] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, the wire 54 is wound around the pulley 52, and the moving member 32c of the second moving member 32, the moving member 32 connected to the wire 54, and the holding member 30 connected to the moving member 32 and the first moving member 32a move forward. As a result, the driver bit 2 held by the holding member 30 moves forward in the direction indicated by the arrow A1, engages with the screw 200 supplied to the ejection port 81a of the nose portion 8, and moves the screw 200 forward to press it against the fastening object.

[0268] When the bit rotation motor 40 is driven and rotates in the forward direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31. As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the fastening object. The control unit 100 causes the driver bit 2 to move forward by the second drive unit 5 in conjunction with the operation of rotating the driver bit 2 by the first drive unit 4 to screw it into the fastening object, so that the driver bit 2 follows the screw being screwed into the fastening object.

[0269] In step SI8, 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 driver bit 2 has reached the set operation 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, it proceeds to step SI9.

[0270] In step SI9, the control unit 100 detects whether a load is applied to at least one of the bit rotation motor 40 and the bit movement motor 50. If a predetermined load is detected, in step SI10, it obtains the rotational speed of the bit rotation motor 40 and the rotational speed of the bit movement motor 50, respectively.

[0271] In step SI11, when the screw 200 is fastened to the object by the rotation of the bit rotation motor 40, the control unit 100 determines the target rotation speeds of the bit rotation motor 40 and the bit movement motor 50 based on the lead length of the screw 200 set in the lead length setting unit 120, the rotation speed of the bit rotation motor 40 and the rotation speed of the bit movement motor 50, the gear ratio of the reduction gear, etc., so that the speed at which the screw 200 moves forward and the speed at which the driver bit 2 moves forward by the rotation of the bit movement motor 50 are approximately the same (see Figure 24B). For example, the control unit 100 calculates the target rotation speed of the bit movement motor 50 based on the following equation (5). Target rotational speed of bit moving motor 50 = (Gear ratio of bit moving motor 50's reducer / Gear ratio of bit rotating motor 40's reducer × Circumference of pulley 52 / Lead length of screw 200) × Rotational speed of bit rotating motor 40 ... (5)

[0272] In step SI12, the control unit 100 controls the bit moving motor 50 using feedback control based on the rotational speed of the bit rotating motor 40, the rotational speed of the bit moving motor 50, the gear ratio of the reduction gear, etc. In this example, it controls the bit moving motor 50 so that it reaches the calculated target rotational speed. For example, this is done by increasing or decreasing the PWM output to the bit moving motor 50 to adjust the rotational speed.

[0273] In step SI8, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SI13, it stops driving the bit rotation motor 40, and in step SI14, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SI15, it reverses the bit movement motor 50.

[0274] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0275] In step SI16, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SI17.

[0276] The means for switching the lead length setting of the screw 200 does not have to be the lead length setting unit 120. Specifically, a communication unit may be provided in the fastening tool 1A, etc., and a non-powered communication unit may be provided on the connecting band (reel) side to which the multiple screws 200 loaded into the screw storage unit 6 are attached, and short-range wireless communication may be performed between the communication unit and the non-powered communication unit. The non-wireless communication unit stores, for example, an IC chip that associates the type of screw 200 with the lead length of the screw 200. When the connecting band is stored in the screw storage unit 6, the communication unit obtains the lead length of the screw 200 to be fastened by wireless communication with the non-wireless communication unit, and the control unit 100 switches the lead length setting to the newly obtained lead length. Examples of short-range wireless communication methods include non-contact methods using electromagnetic fields or radio waves, Bluetooth®, etc.

[0277] Furthermore, the means for switching the lead length setting of the screw 200 may be an identification means that mechanically identifies the dimensions of the connecting band loaded in the screw storage section 6. In this case, the lead length differs depending on the type of screw 200, and consequently, the width, groove position, number, etc. of the connecting band also differ. Therefore, the type of connecting band is mechanically identified from these differences in the connecting band, and the lead length of the screw 200 is obtained.

[0278] According to this modified example, even if the type of screw 200 used is different, the lead length setting can be switched in the lead length setting unit 120. Therefore, it is possible to switch to the lead length of the screw 200 actually used in the screw tightening work, so compared to, for example, calculating the rotation speed of the bit moving motor 50 using the previous lead length, it is possible to accurately calculate the penetration depth and penetration speed of the screw 200 into the object to be fastened by driving the bit rotating motor 40. As a result, the movement speed of the driver bit 2 can be made to follow the penetration speed of the screw 200 with high precision during screw tightening after load detection, reducing the force required to hold down the fastening tool 1A during screw tightening, thereby reducing the workload, and improving the quality of the screwing by suppressing the lifting of the fastening tool 1A.

[0279] Next, another modification of the fastening operation of the fastening tool of this embodiment will be described. In this modification, in the feedback control that synchronizes the movement speed of the driver bit by the bit moving motor 50 with the movement speed of the screw by the rotation of the bit rotating motor 40, the current value of the bit moving motor 50 is controlled to stay within a specified range during the screw tightening operation.

[0280] Figure 31 is a flowchart showing other variations of the operation of the fastening tool of this embodiment, Figure 32 is a graph showing the relationship between the load and the control of the bit movement motor, and Figure 33 is a diagram showing the engagement state between the driver bit and the screw recess when tightening a screw.

[0281] In its standby state, as shown in Figure 1A, the fastening tool 1 has the tip of the driver bit 2 positioned at a standby position P1 behind the injection passage 80, allowing it to supply screws 200 to the injection passage 80.

[0282] In step SJ1 of Figure 31, the control unit 100 sets the rotation speed of the bit movement motor 50 that defines the amount of forward movement of the driver bit 2, based on the setting value selected in the setting unit 110. When the contact member 81 is pressed against the object to be fastened, and the contact switch unit 84 is pressed by the contact arm 82, the contact switch unit 84 is turned on in step SJ2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SJ3, 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.

[0283] When the bit moving motor 50 is driven and rotates in the forward direction, which is one direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound onto the pulley 52, and the second moving member 32c moves forward, along with the moving member 32 connected to the wire 54 and the holding member 30 connected to the moving member 32 by the first moving member 32a.

[0284] As a result, the driver bit 2 held by the retaining member 30 moves forward in the direction indicated by arrow A1, engages with the screw 200 supplied to the nozzle 81a of the nose portion 8, moves the screw 200 forward, and presses it against the object to be fastened.

[0285] Furthermore, when the bit rotation motor 40 is driven and rotates in the positive direction, which is one direction, the holding member 30 rotates together with the rotation guide member 31.

[0286] As a result, the driver bit 2 held by the retaining member 30 rotates the screw 200 in the forward direction (clockwise) and screws it into the object to be fastened. The control unit 100 moves the driver bit 2 forward with the second drive unit 5 in conjunction with the operation of rotating the driver bit 2 with the first drive unit 4 to screw the screw into the object to be fastened, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0287] 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 driver bit 2 has reached the set operation 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, it detects the load on the bit movement motor 50, and if a predetermined load is detected, in step SJ8, it obtains the rotational speed of the bit movement motor 50.

[0288] 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 to stay within a preset range according to the rotation speed of the bit movement motor 50 that it has acquired. As a result, during the screw tightening operation, even if the screw 200 moves forward quickly or slowly depending on the state of the object to be fastened, for example, the output torque remains constant. This makes it possible to perform the screw tightening operation without requiring excessive force from the operator to press the fastening tool 1 against the object to be fastened, while keeping the driver bit 2 in follow with the moving screw 200.

[0289] Furthermore, as shown in Figure 32, after detecting the load of screw tightening, the target value of the current of the bit movement motor 50 is set to gradually increase in accordance with the increase in load during screw tightening and the decrease in the rotational speed of the bit rotation motor 40 during screw tightening. This is for the following reasons: During screw tightening, it is necessary to maintain engagement between the driver bit 2 and the screw recess. However, as the screw tightening progresses and the load during screw tightening increases, as shown in Figure 33, the forces acting along the wall surface 200a of the engagement portion of the screw recess in directions B1 and B2 that cause the engagement between the driver bit 2 and the screw 200 to disengage increases. Therefore, it is necessary to increase the force pressing the driver bit 2 against the screw 200 to prevent the engagement between the driver bit 2 and the screw 200 from disengaging, and it is desirable to increase the current value of the bit movement motor 50 as the screw tightening progresses.

[0290] Therefore, as shown in Figure 32, the control unit 100 sets the current value immediately after the load of the screw tightening operation is detected as a first specified value T1, and the current value at the end of the screw tightening operation as a second specified value T2. For example, the first specified value T1 is set to be within the range of 10A to 30A, and the second specified value T2 is set to be within the range of more than 30A and 60A or less. In this case, during the current control implementation period, the control unit 100 sets the current value of the bit moving motor 50 so that it gradually increases from the set first specified value T1 to the second specified value T2. Furthermore, if the rotation speed of the bit moving motor 50 acquired in step SJ8 is less than a preset threshold, it is preferable to set the current values ​​of the first specified value T1 and the second specified value T2 higher within the set range compared to when the rotation speed of the bit moving motor 50 is greater than the threshold. Note that each of the first specified value T1 and the second specified value T2 may be changed as appropriate by the operator from the operation unit or the like. Once you have set all the default values, proceed to step SJ10.

[0291] In step SJ10, the control unit 100 controls the current value of the bit movement motor 50 so that it falls within the range between the set first default value T1 and the second default value T2. For example, the control unit 100 controls the current value of the bit movement motor 50 within the range between the first default value T1 and the second default value T2 by PWM control by switching the switching elements of the drive circuit on or off, and adjusts the rotation speed of the bit movement motor 50.

[0292] In step SJ6, 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, and that the tip of the driver bit 2 has reached the set operation end position P2. In step SJ11, it stops driving the bit rotation motor 40, and in step SJ12, it stops the rotation of the bit movement motor 50 in the forward direction. Then, in step SJ13, it reverses the bit movement motor 50.

[0293] When the bit moving motor 50 rotates in the opposite direction, the pulley 52 rotates in the opposite direction, pulling the wire 54 out of the pulley 52, and the moving member 32, which is pushed by the biasing member 33, and the holding member 30, which is connected to the moving member 32 by the first moving member 32a, move backward.

[0294] In step SJ14, the control unit 100 reverses the bit movement motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52. ​​Once the holding member 30 and the moving member 32 have moved backward to the position where the tip of the driver bit 2 returns to the standby position P1, the control unit 100 stops the reverse rotation of the bit movement motor 50 in step SJ15.

[0295] According to this modified example, the current value of the bit movement motor 50 is controlled to fall within the range between a first specified value T1 and a second specified value T2, so that the force (load) applied by the driver bit 2 to the screw 200 can be controlled to be constant. As a result, even if the screw 200 advances quickly or slowly depending on the working conditions, the engagement between the driver bit 2 and the recess of the screw 200 can be maintained, and the movement speed of the driver bit 2 can be made to follow the insertion speed of the screw 200. As a result, excessive pressure on the fastening tool 1 during screw tightening is avoided, reducing the workload, while suppressing the lifting of the fastening tool 1 and improving the quality of screw driving. [Explanation of Symbols]

[0296] 1,1A... Fastening tool, 10... Tool body, 10a... Case, 10b... Front frame, 10c... Rear frame, 10d... Connecting member, 10e... Screw, 10f... Nose body, 11... Handle, 12... Battery, 13... Battery mounting part, 2... Driver bit, 3... Bit holder, 30... Holding member, 30a... Opening, 30b... Connecting part Material, 31... Rotating guide member, 31a... Groove, 32... Moving member, 32a... First moving member, 32b... Bearing, 32c... Second moving member, 33... Biasing member, 34a... Bearing, 4... First drive unit, 40... Bit rotation motor (motor, first motor), 40a... Shaft, 41... Reducer, 41a... Shaft, 42... Bearing Ring (bearing), 5...Second drive unit, 50...Bit moving motor (motor, second motor), 50a...Shaft, 51...Reduction gear, 51a...Shaft, 52...Pulley (transmission member), 53...Bearing, 54...Wire (transmission member), 6...Screw housing, 7...Screw feed unit, 70...Screw feed motor, 71...Pinion gear, 72...Rack gear, 73...Section Joint section, 8... Nose section, 80... Injection passage, 81... Contact member, 81a... Injection port, 82... Contact arm, 83... Adjustment section, 84... Contact switch section, 9... Trigger, 90... Trigger switch section, 100... Control section, 110... Setting section, 120... Lead length setting section, T1... First specified value (specified value), T2... Second specified value (specified value)

Claims

1. A bit holder that detachably holds the driver bit, A first motor rotates the bit holder in the circumferential direction of the driver bit, A second motor moves the bit holding portion along the axial direction, The system includes a control unit that controls the axial movement speed of the bit holding unit using the rotational speed of the second motor, The control unit, when at least one of the first motor and the second motor detects a predetermined load due to contact between a screw and a target member by a change in current or voltage, executes control to determine the rotational speed of the second motor based on the rotational speed of the first motor so that the bit holding part moves in synchronization with the movement of the screw fastened to the target member by the rotation of the first motor.

2. A bit holder that detachably holds the driver bit, A first motor rotates the bit holder in the circumferential direction of the driver bit, A second motor moves the bit holding portion along the axial direction, The system includes a control unit that controls the axial movement speed of the bit holding unit using the rotational speed of the second motor, The control unit, when at least one of the first motor and the second motor detects a predetermined load due to contact between a screw and a target member by a change in current or voltage, executes control to determine the rotational speed of the first motor based on the rotational speed of the second motor so as to synchronize the movement of the screw fastened to the target member by the rotation of the first motor with the movement of the bit holding part that moves by the rotation of the second motor.

3. The fastening tool according to claim 1 or 2, wherein the control unit calculates the lead length of the screw using the rotational speed of the first motor or the amount of movement of the bit holder, measured after detecting the load applied to the first motor or the second motor, and calculates the movement speed of the bit holder based on the calculated lead length.

4. It is equipped with a lead length setting unit that allows the lead length to be set, The fastening tool according to claim 1 or 2, wherein the control unit calculates the movement speed of the bit holder based on the lead length of the screw set by the lead length setting unit.

5. The fastening tool according to claim 1 or 2, wherein the control unit reduces the movement speed of the bit holding part due to the rotation of the second motor as the power supply voltage increases, compared to the case where the power supply voltage is low, based on fluctuations in the power supply voltage.

6. The fastening tool according to claim 1 or 2, wherein the control unit, after detecting the load, controls the load of the second motor so that it falls within a specified range.

Images