Fastening tool

Abstract

To provide a fastening tool capable of controlling a movement end position of a driver bit by an operation of moving the driver bit in a direction of fastening a screw.SOLUTION: The fastening tool 1 includes a bit holding part 3 that detachably holds the driver bit 2 and is rotatable in a circumferential direction of the driver bit 2 and movable in an axial direction of the driver bit 2, a bit rotation motor 40 that rotates the bit holding part 3, a bit movement motor 50 that moves the bit holding part 3 along the axial direction, a contact member 81 that contacts an object to be fastened to which a screw engaged with the driver bit 2 is to be fastened, and a control unit 100 that controls a timing of stopping driving of the bit rotation motor 40 and the bit movement motor 50 based on ON or OFF of a contact switch part that is switched between ON and OFF according to a movement amount of the contact member 81 in the axial direction when the contact member 81 contacts the object to be fastened.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a fastening tool in which a driver bit is engaged with a screw, the screw is pressed against an object to be fastened by the driver bit, and the driver bit is rotated to screw in the screw. [Background technology]

[0002] A portable tool known as a driving machine is known that uses the air pressure of compressed air supplied from an air compressor or the combustion pressure of gas to drive connecting fasteners loaded in a magazine one after another from the tip of a driver guide.

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

[0004] Also, a screw driver has been proposed in which a spring is compressed by the driving force of a motor that rotates the screw, and the screw is driven in by the biasing force of the spring (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5262461 [Patent Document 2] Patent No. 6197547 Summary of the Invention [Problem to be solved by the invention]

[0006] In both screw drivers that use air pressure and screw drivers that use spring force to drive screws, it is difficult to control the end position of the driver bit when it moves in the direction of tightening the screw, and it is difficult to control the screw head to be flush with the object to be fastened.

[0007] The present invention has been made to solve such problems, and aims to provide a fastening tool that makes it possible to control the end position of the driver bit movement by moving the driver bit in the direction of tightening the screw. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a fastening tool comprising: a bit holding portion that detachably holds a driver bit and is rotatable in the circumferential direction of the driver bit and movable in the axial direction; a motor that rotates the bit holding portion and moves the bit holding portion along the axial direction; a contact member that contacts the fastening object to which the screw engaged with the driver bit is fastened; a contact switch portion that is switched on and off depending on the amount of axial movement of the contact member when it contacts the fastening object; and a control portion that controls the timing to stop driving the motor based on the on or off state of the contact switch portion.

[0009] In the present invention, the rotation or movement of the driver bit is prevented from ending before the driver bit reaches the movement end position.

[0010] The present invention also provides a fastening tool comprising: a bit holding portion that detachably holds a driver bit and is rotatable in the circumferential direction of the driver bit and movable in the axial direction; a motor that rotates the bit holding portion; a fluctuation detection portion that detects factors that cause fluctuations in the rotational speed of the motor; and a control portion that, when the fluctuation detection portion detects factors that cause fluctuations in the rotational speed of the motor, performs control to suppress fluctuations in the rotational speed of the motor.

[0011] In the present invention, after the motor stops rotating, the driver bit is prevented from rotating due to inertia and tightening the screw, so fluctuations in the motor's rotational speed are suppressed so that the driver bit can stop at the end of its movement position.

[0012] Furthermore, the present invention is a fastening tool comprising: a bit holding portion that is rotatable in the circumferential direction of a driver bit and movable in the axial direction; a motor that rotates the bit holding portion and moves the bit holding portion along the axial direction; an operable trigger for driving the motor; a contact member that comes into contact with an object to be fastened and is movable in the axial direction; a contact arm that is movable in the axial direction in conjunction with the contact member; a position detection portion that detects the position of the contact arm that has moved in response to the contact member coming into contact with the object to be fastened; and a control portion that determines whether the contact arm is on or off based on the position of the contact arm detected by the position detection portion, drives the motor when both the conditions of the trigger being on and the contact arm being on are met, and controls the timing for stopping the drive of the motor based on the on or off state of the contact arm. [Effects of the Invention]

[0013] In the present invention, the movement end position of the driver bit can be controlled by the operation of moving the driver bit in the direction of tightening the screw. [Brief explanation of the drawings]

[0014] [Figure 1A] FIG. 2 is a side cross-sectional view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 1B] FIG. 2 is a top cross-sectional view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 1C] FIG. 2 is a front cross-sectional view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 2A] FIG. 2 is an exploded perspective view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 2B] 1 is a perspective view showing an example of a fastening tool according to an embodiment of the present invention; [Figure 3A] 1 is a perspective view showing an example of a configuration of a main part of a fastening tool according to an embodiment of the present invention; [Figure 3B] 1 is a perspective view showing an example of a configuration of a main part of a fastening tool according to an embodiment of the present invention; [Figure 4A] 1 is a cross-sectional perspective view showing an example of a configuration of a main part of a fastening tool according to an embodiment of the present invention; [Figure 4B] 1 is a cross-sectional perspective view showing an example of a configuration of a main part of a fastening tool according to an embodiment of the present invention; [Figure 4C] 1 is a cross-sectional perspective view showing an example of a configuration of a main part of a fastening tool according to an embodiment of the present invention; [Figure 5] 1 is a top cross-sectional view showing an example of a configuration of a main part of a fastening tool according to an embodiment of the present invention. [Figure 6A] FIG. 2 is a top cross-sectional view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 6B] FIG. 2 is a top cross-sectional view showing an example of the internal structure of the fastening tool of the present embodiment. [Figure 7A] FIG. 10 is a cross-sectional view showing an example of a detachable holding mechanism. [Figure 7B] FIG. 10 is a cross-sectional view showing an example of a detachable holding mechanism. [Figure 8A] FIG. 10 is a perspective view showing an example of a detachable holding mechanism. [Figure 8B] FIG. 10 is a perspective view showing an example of a detachable holding mechanism. [Figure 9] FIG. 2 is a perspective view showing an example of a screw feed portion and a nose portion of the present embodiment. [Figure 10A] FIG. 2 is a perspective view showing an example of the fastening tool of the present embodiment, as viewed from the rear. [Figure 10B] FIG. 2 is a perspective view showing an example of the fastening tool of the present embodiment, as viewed from the rear. [Figure 10C] FIG. 2 is a perspective view showing an example of the fastening tool of the present embodiment, as viewed from the rear. [Figure 11] FIG. 2 is a perspective view illustrating an example of a setting unit. [Figure 12] 1 is a block diagram showing an example of a fastening tool according to an embodiment of the present invention; [Figure 13A] 10A and 10B are side cross-sectional views showing an example of the operation of the fastening tool of the present embodiment. [Figure 13B] 10A and 10B are cross-sectional top views showing an example of the operation of the fastening tool of the present embodiment. [Figure 14] 4 is a flowchart showing an example of an operation of the fastening tool according to the present embodiment. [Figure 15A] FIG. 4 is a cross-sectional view showing a fastened state of the screw. [Figure 15B] FIG. 4 is a cross-sectional view showing a fastened state of the screw. [Figure 15C] FIG. 4 is a cross-sectional view showing a fastened state of the screw. [Figure 16A] 10A and 10B are explanatory views showing an example of an operation for setting standby positions of a holding member and a moving member in a first initialization operation. [Figure 16B] 10A and 10B are explanatory views showing an example of an operation for setting standby positions of a holding member and a moving member in a first initialization operation. [Figure 16C] 10A and 10B are explanatory views showing an example of an operation for setting standby positions of a holding member and a moving member in a first initialization operation. [Figure 16D] 10A and 10B are explanatory views showing an example of an operation for setting standby positions of a holding member and a moving member in a first initialization operation. [Figure 17A] 10A and 10B are explanatory views showing an example of an operation of moving the holding member and the moving member to the standby position in the second initialization operation. [Figure 17B] 10A and 10B are explanatory views showing an example of an operation of moving the holding member and the moving member to the standby position in the second initialization operation. [Figure 17C] 10A and 10B are explanatory views showing an example of an operation of moving the holding member and the moving member to the standby position in the second initialization operation. [Figure 18] 10 is a flowchart showing an example of an operation for selecting a first initialization operation and a second initialization operation. [Figure 19] 10 is a flowchart showing a modified example of the operation of the fastening tool of the present embodiment. [Figure 20] 10 is a graph showing the relationship between the output of the contact switch unit and the control of the bit rotating motor and the bit moving motor. [Figure 21] 10 is a flowchart showing another modified example of the operation of the fastening tool of the present embodiment. [Figure 22A] 10 is a graph showing the relationship between the load and the control of the bit rotation motor. [Figure 22B]10 is a graph showing the relationship between the load and the control of the bit rotation motor. [Figure 23] 10 is a flowchart showing another modified example of the operation of the fastening tool of the present embodiment. [Figure 24A] 10 is a graph showing the relationship between the rotation speed of a bit rotating motor and a bit moving motor under feedback control. [Figure 24B] 10 is a graph showing the relationship between the moving speed of a screw caused by the rotation of a bit rotating motor under feedback control and the moving speed of a driver bit caused by a bit moving motor. [Figure 25] 10 is a flowchart showing another modified example of the operation of the fastening tool of the present embodiment. [Figure 26A] 10 is a graph showing the relationship between the load and the control of the bit moving motor. [Figure 26B] 10 is a graph showing the relationship between the load and the control of the bit moving motor. [Figure 27] 10 is a flowchart showing another modified example of the operation of the fastening tool of the present embodiment. [Figure 28] FIG. 10 is an external side view showing another modified example of the fastening tool of the present embodiment. [Figure 29] FIG. 10 is a block diagram showing another modified example of the fastening tool of the present embodiment. [Figure 30] 10 is a flowchart showing another modified example of the operation of the fastening tool of the present embodiment. [Figure 31] 10 is a flowchart showing another modified example of the operation of the fastening tool of the present embodiment. [Figure 32] 10 is a graph showing the relationship between the position state of the contact member and the control of the bit rotating motor and the bit moving motor. [Figure 33] FIG. 10 is a block diagram showing another modified example of the fastening tool of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the fastening tool of the present invention will be described with reference to the drawings.

[0016] <Configuration example of fastening tool according to this embodiment> Fig. 1A is a side cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, Fig. 1B is a top cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, Fig. 1C is a front cross-sectional view showing an example of the internal structure of the fastening tool of this embodiment, Fig. 2A is an exploded perspective view showing an example of the internal structure of the fastening tool of this embodiment, and Fig. 2B is an external perspective view showing an example of the fastening tool of this embodiment.

[0017] The fastening tool 1 of this embodiment includes a bit holding unit 3 that holds a driver bit 2 rotatably and axially movable, 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.

[0018] The fastening tool 1 also includes a screw storage section 6 in which the screw 200 is stored, a screw feed section 7 that feeds the screw stored in the screw storage section 6, and a nose section 8 that is pressed against an object to be fastened with the screw 200 and from which the screw is ejected.

[0019] Furthermore, the fastening tool 1 includes a tool body 10 and a handle 11. The fastening tool 1 also includes, at the end of the handle 11, a battery attachment portion 13 to which a battery 12 is detachably attached.

[0020] In the fastening tool 1, the tool body 10 extends in one direction along the axial direction of the driver bit 2 indicated by arrows A1 and A2, and the handle 11 extends in another direction intersecting the extension direction of the tool body 10. In the fastening tool 1, 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 defined as the front-rear direction. In addition, in the fastening tool 1, the direction in which the handle 11 extends is defined as the up-down direction. Furthermore, in the fastening tool 1, the direction perpendicular to the extension direction of the tool body 10 and the extension direction of the handle 11 is defined as the left-right direction.

[0021] The first drive unit 4 is provided on one side of the tool body 10, i.e., the rear side, across the handle 11. The second drive unit 5 is provided on the other side of the tool body 10, i.e., the front side, across the handle 11.

[0022] The screw storage section 6 stores a plurality of screws 200 connected by a connecting band and wound in a spiral shape.

[0023] 3A and 3B are perspective views showing an example of the configuration of the main parts of the fastening tool of this embodiment, Figures 4A to 4C are cross-sectional perspective views showing an example of the configuration of the main parts of the fastening tool of this embodiment, and Figure 5 is a top cross-sectional view showing an example of the configuration of the main parts 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.

[0024] The bit holding portion 3 is an example of a tool holder, and includes a holding member 30 that detachably holds a driver bit 2, which is an example of a tool, a rotating guide member 31 that supports the holding member 30 so that it can move in the forward and backward directions 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 forward and backward directions along the rotating guide member 31, and a biasing member 33 that biases the moving member 32 in the backward direction indicated by arrow A2.

[0025] The holding member 30 is configured as, for example, a cylindrical member whose outer diameter is slightly smaller than the inner diameter of the rotation guide member 31 and which can be placed inside the rotation guide member 31. The holding member 30 has an opening 30a at its front end along the axial direction of the driver bit 2, the opening 30a having a shape that matches the cross-sectional shape of the driver bit 2. The holding member 30 is provided with a detachable holding mechanism 30c in the opening 30a that detachably holds the driver bit 2. The opening 30a of the holding member 30 is exposed to the inside of the rotation guide member 31, and the driver bit 2 is detachably inserted into the opening 30a.

[0026] The rotation guide member 31 extends in the extension direction of the tool body 10, i.e., in the front-to-rear direction indicated by arrows A1 and A2 along the axial direction of the driver bit 2. The rotation guide member 31 has a cylindrical shape with the holding member 30 fitted inside, and its front end is rotatably supported via a bearing 34a, which is an example of a bearing, on a metal front frame 10b provided on the front side of a resin case 10a that constitutes the exterior of the tool body 10. The rear end of the rotation guide member 31 is connected to the first drive unit 4.

[0027] The rotation guide member 31 has grooves 31a formed at two radially opposing sides thereof, the grooves 31a extending in the front-to-rear direction indicated by arrows A1 and A2 along the axial direction of the driver bit 2. The rotation guide member 31 penetrates the holding member 30 in the radial direction, and connecting members 30b protruding from both sides of the holding member 30 enter the grooves 31a, thereby connecting the rotation guide member 31 to the holding member 30 via the connecting members 30b.

[0028] The holding member 30 has a hole that penetrates in a direction perpendicular to the rotation 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 formed of a cylindrical member with an oval cross section.

[0029] The longitudinal direction of the oval shape of the connecting member 30b is oriented along the extension direction of the groove 31a which is parallel to the axial direction of the driver bit 2 as indicated by arrows A1 and A2, and the lateral direction of the oval shape is oriented perpendicular to the extension direction of the groove 31a as indicated by arrows B1 and B2, i.e., along the rotation direction of the rotation guide member 31. The width of the oval shape of the connecting member 30b in the lateral direction, i.e., the width along the rotation direction of the rotation guide member 31, is configured to be slightly smaller than the width of the groove 31a along the same direction.

[0030] As a result, the connecting member 30b inserted in the groove 31a is supported in the groove 31a so as to be movable along the axial direction of the rotation guide member 31. Furthermore, the movement of the connecting member 30b in the rotational direction relative to the rotation guide member 31 is restricted between one side surface and the other side surface of the groove 31a that are aligned along the extension direction of the groove 31a. Therefore, as the rotation guide member 31 rotates, the connecting member 30b is pressed against one side surface or the other side surface of the groove 31a depending on the rotational direction of the rotation guide member 31, and receives a force from the rotation guide member 31 in the circumferential direction, which is the rotational direction.

[0031] Therefore, when the rotation guide member 31 rotates, the connecting member 30b is pressed into the groove portion 31a of the rotation guide member 31, causing the holding member 30 to rotate together with the rotation guide member 31. Furthermore, the connecting member 30b is guided by the groove portion 31a of the rotation guide member 31, causing the holding member 30 to move in the front-to-rear direction along the axial direction of the driver bit 2.

[0032] The moving member 32 is an example of a transmission member, and includes a first moving member 32a that rotates together with the holding member 30 and moves the holding member 30 in the forward and backward directions along the rotation guide member 31, a second moving member 32c that is supported by the first moving member 32a via a bearing 32b and pushes the first moving member 32a via the bearing 32b, and a buffer member 32d that is attached to the rear side of the second moving member 32c.

[0033] The first moving member 32a has an inner diameter slightly larger than the outer diameter of the rotation guide member 31 and is configured as, for example, a cylindrical member that is placed on the outside of the rotation guide member 31. The first moving member 32a is connected to the holding member 30 via a connecting member 30b that protrudes from a groove portion 31a of the rotation guide member 31, and is supported so as to be movable along the axial direction of the rotation guide member 31.

[0034] Bearing 32b is an example of a bearing, and is inserted between the outer periphery of first moving member 32a and the inner periphery of second moving member 32c. First moving member 32a constitutes a bearing inner ring holding member that holds the inner ring of bearing 32b, and second moving member 32c constitutes a bearing outer ring holding member that holds the outer ring of bearing 32b. The inner ring of bearing 32b is supported on the outer periphery of first moving member 32a so as to be immovable in both the rotational and axial directions, and the outer ring is supported on the inner periphery of second moving member 32c so as to be immovable in both the rotational and axial directions.

[0035] As a result, the second moving member 32c is connected to the first moving member 32a via the bearing 32b in a state where movement in the front-to-rear direction along the axial direction is restricted. Also, the second moving member 32c rotatably supports the first moving member 32a via the bearing 32b.

[0036] Therefore, as the second moving member 32c moves back and forth along the axial direction, the first moving member 32a is pushed by the second moving member 32c via the bearing 32b, and moves back and forth along the axial direction together with the second moving member 32c. In addition, the first moving member 32a is rotatable relative to the second moving member 32c, which is non-rotatable relative to the rotation guide member 31.

[0037] The biasing member 33, in this example, is formed by a coil spring and is placed outside the rotation 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 abuts against a spring seat 32f that is arranged so as 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 forward as indicated by arrow A1, and applies a force to the moving member 32 that pushes the moving member 32 backward as indicated by arrow A2.

[0038] The first drive unit 4 includes a bit rotation motor 40 driven by electricity supplied from the battery 12, and a reducer 41. The bit rotation motor 40 is an example of a motor or first motor, and a shaft 40a of the bit rotation motor 40 is connected to the reducer 41, and a shaft 41a of the reducer 41 is connected to the rotation guide member 31. In the first drive unit 4, the reducer 41 is configured using a planetary gear, and the bit rotation motor 40 is arranged coaxially with the rotation guide member 31, the holding member 30, and the driver bit 2 held by the holding member 30.

[0039] The first drive unit 4 has a bit rotation motor 40 and a reducer 41 attached to a metal rear frame 10c provided on the rear side of the case 10a of the tool body 10, and a shaft 41a of the reducer 41 is supported by the rear frame 10c via a bearing 42. The rear end of the rotation guide member 31 is connected to the shaft 41a of the reducer 41, and the shaft 41a is supported by the rear frame 10c via the bearing 42, so that the rotation guide member 31 is rotatably supported via the bearing 42, which is an example of a bearing.

[0040] The bit holding unit 3 and the first drive unit 4 are assembled together by connecting the front frame 10b and the rear frame 10c with a connecting member 10d extending in the front-to-rear direction, and the front frame 10b is fixed to the case 10a of the tool body 10 with screws 10e.

[0041] Furthermore, the front end of the rotation guide member 31 of the bit holding part 3 is supported via a bearing 34a on a front frame 10b fixed to the front side of the case 10a of the tool body 10, and the rear end of the rotation guide member 31 is supported via a shaft 41a of the reducer 41 and a bearing 42 on a rear frame 10c fixed to the rear side of the case 10a. Thus, the rotation guide member 31 of the bit holding part 3 is rotatably supported on the tool body 10.

[0042] As a result, the first driving unit 4 rotates the rotary guide member 31 using the bit rotation motor 40. When the rotary guide member 31 rotates, the holding member 30 that holds the driver bit 2 rotates together with the rotary guide member 31 as the connecting member 30b is pressed into the groove portion 31a of the rotary guide member 31.

[0043] A guide member 32g is provided on the second moving member 32c of the bit holding unit 3. A pair of guide walls 10g is provided on the connecting member 10d at a distance slightly larger than the diameter of the guide member 32g, and by inserting the guide member 32g between the pair of guide walls 10g, the pair of guide walls 10g face the circumferential surface of the guide member 32g.

[0044] As a result, the second moving 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.

[0045] 6A and 6B are top cross-sectional views showing an example of the internal structure of the fastening tool of the present embodiment, and show details of the second drive unit 5. Next, the second drive unit 5 will be described with reference to each drawing.

[0046] The second drive unit 5 includes a bit moving motor 50 driven by electricity supplied from the battery 12, and a reducer 51. The bit moving motor 50 is an example of a motor or a second motor, and a shaft 50a of the bit moving motor 50 is connected to the reducer 51, and a shaft 51a of the reducer 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 arranged along the extension direction of the handle 11.

[0047] In the second driving unit 5, one end of a linear wire 54, which is an example of a transmission member, is connected to the pulley 52, and the wire 54 is wound around the pulley 52 as the pulley 52 rotates. The other end of the wire 54 is connected to a wire connecting portion 32h provided on the second moving member 32c of the moving member 32.

[0048] As a result, the second drive unit 5 rotates the pulley 52 using the bit moving motor 50 to wind up the wire 54, thereby moving the second moving member 32c forward as indicated by the arrow A1. As 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 together with the second moving member 32c along the axial direction of the bit holding unit 3. As the first moving member 32a moves forward, the holding member 30 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 the arrow A1.

[0049] The second drive unit 5 is disposed offset to one side with respect to the approximate center in the left-right direction of the fastening tool 1 so that the tangent direction of the portion of the pulley 52 around which the wire 54 is wound is along the extension direction of the rotation guide member 31. That is, the center of the pulley 52, in this example, the shaft 50a of the bit moving motor 50, is offset to one side with respect to the rotation guide member 31, and the portion 52a of the pulley 52 around which the wire 54 is wound overlaps with the rotation guide member 31 when viewed in the axial direction of the pulley 52.

[0050] In addition, the wire 54 between the pulley 52 and the second moving member 32c is arranged so that it is parallel to the axial direction of the rotating guide member 31 in the radial direction of the pulley 52, as shown in Figures 6A and 6B, and 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, as shown in Figure 1A.

[0051] Furthermore, when the wire 54 is wound around the pulley 52 in an overlapping manner, the distance from the center of the pulley 52 to the wire 54 changes depending on the number of turns, and therefore the amount of movement of the driver bit 2 changes when the pulley 52 makes one rotation. Also, the angle formed between the direction in which the wire 54 extends between the pulley 52 and the second moving member 32c and the direction in which the driver bit 2 moves along the axial direction of the rotation guide member 31 changes.

[0052] Therefore, the diameter and the like of the pulley 52 are set so that the rotation amount α of the pulley 52 required to move the driver bit 2 by a predetermined amount is less than 360°.

[0053] 6B, when the pulley 52 winds the wire 54 to move the driver bit 2 a predetermined distance, the wire 54 is not wound around the pulley 52 in an overlapping manner, which prevents the amount of movement of the driver bit 2 from becoming inaccurate. Also, 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 moving direction of the driver bit 2 along the axial direction of the rotation guide member 31 are prevented.

[0054] Therefore, the relationship between the rotation speed of the bit moving motor 50 and the movement amount of the holding member 30 is one to one throughout the entire movable range of the holding member 30, and by controlling the rotation speed of the bit moving motor 50, it is possible to control the movement amount of the holding member 30 along the axial direction of the rotation guide member 31. In other words, by controlling the rotation speed of the bit moving motor 50, it is possible to control the movement amount of the driver bit 2 attached to the holding member 30.

[0055] Furthermore, regardless of the amount of winding of the wire 54, the tension applied to the wire 54 is always parallel to the movement direction of the driver bit 2 along the axial direction of the rotation guide member 31, thereby suppressing a decrease in the movement of the driver bit 2 and the transmission efficiency of the force for pushing the screw 200 via the driver bit 2.

[0056] This allows the wire 54 between the pulley 52 and the second moving member 32c to extend in a straight line along the moving direction of the moving member 32, suppressing the increase in load when the wire 54 is wound around the pulley 52 and the increase in load when the wire 54 is pulled out from the pulley 52.

[0057] Note that the wire 54 is flexible enough to be wound around the pulley 52, and therefore cannot push the second moving member 32c to move the moving member 32 rearward. Therefore, a biasing member 33 is provided that is compressed when the moving member 32 moves forward in the direction indicated by arrow A1, and applies a force to the moving member 32 that pushes the moving member 32 rearward in the direction indicated by arrow A2. This allows the pulley 52 to wind up the wire 54, moving the driver bit 2 forward, and allowing the driver bit 2 to move backward after moving forward.

[0058] In addition, the holding member 30 that holds the driver bit 2 is supported so as to be movable in the forward and backward directions relative to the rotating guide member 31 by engagement between a connecting member 30b provided on the holding member 30 and a groove portion 31a provided on the rotating guide member 31, and rotates together with the rotating guide member 31.

[0059] Therefore, the bit rotation motor 40 is arranged coaxially with the rotation guide member 31, the holding member 30, and the driver bit 2 held by the holding member 30, and a configuration can be realized in which the driver bit 2 is rotated and moved in the forward and backward directions without moving the bit rotation motor 40 in the forward and backward directions.

[0060] In a configuration in which the bit rotation motor 40 is arranged coaxially with the driver bit 2, a feed screw may be used to convert the rotation of the bit rotation motor 40 into movement of the driver bit 2 in the forward and backward directions.

[0061] However, in a configuration using a feed screw, the amount of advancement of the driver bit 2 per motor rotation cannot be made large, so even if the rotation speed of the motor is increased, it is difficult to increase the movement speed of the driver bit 2.

[0062] In the fastening tool 1, the movement speed of the driver bit 2 needs to be increased in order to shorten the time it takes for the driver bit 2 to press the screw 200 against the object to be fastened, but with a configuration that uses a feed screw, it is difficult to shorten the time it takes for the driver bit 2 to press the screw 200 against the object to be fastened.

[0063] In contrast, in a configuration in which 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 rotation guide member 31, and the second drive unit 5 rotates the pulley 52 to wind up the wire 54 and move the holding member 30 forward, the movement speed of the driver bit 2 can be increased according to the rotation speed of the bit movement motor 50. Therefore, the time until the driver bit 2 presses the screw 200 against the object to be fastened can be shortened.

[0064] 7A and 7B are cross-sectional views showing an example of the detachable holding mechanism, and FIGS. 8A and 8B are perspective views showing an example of the detachable holding mechanism, showing details of the detachable holding mechanism 30c. Next, the detachable holding mechanism 30c will be described with reference to these figures.

[0065] The detachable holding mechanism 30c includes a ball 30d exposed in the opening 30a and a spring 30e that biases the ball 30d in the direction of exposure in the opening 30a. The spring 30e is an annular leaf spring and is fitted around the outer periphery of the holding member 30.

[0066] When the insertion portion 20 of the driver bit 2 is inserted into the opening 30a of the holding member 30, the ball 30d of the detachable holding mechanism 30c is pushed by the insertion portion 20, and the ball 30d deforms the annular spring 30e in a direction that increases the diameter of the spring 30e, while retreating toward the outer periphery of the holding member 30.

[0067] When the insertion portion 20 of the driver bit 2 is inserted into the opening 30a of the holding member 30 until the groove 20a formed on the outer periphery 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 accidentally coming off the holding member 30.

[0068] Furthermore, when a force greater than a predetermined value is applied in the direction of removing the driver bit 2 from the holding member 30, the ball 30d retracts while deforming the annular spring 30e in the direction of increasing the diameter of the spring 30e, thereby enabling the driver bit 2 to be removed from the holding member 30.

[0069] When the insertion portion 20 of the driver bit 2 is inserted into or removed from the opening 30a of the holding member 30, the ball 30d retreats toward the outer periphery of the holding member 30. For this reason, a space into which the ball 30d retreats is required on the outer periphery of the holding member 30. However, the holding member 30 is inserted inside the cylindrical rotation guide member 31, and no space into which the ball 30d retreats can be secured between the outer periphery of the holding member 30 and the inner periphery of the rotation guide member 31.

[0070] Furthermore, if a difference in diameter between the holding member 30 and the rotation guide member 31 is set to ensure a space for the balls 30d to retreat between the outer periphery of the holding member 30 and the inner periphery of the rotation guide member 31, the outer diameter of the holding member 30 cannot be reduced because the radial dimension of the driver bit 2 is fixed, and therefore the outer diameter of the rotation guide member 31 must be increased, which results in an increase in the size of the device.

[0071] In contrast, groove 31a that guides connecting member 30b is provided in rotation guide member 31. Groove 31a penetrates rotation guide member 31 from the inner periphery to the outer periphery, and extends in the axial direction of rotation guide member 31.

[0072] Therefore, the detachable holding mechanism 30c is provided so that the ball 30d is aligned with the position of the groove 31a of the rotation guide member 31. That is, in the holding member 30, the connecting member 30b and the ball 30d of the detachable holding mechanism 30c are provided coaxially along the axial direction of the rotation guide member 31. As a result, in the detachable holding mechanism 30c, the ball 30d is exposed to the groove 31a of the rotation guide member 31 both when the rotation guide member 31 and the holding member 30 rotate and when the holding member 30 moves axially relative to the rotation guide member 31.

[0073] Therefore, when the insertion portion 20 of the driver bit 2 is inserted into or removed from the opening 30 a of the holding member 30 , the balls 30 d retreating toward the outer periphery of the holding member 30 enter the grooves 31 a of the rotation guide member 31 .

[0074] Therefore, a space for retracting the ball 30d of the detachable holding mechanism 30c can be secured with a configuration in which the holding member 30 is inserted inside the cylindrical rotation guide member 31. Also, by using the groove 31a into which the connecting member 30b is inserted as the space for retracting the ball 30d, the area of ​​the opening provided in the rotation guide member 31 is reduced, and strength can be secured.

[0075] Furthermore, there is no need to increase the diameter difference between the holding member 30 and the rotating guide member 31 to secure space for the ball 30d to retreat between the outer periphery of the holding member 30 and the inner periphery of the rotating guide member 31, which prevents the device from becoming too large.

[0076] 9 is a perspective view showing an example of the screw feed portion and nose portion of this embodiment, and shows the details of the screw feed portion 7 and nose portion 8. Next, the screw feed portion 7 and nose portion 8 will be described with reference to each drawing.

[0077] The screw feed unit 7 includes a screw feed motor 70, a pinion gear 71 attached to the shaft of the screw feed motor 70 via a reducer, a rack gear 72 that meshes with the pinion gear 71, and an engagement unit 73 that is connected to the rack gear 72 and engages with the connecting screw fed from the screw storage unit 6.

[0078] The screw feed unit 7 supports a rack gear 72 so that it can move up and down along the feed direction of the connecting screw. When the screw feed motor 70 rotates forward and backward, the screw feed unit 7 moves an engagement portion 73 that engages with the connecting screw up and down, thereby feeding the connecting screw.

[0079] The nose portion 8 is supplied with the screws 200 by the screw feed portion 7 and is equipped with an injection passage 80 through which the driver bit 2 passes, a contact member 81 having an injection port 81a communicating with the injection passage 80 and coming into contact with an object to be fastened, a contact arm 82 that moves in the front-to-rear direction in conjunction with the contact member 81, and an adjustment portion 83 that regulates the amount of movement of the contact arm 82. The nose portion 8 also includes a cover member 88 that opens and closes the path through which the screws 200 pass from the screw storage portion 6 to the injection passage 80.

[0080] The fastening tool 1 has a nose portion 8 that is formed by assembling the parts that make up the injection passage 80, the contact member 81, and the contact arm 82, and is fixed to a front frame 10b and a nose main body portion 10f that make up the tool body 10. The fastening tool 1 also has a contact switch portion 84 that is activated when pressed by the contact arm 82.

[0081] Nose portion 8 supports contact member 81 so that it can move in the front-to-rear direction indicated by arrows A1 and A2, and contact arm 82 moves in the front-to-rear direction in conjunction with contact member 81. In nose portion 8, contact member 81 is urged forward by a urging member (not shown), and contact member 81, which is pressed against an object to be fastened and moves rearward, is then urged forward by the urging member.

[0082] In the nose portion 8, the contact member 81 is pressed against the object to be fastened, causing the contact arm 82 to move rearward, and the amount of movement of the contact arm 82 until the contact switch portion 84 is activated is adjusted by the adjustment portion 83. The contact switch portion 84 is switched between activated and inactivated when pressed by the contact arm 82, and in this example, the state in which the contact switch portion 84 is not pressed by the contact arm 82 and is inactivated is referred to as the off state of the contact switch portion 84, and the state in which the contact switch portion 84 is pressed by the contact arm 82 and is activated is referred to as the on state of the contact switch portion 84.

[0083] Next, with reference to the respective drawings, a description will be given of the configuration related to the control and operation of the fastening tool 1. The fastening tool 1 is equipped with a trigger 9 that is operated, and a trigger switch unit 90 that is actuated by operating the trigger 9. The trigger 9 is provided on the front side of the handle 11, and is configured to be operable by the fingers of the hand that grips the handle 11. The trigger switch unit 90 is actuated when pressed by the trigger 9.

[0084] The trigger switch unit 90 is switched between activated and inactive when pressed by the trigger 9. In this example, the trigger switch unit 90 is in an inactive state when the trigger 9 is not operated and the trigger 9 does not press the trigger switch unit 90, and is in an off state when the trigger 9 is operated and pressed by the trigger 9, causing the trigger switch unit 90 to be activated.

[0085] The fastening tool 1 is equipped with a control unit 100 that controls the first drive unit 4, the second drive unit 5, and the screw feed unit 7 based on the outputs of a trigger switch unit 90 that is activated by operating a trigger 9 and a contact switch unit 84 that is activated by being pressed by a contact member 81.

[0086] The control unit 100 is configured from a board on which various electronic components are mounted, and is provided in a board housing portion 111 provided on the rear side of the screw housing portion 6 between the screw housing portion 6 and the handle 11.

[0087] In power tools that are used by holding the handle in one hand, a storage compartment for storing consumables such as screws is provided in front of the handle. To be able to grip the handle with one's hand, there must be enough space between the handle and the storage compartment for one's fingers to fit in.

[0088] Therefore, the fastening tool 1 is provided with a board storage section 111 on the rear side of the screw storage section 6, utilizing the space between the screw storage section 6 and the handle 11.

[0089] For power tools that are used by holding the handle in one hand, a configuration has been proposed in which a battery is attached to the bottom of the handle and a circuit board is provided between the handle and the battery, but this configuration increases the vertical dimension of the power tool along the extension direction of the handle.

[0090] In contrast, by providing the board 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 prevented from increasing. Furthermore, since the screw storage section 6 stores spirally wound connecting screws, the surface of the screw storage section 6 facing the handle 11 is substantially circular. This ensures the capacity of the board storage section 111 while preventing the fastening tool 1 from becoming larger.

[0091] 10A to 10C are perspective views showing an example of the fastening tool according to the present embodiment as viewed from behind, and Fig. 11 is a perspective view showing an example of a setting section, illustrating details of the setting section 110. Next, the setting section 110 will be described with reference to the respective drawings.

[0092] The fastening tool 1 is equipped with a second drive unit 5 that moves the driver bit 2 back and forth along the axial direction, and 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 driven and rotated by the bit moving motor 50, and a holding member 30 connected to the moving member 32, move forward along the axial direction of the driver bit 2 along the rotating guide member 31.

[0093] This makes it possible to control the amount of movement (amount of 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 advances following the screw 200 as the screw 200 is fastened, can be controlled by the rotation speed of the bit movement motor 50, and the stop position of the driver bit 2 along the axial direction can be controlled.

[0094] Therefore, the fastening tool 1 is provided with a setting unit 110 that sets the advance amount of the driver bit 2. The setting unit 110 is an example of a setting means, and is configured to allow any setting value to be selected from a plurality of setting values, or to allow any setting value to be selected in a stepless manner.

[0095] In this example, the setting unit 110 is configured such that a setting value is selected by an operation unit 110a that is configured with buttons. Alternatively, the operation unit 110a may be configured such that a setting value is selected by a rotary dial. Alternatively, the setting unit 110 may be configured to display the selected setting value by a method of indicating the current value with a label or marking, or by a method of indicating the current value on a display unit 110b such as an LED, so that the operator can easily grasp the current setting value.

[0096] The setting sections 110 are provided on both the left and right sides of the surface facing the handle 11 in the board storage section 111 provided on the rear side of the screw storage section 6.

[0097] This makes it possible to visually recognize the setting portion 110 from both the left and right sides of the handle 11 when the fastening tool 1 is viewed from the rear.

[0098] When the handle 11 is held by hand, the surface 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 surface facing the handle 11 in the board storage section 111 provided on the back side of the screw storage section 6, the display section 110b provided on the setting section 110 is easily visible. This reduces the possibility that the operator will miss the display. The information displayed on the display section 110b includes the set screw depth determined by the advancement amount of the driver bit 2, the power ON / OFF status, the selected operating mode from various selectable operating modes, the presence or absence of screws, the remaining amount of screws, the presence or absence of any abnormalities, etc.

[0099] Furthermore, when the handle 11 is held by hand, the operation unit 110a, such as buttons, provided on the setting unit 110 is also easily visible. Therefore, while holding the handle 11 with one hand, the operation unit 110a can be operated with the other hand while visually checking the operation unit 110a, ensuring reliable operation.

[0100] Furthermore, the board storage section 111 stores a board that constitutes the control section 100. By mounting switches and the like that constitute the operation section 110a and lamps and the like that constitute the display section 110b on the surface of this board that faces the handle 11, a board for the setting section 110 that is separate from the control section 100 can be omitted.

[0101] 12 is a block diagram showing an example of the fastening tool of this embodiment. As described above, the fastening tool 1 includes the second drive unit 5 that moves the driver bit 2 back and forth 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 is driven to rotate by the bit moving motor 50. The holding member 30 and the moving member 32 move forward along the axial direction of the driver bit 2 along the rotation guide member 31.

[0102] As a result, the control unit 100 can control the movement amount (advancement amount) 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 to fasten the screw 200, the amount of advancement 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, and the stop position of the driver bit 2 along the axial direction can be controlled.

[0103] In addition, the control unit 100 sets the number of rotations of the bit moving motor 50, which determines the amount of advancement of the driver bit 2, in the setting unit 110. Furthermore, the control unit 100 controls whether or not to drive the bit moving motor 50 of the second drive unit 5 and the bit rotation motor 40 of the first drive unit 4, based on a combination of on / off of the contact switch unit 84 and on / off of the trigger switch unit 90.

[0104] <Example of operation of the fastening tool according to this embodiment> FIG. 13A is a side cross-sectional view showing an example of the operation of the fastening tool of this embodiment, FIG. 13B is a top cross-sectional view showing an example of the operation of the fastening tool of this embodiment, and FIG. 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.

[0105] In the fastening tool 1, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0106] 14, the control unit 100 sets the rotation speed of the bit moving motor 50, which determines the advance amount of the driver bit 2, based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object to be fastened, the contact switch unit 84 is pressed by the contact arm 82, 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 moving motor 50 of the second drive unit 5 in step SA5.

[0107] When the bit moving motor 50 is driven to rotate in one direction, which is the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52. ​​As the wire 54 is wound around the pulley 52, the second moving member 32c connected to the wire 54 moves forward in the axial direction, guided by the rotation guide member 31. When 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 moves forward in the axial direction together with the second moving member 32c while compressing the biasing member 33.

[0108] When the first moving member 32a moves forward, the holding member 30 connected to the first moving 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 portion 31a of the rotating guide member 31.

[0109] As a result, the driver bit 2 held by the holding member 30 moves forward as indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, and moves the screw 200 forward, pressing it against the object to be fastened.

[0110] Furthermore, when the bit rotation motor 40 is driven to rotate in one direction, that is, the forward direction, the rotation guide member 31 rotates in the forward direction. When the rotation guide member 31 rotates in the forward direction, the connecting member 30b connected to the holding member 30 is pressed against the groove portion 31a of the rotation guide member 31, causing the holding member 30 to rotate together with the rotation guide member 31.

[0111] 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 rotating the driver bit 2 with the first drive unit 4 to 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., so that the driver bit 2 follows the screw being screwed into the object to be fastened.

[0112] When the control unit 100 determines in step SA6 that the rotation speed of the bit moving 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, it stops driving the bit rotation motor 40 in step SA7, stops the rotation of the bit moving motor 50 in the forward direction in step SA8, and then reverses the rotation of the bit moving motor 50 in step SA9.

[0113] When the bit moving motor 50 rotates in the other direction, that is, the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52. ​​When 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 rearward.

[0114] The second moving member 32c is pushed rearward by the biasing member 33, and moves rearward along the axial direction while being guided by the rotation guide member 31. When the second moving member 32c moves rearward, the first moving member 32a is pulled by the second moving member 32c via the bearing 32b, and moves rearward along the axial direction together with the second moving member 32c.

[0115] When the first moving member 32a moves rearward, the holding member 30 connected to the first moving member 32a by the connecting member 30b moves rearward along the axial direction of the driver bit 2, with the connecting member 30b being guided by the groove portion 31a of the rotating guide member 31.

[0116] In step SA10, the control unit 100 reverses the rotation of the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SA11.

[0117] Furthermore, by providing the moving member 32 with a buffer member 32d made of rubber or the like on the rear side of the second moving member 32c, the second moving member 32c is prevented from directly hitting the rear frame 10c when it moves rearward, thereby suppressing 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 portion 73. When the engaging portion 73 has lowered to a position where it will engage with the next screw 200, the control unit 100 reverses the rotation of the screw feed motor 70 to raise the engaging portion 73 and supply the next screw 200 to the injection passage 80.

[0118] Figures 15A to 15C are cross-sectional views showing the fastening state of a screw, with Figure 15A showing a so-called flush state in which the head 201 of the screw 200 is neither floating above nor embedded in the surface of the object 202 to be fastened, Figure 15B showing a state in which the head 201 of the screw 200 is floating above the object 202 to be fastened, and Figure 15C showing a state in which the head 201 of the screw 200 is embedded in the object 202 to be fastened.

[0119] In the fastening tool 1, when the tip of the driver bit 2 reaches the operation end position P2, if the screw 200 is a flat head screw, it is preferable that the advancement amount of the driver bit 2 is set so that the surface of the head 201 of the screw 200 is flush with the surface of the object 202 to be fastened, as shown in Fig. 15A. Note that the screw 200 is not limited to a flat head screw, and if it is a pan head screw, bind, truss screw, or the like, it is preferable that the advancement amount of the driver bit 2 is set so that the bearing surface of the head 201 of the screw 200 comes into contact with the surface of the object 202 to prevent the head 201 of the screw 200 from floating above the object 202.

[0120] When the tip of the driver bit 2 reaches the operation end position P2, if the head 201 of the screw 200 is floating above the object 202 to be fastened as shown in Fig. 15B, the movement amount (advance amount) of the driver bit 2 is set by the setting unit 110, and the advance amount of the driver bit 2 is increased by increasing the number of rotations (amount of rotation) of the bit moving motor 50, thereby moving the operation end position P2 forward. On the other hand, if the head 201 of the screw 200 is embedded in the object 202 to be fastened as shown in Fig. 15C, the movement amount (advance amount) of the driver bit 2 is set by the setting unit 110, and the advance amount of the driver bit 2 is decreased by decreasing the number of rotations of the bit moving motor 50, thereby moving the operation end position P2 backward.

[0121] As described above, the movement amount (advancement amount) of the driver bit 2 is determined by the number of rotations of the bit moving motor 50. Then, starting from the standby position P1, which is the initial position of the driver bit 2, the bit moving motor 50 is rotated by the number of rotations set by the setting unit 110, and then the operation end position P2 is controlled by stopping or reversing the rotation of the bit moving motor 50. Thus, the drive depth can be adjusted.

[0122] In this way, 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 so that the tip position of the driver bit 2 held by the holding member 30 can move forward a predetermined amount based on the rotation speed of the bit moving motor 50, with a predetermined standby position P1 as the reference. The operation of setting the standby positions of the holding member 30 and the moving member 32 is referred to as a first initialization operation.

[0123] Then, before starting the driving and fastening operations, 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 the standby position as the reference. The holding member 30 and the moving member 32 are then advanced a predetermined amount (advancement amount) from the set standby position to perform the fastening operation. The operation of moving the holding member 30 and the moving member 32 to the standby position set in the first initialization operation is referred to as the second initialization operation.

[0124] 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 as a reference the maximum position within the range in which the holding member 30 and the moving member 32 can move back and forth. When a sensor is used, the standby position is set to the position detected by the sensor or a position moved a specified distance from the detected position.

[0125] When the maximum position in the range of forward and backward movement is used, the holding member 30 and the moving member 32 are set to a position where they are moved a specified distance from the front end position or the rear end position as the standby position.

[0126] 16A to 16D are explanatory diagrams showing an example of the operation of setting the standby positions of the holding member and the moving member in the first initialization operation, and next, we will explain the operation of setting the standby positions of the holding member 30 and the moving member 32. Note that Figures 16A to 16D show an example of the operation of setting the standby positions using the maximum positions in the range in which the holding member 30 and the moving member 32 can move forward and backward.

[0127] 16A, the control unit 100 rotates the bit moving motor 50 in one direction, that is, the forward direction, from a state in which 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 around the pulley 52, and the moving member 32 and the holding member 30 connected to the moving member 32 move forward along the axial direction of the driver bit 2, along the rotation guide member 31.

[0128] As shown in Figure 16B, when the bit moving motor 50 rotates in the forward direction until the holding member 30 and the moving member 32 move to one of the end positions, the front end position PF, the control unit 100 stops the forward rotation of the bit moving motor 50 and moves the holding member 30 and the moving member 32 to the front end position PF.

[0129] Next, the control unit 100 rotates the bit moving motor 50 in the other direction, that is, the reverse direction. When the bit moving motor 50 rotates in the reverse direction, the wire 54 is pulled out from the pulley 52, and the moving member 32 is pushed rearward by the biasing member 33, and the moving member 32 and the holding member 30 connected to the moving member 32 move rearward along the axial direction of the driver bit 2 along the rotation guide member 31.

[0130] As shown in Figure 16C, when the bit moving motor 50 reverses until the holding member 30 and the moving member 32 move to the rear end position PE, which is the other end position, the control unit 100 stops the reverse rotation of the bit moving motor 50 and moves the holding member 30 and the moving member 32 to the rear end position PE by the force of the biasing member 33.

[0131] The control unit 100 acquires the movement amount 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 movement amount from the front end position PF to the rear end position PE is calculated from the rotation speed of the bit moving motor 50.

[0132] The control unit 100 presets the movement amount of the holding member 30 and the moving member 32 from the standby position 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 preset target movement amount L2 as the standby position movement amount L3 and stores it. The standby position movement amount L3 is the movement amount of the holding member 30 and the moving member 32 from the rear end position PE.

[0133] 16D, the control unit 100 rotates the bit moving motor 50 in the forward direction, moving the holding member 30 and the moving member 32 forward from the rear end position PE. After rotating the bit moving motor 50 in the forward direction by a number of rotations equivalent to the standby position movement amount L3, the control unit 100 stops the forward rotation of the bit moving 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.

[0134] 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 that does not affect the durability of the tool, for example, when the second moving member 32c hits the buffer member 32d.

[0135] Figures 17A to 17C are explanatory diagrams showing an example of the operation of moving the holding member and the moving member to a standby position in the second initialization operation. Next, the operation of moving the holding member 30 and the moving member 32 to a preset standby position will be described.

[0136] 17A, the control unit 100 rotates the bit moving motor 50 in the other direction, that is, the reverse direction, from a state in which the holding member 30 and the moving member 32 are in any position. When the bit moving motor 50 rotates in the reverse direction, the wire 54 is pulled out from the pulley 52, and the moving member 32 is pushed rearward by the biasing member 33, and the moving member 32 and the holding member 30 connected to the moving member 32 move rearward along the axial direction of the driver bit 2 along the rotation guide member 31.

[0137] As shown in Figure 17B, when the bit moving motor 50 rotates in the reverse 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 rotation of the bit moving motor 50 and moves the holding member 30 and the moving member 32 to the rear end position PE by the force of the biasing member 33.

[0138] 17C, the control unit 100 rotates the bit moving motor 50 in the forward direction, moving the holding member 30 and the moving member 32 forward from the rear end position PE. After rotating the bit moving motor 50 in the forward direction by a number of rotations equivalent to the standby position movement amount L3, the control unit 100 stops the forward rotation of the bit moving 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.

[0139] In the first initialization operation described in Figures 16A to 16D, the operation of setting the standby positions of the holding member 30 and the moving member 32 is performed, for example, at a factory when the product is shipped, without being operated by the user, and the standby position movement amount L3 is stored in advance.

[0140] On the other hand, in the second initialization operation described in Figures 17A to 17C, the operation of moving the holding member 30 and the moving member 32 to the standby position based on the standby position movement amount L3 is preferably performed every time the fastening tool 1 is turned on in order to ensure stable fastening operations.

[0141] Therefore, a first initialization operation and a second initialization operation, which are initialization operations relating to the standby positions of the holding member 30 and the moving member 32, are configured to be selectable.

[0142] FIG. 18 is a flowchart showing an example of an operation for selecting the first initialization operation and the second initialization operation.

[0143] When the power is turned on in step SB1 of Fig. 18, the control unit 100 selects an initialization operation to be performed in step SB2. If the control unit 100 selects the execution of the first initialization operation, it executes the first initialization operation described above in Figs. 16A to 16D in step SB3 to set the standby positions of the holding member 30 and the moving member 32. If the control unit 100 selects the execution of the second initialization operation, it executes the second initialization operation described above in Figs. 17A to 17C in step SB4 to move the holding member 30 and the moving member 32 to the standby positions based on the standby position movement amount L3. After executing the second initialization operation, the control unit 100 executes a normal fastening operation in step SB5 in accordance with the flowchart of Fig. 14 and the like.

[0144] 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, and the movement amount from the rear end position PE, which is determined so that the movement amount from the front end position PF is equal to a predetermined target movement amount L2, is set as the standby position movement amount L3 and recorded in memory on a circuit board (not shown) that constitutes the control unit 100. This makes it possible to eliminate various variations in the machine, such as dimensional differences within tolerance ranges, and to set the standby positions of the holding member 30 and the moving member 32 to, for example, a fixed position from the front end position PF.

[0145] 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 standby position movement amount L3, thereby minimizing the movement amount of the holding member 30 and the moving member 32. Furthermore, in the second initialization operation, the tip of the driver bit 2 is positioned at the standby position P1 behind the injection passage 80, and the second initialization operation can be performed in a state in which the screw 200 is supplied to the injection passage 80.

[0146] As described above, the movement amount (advancement amount) of the driver bit 2 is determined by the number of rotations of the bit moving motor 50, starting from the standby position of the holding member 30 and the moving member 32, i.e., the standby position P1 of the 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 by the setting unit 110 will vary.

[0147] In contrast, by performing the second initialization operation each time the power is turned on, the screw tightening depth can be accurately adjusted by rotating the bit moving motor 50 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.

[0148] Fig. 19 is a flowchart showing a modified example of the operation of the fastening tool of this embodiment, and Fig. 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, another example of the fastening operation of the fastening tool of this embodiment will be described with reference to these figures. In this modified example, the presence or absence of lift of the fastening tool 1 relative to the object to be fastened is detected from the output of the contact switch unit 84, and the bit rotation motor 40 and bit movement motor 50 are controlled.

[0149] In the fastening tool 1, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0150] 19, the control unit 100 sets the number of rotations of the bit moving motor 50, which determines the amount of advancement of the driver bit 2, based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object to be fastened, the contact switch unit 84 is pressed by the contact arm 82, the contact switch unit 84 is turned on in step SC2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SC3, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SC4 and drives the bit moving motor 50 of the second drive unit 5 in step SC5.

[0151] When the bit moving motor 50 is driven to rotate in one direction, which is the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52, and the moving member 32 connected to the wire 54 by the second moving member 32c and the holding member 30 connected to the moving member 32 by the first moving member 32a move forward.

[0152] As a result, the driver bit 2 held by the holding member 30 moves forward as indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, and moves the screw 200 forward, pressing it against the object to be fastened.

[0153] When the bit rotation motor 40 is driven to rotate in the forward direction, the holding member 30 rotates together with the rotation guide member 31 .

[0154] 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 rotating the driver bit 2 with the first drive unit 4 to 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., so that the driver bit 2 follows the screw being screwed into the object to be fastened.

[0155] When the control unit 100 determines in step SC6 that the rotation speed of the bit moving 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, it stops driving the bit moving motor 50 in step SC7.

[0156] After stopping the driving of the bit moving motor 50 in step SC7, the control unit 100 determines in step SC8 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 has not risen in a direction away from the object to be fastened, and to end the fastening operation, the control unit 100 stops the rotation of the bit rotation motor 40 in the forward direction in step SC9 and reverses the rotation of the bit moving motor 50 in step SC10.

[0157] When the bit moving motor 50 rotates in the other direction, i.e., the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52, and the moving member 32 whose second moving member 32c is pushed by the biasing member 33 and the holding member 30 connected to the moving member 32 by the first moving member 32a move backward.

[0158] In step SC11, the control unit 100 reverses the rotation of the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SC12.

[0159] In step SC8, if the contact switch unit 84 is off, the control unit 100 determines that the fastening tool 1 is floating away from the object to be fastened, and continues to drive the bit rotation motor 40 to rotate in the forward direction while stopping the drive of the bit movement motor 50.

[0160] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction, further screwing it into the object to be fastened, and the fastening tool 1 moves in a direction approaching the object to be fastened. Therefore, the fastening tool 1 moves relatively to the contact arm 82, and the contact arm 82 presses the contact switch unit 84, turning the contact switch unit 84 on. When the contact switch unit 84 is on, the control unit 100 executes the processing of steps SC9 to SC12 described above to end the fastening operation, stops the bit rotation motor 40, and reverses the bit movement motor 50 to return the driver bit 2 to its standby position.

[0161] In addition, while the contact switch unit 84 is turned off and the drive of the bit moving motor 50 is stopped, the control unit 100 performs a control operation called a braking operation to prevent the bit moving motor 50 from rotating due to an external force while the bit rotating motor 40 is being rotated in the forward direction, thereby maintaining the holding member 30, 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.

[0162] However, while the bit moving motor 50 is stopped and the bit rotating motor 40 is being rotated in the forward direction, the fastening tool 1 is being pressed against the object to be fastened by the operator, thereby tightening the screw 200. Therefore, even if a braking operation is performed on the bit moving 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 rearward from the operation end position P2.

[0163] Therefore, in step SC13, the control unit 100 detects whether the bit moving motor 50 is rotating in the reverse direction, and if it detects that the bit moving motor 50 is rotating in the reverse direction, it returns to step SC5 and rotates the bit moving motor 50 in the forward direction, moving the holding member 30 and the moving member 32 forward and returning the driver bit 2 to the operation end position P2. Then, it stops the forward rotation of the bit moving motor 50 and performs a braking operation.

[0164] In order for the contact arm 82 to switch the contact switch unit 84 between on and off, the contact arm 82 must move a predetermined distance. Therefore, as described above, in step SC8, when the contact switch unit 84 is detected to be off and the bit moving motor 50 is stopped, the bit rotation motor 40 continues to be driven to rotate in the forward direction until the contact switch unit 84 switches from off to on, and the positions of the holding member 30 and the moving member 32 may fluctuate during the movement of the contact arm 82. Therefore, it is desirable to provide a detection unit that detects the position of the contact arm 82. A single motor may be used to rotate the bit holding unit 3 and move the bit holding unit 3 axially. The control unit 100 may control the timing of stopping the drive of the single motor based on whether the contact switch unit 84 is activated.

[0165] Fig. 21 is a flowchart showing another modified example of the operation of the fastening tool of this embodiment, and Figs. 22A and 22B are graphs showing the relationship between the load and the control of the bit rotation motor. Next, another modified example of the fastening operation of the fastening tool of this embodiment will be described with reference to these figures. In this modified example, the load applied to the bit rotation motor 40 is detected and the bit rotation motor 40 is controlled.

[0166] In the fastening tool 1, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0167] 21, the control unit 100 sets the rotation speed of the bit moving motor 50, which determines the advance amount of the driver bit 2, based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object to be fastened, the contact switch unit 84 is pressed by the contact arm 82, the contact switch unit 84 is turned on in step SD2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SD3, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SD4 and drives the bit moving motor 50 of the second drive unit 5 in step SD5.

[0168] When the bit moving motor 50 is driven to rotate in one direction, which is the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52, and the moving member 32 connected to the wire 54 by the second moving member 32c and the holding member 30 connected to the moving member 32 by the first moving member 32a move forward.

[0169] As a result, the driver bit 2 held by the holding member 30 moves forward as indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, and moves the screw 200 forward, pressing it against the object to be fastened.

[0170] When the bit rotation motor 40 is driven to rotate in the forward direction, the holding member 30 rotates together with the rotation guide member 31 .

[0171] 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 rotating the driver bit 2 with the first drive unit 4 to 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., so that the driver bit 2 follows the screw being screwed into the object to be fastened.

[0172] In step SD6, the control unit 100 determines whether the rotation speed of the bit moving 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 rotation speed of the bit moving motor 50 has not reached the set value selected by the setting unit 110, then in step SD7, the control unit 100 detects the load on the bit rotation motor 40, and if a predetermined load is detected, then the control unit 100 controls the bit rotation motor 40 in step SD8.

[0173] The rotation speed of the driver bit 2 varies depending on the magnitude of the load on the bit rotation motor 40, and 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 slower the rotation speed. Therefore, the control unit 100, as a fluctuation detection unit that detects 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, for example, lowering the voltage value applied to the bit rotation motor 40 or lowering the current value flowing through the bit rotation motor 40 when the load on the bit rotation motor 40 is lower compared to when the load is higher.

[0174] As a result, when the load on the bit rotation motor 40 is light, the rotation speed of the bit rotation motor 40 is reduced, thereby preventing the rotation speed from becoming higher than when the load is high, and preventing differences in the rotation speed of the bit rotation motor 40 due to the magnitude of the load on the bit rotation motor 40. Therefore, variations in the speed at which the screws 200 are fastened are prevented.

[0175] When the control unit 100 determines in step SD6 that the rotation speed of the bit moving 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, it stops driving the bit rotation motor 40 in step SD9, stops the rotation of the bit moving motor 50 in the forward direction in step SD10, and then reverses the rotation of the bit moving motor 50 in step SD11.

[0176] When the bit moving motor 50 rotates in the other direction, i.e., the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52, and the moving member 32 whose second moving member 32c is pushed by the biasing member 33 and the holding member 30 connected to the moving member 32 by the first moving member 32a move backward.

[0177] In step SD12, the control unit 100 reverses the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SD13.

[0178] In the control for reducing the output of the bit rotation motor 40, as shown in Fig. 22A, after a predetermined load is detected, the output may be reduced so that the number of rotations at which the driver bit 2 moves to the operation end position and the bit rotation motor 40 rotates are constant.Alternatively, as shown in Fig. 22B, after a predetermined load is detected, the output may be gradually reduced so that the number of rotations at which the driver bit 2 moves to the operation end position and the bit rotation motor 40 rotates are targeted.

[0179] Fluctuations in the power supply voltage cause differences in the rotation speed of the driver bit 2, with the lower the power supply voltage, the slower the rotation speed. Therefore, the control unit 100, which acts as a fluctuation detection unit that detects factors that cause fluctuations in the rotation speed of the bit rotation motor 40, detects the power supply voltage, and when the power supply voltage is high, the output of the bit rotation motor 40 is reduced compared to when the power supply voltage is low.

[0180] 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 preventing differences in the rotation speed of the bit rotation motor 40 caused by fluctuations in the power supply voltage. This prevents variations in the speed at which the screws 200 are fastened.

[0181] In addition, the control unit 100 may set a target rotation speed of the bit rotation motor 40, detect the rotation speed of the bit rotation motor 40, compare the detected rotation speed of the bit rotation motor 40 with a predetermined target rotation speed of the bit rotation motor 40, and control the bit rotation motor 40 so that the target rotation speed is achieved.

[0182] Now, reducing the rotational speed of the bit rotation motor 40 causes a decrease in the speed at which the screw is fastened into the object to be fastened. On the other hand, during the process of stopping the bit rotation motor 40 after the screw has been fastened to the target screw fastening depth set by the setting unit 110, the driver bit 2 continues to rotate, fastening the screw into the object to be fastened, until the rotation of the bit rotation motor 40 completely stops. For this reason, the faster the rotational speed of the bit rotation motor 40 immediately before it stops, the faster the screw will be fastened beyond the target.

[0183] Thus, the cause of the deterioration in the quality of the screw tightening operation due to the difference in rotation speed of the bit rotation motor 40 is the rotation speed immediately before the rotation of the bit rotation motor 40 stops. Therefore, the desired effect can be obtained if the rotation speed of the bit rotation motor 40 is constant, eliminating the influence of the load, immediately before the movement amount (advancement amount) of the holding member 30 and the moving member 32 reaches the target screw tightening depth set in the setting unit 110.

[0184] The load on the bit rotation motor 40 increases when the screw begins to be fastened into the object to be fastened, but the load varies depending on the material of the object to be fastened, etc. Therefore, after the load is detected as described above for controlling the rotation speed of the bit rotation motor 40, the rotation speed of the bit rotation motor 40 is controlled as described above based on the load, power supply voltage, etc., until the target screw fastening depth is reached.

[0185] It is also possible to provide a timer unit, and the control unit 100 may execute the above-described control of the rotation speed of the bit rotation motor 40 based on the load, power supply voltage, etc., after a predetermined time has elapsed since the start of driving (forward rotation) of the bit rotation motor 40. It is also possible to provide a position detection unit that detects the positions of the holding member 30 and the moving member 32, and execute the above-described control of the rotation speed of the bit rotation motor 40 based on the load, power supply voltage, etc., after the holding member 30 and the moving member 32 reach a predetermined position. The predetermined positions of the holding member 30 and the moving member 32, at which the control of the rotation speed of the bit rotation motor 40 is executed, 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 drive depth is reached.

[0186] Furthermore, in a method of setting a target rotational speed for the bit rotating motor 40 and controlling the output, it is possible that the target screw driving depth may be reached before the rotational speed of the bit rotating motor 40 decreases to the target rotational speed, due to factors such as the length of the control implementation period. Therefore, braking control of the bit rotating motor 40 may be performed during control to decrease the rotational speed of the bit rotating motor 40 to the target rotational speed. For example, if there is a large deviation between the target rotational speed of the bit rotating motor 40 and the detected actual rotational speed, braking control of the bit rotating 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 to decrease the rotational speed of the bit rotating motor 40 to the target rotational speed may be performed.

[0187] Furthermore, if the driver bit 2 disengages from the screw after reaching the target screw drive depth, the screw will not be further tightened even if the driver bit 2 rotates, so after the driver bit 2 has advanced until it reaches the target screw drive depth, the bit movement motor 50 may be rotated in the reverse direction before the rotation of the bit rotation motor 40 stops. Note that a single motor may be used to rotate the bit holder 3 and move the bit holder 3 in the axial direction, 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.

[0188] Fig. 23 is a flowchart showing another modified example of the operation of the fastening tool of this embodiment, Fig. 24A is a graph showing the relationship between the rotation speeds of the bit rotating motor and the bit moving motor under feedback (FB) control, and Fig. 24B is a graph showing the relationship between the movement speed of the screw caused by the rotation of the bit rotating motor under feedback (FB) control and the movement speed of the driver bit caused by the bit moving motor. Next, with reference to these figures, another modified example of the fastening operation of the fastening tool of this embodiment will be described. In this modified example, the movement speed of the screw caused by the rotation of the bit rotating motor 40 and the movement speed of the driver bit caused by the bit moving motor 50 are synchronized by feedback control.

[0189] In the fastening tool 1, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0190] 23, the control unit 100 sets the number of rotations of the bit moving motor 50, which determines the amount of advancement of the driver bit 2, based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object to be fastened, the contact switch unit 84 is pressed by the contact arm 82, the contact switch unit 84 is turned on in step SE2, the trigger 9 is operated, and the trigger switch unit 90 is turned on in step SE3, the control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SE4 and drives the bit moving motor 50 of the second drive unit 5 in step SE5.

[0191] When the bit moving motor 50 is driven to rotate in one direction, which is the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52, and the moving member 32 connected to the wire 54 by the second moving member 32c and the holding member 30 connected to the moving member 32 by the first moving member 32a move forward.

[0192] As a result, the driver bit 2 held by the holding member 30 moves forward as indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, and moves the screw 200 forward, pressing it against the object to be fastened.

[0193] When the bit rotation motor 40 is driven to rotate in the forward direction, the holding member 30 rotates together with the rotation guide member 31 .

[0194] 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 rotates the driver bit 2 with the first driving unit 4 in conjunction with the operation of screwing the screw into the object to be fastened, and moves the driver bit 2 forward with the second driving unit 5, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0195] In step SE6, the control unit 100 determines whether the rotation speed of the bit moving 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 rotation speed of the bit moving motor 50 has not reached the set value selected by the setting unit 110, then in step SE7, the control unit 100 detects the load on the bit moving motor 50, and if a predetermined load is detected, then in step SE8, the control unit 100 acquires the rotation speed of the bit rotation motor 40 and the rotation speed of the bit moving motor 50.

[0196] In step SE9, the control unit 100 calculates the rotational speeds of the bit rotation motor 40 and the bit moving motor 50 based on the rotational speed of the bit rotation motor 40, the rotational speed of the bit moving motor 50, the gear ratio of the reducer, etc., so that the movement speed of the screw 200 moving forward as the screw 200 is fastened into the object to be fastened by the rotation of the bit rotation motor 40, and the movement speed of the holding member 30 and the moving member 32 moving forward by the rotation of the bit moving motor 50, and the driver bit 2 attached to the holding member 30, are approximately equal as shown in Figure 24B.

[0197] In step SE10, the control unit 100 controls the bit moving motor 50 in this example by feedback control based on the rotation speed of the bit rotating motor 40, the rotation speed of the bit moving motor 50, the gear ratio of the reducer, etc. For example, the control is performed by increasing or decreasing the PWM output to the bit moving motor 50 to adjust the rotation speed.

[0198] When the control unit 100 determines in step SE6 that the rotation speed of the bit moving 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, it stops driving the bit rotation motor 40 in step SE11, stops the rotation of the bit moving motor 50 in the forward direction in step SE12, and then reverses the rotation of the bit moving motor 50 in step SE13.

[0199] When the bit moving motor 50 rotates in the other direction, i.e., the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52, and the moving member 32 whose second moving member 32c is pushed by the biasing member 33 and the holding member 30 connected to the moving member 32 by the first moving member 32a move backward.

[0200] In step SE14, the control unit 100 reverses the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SE15.

[0201] The above-mentioned feedback control is required after the screw 200 comes into contact with the object to be fastened and the load on the bit rotation motor 40 and bit movement motor 50 changes. Therefore, control when feedback control is not being performed is set to a first control mode, and control when feedback control is being performed is set to a 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. Then, 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 makes it possible to suppress delays in work time.

[0202] Furthermore, as a means for improving the responsiveness of feedback control and achieving more stable work quality, the acceleration / deceleration limit value for the bit movement motor 50 may be different between when feedback control is being executed after load detection and when feedback control is not being executed before load detection. Typically, when PWM output is performed on the motor, control is performed to limit the acceleration amount per unit time to stabilize the motor output, thereby preventing excessive acceleration current, especially at startup. However, if the above-described feedback control is performed while limiting the acceleration of the bit movement motor 50 at startup, the PWM output generated by the feedback control will be limited and applied to the bit movement motor 50, resulting in poor responsiveness to feedback control. Therefore, it is desirable to set the acceleration limit amount larger during feedback control than when the motor is started without feedback control.

[0203] Fig. 25 is a flowchart showing another modified example of the operation of the fastening tool of this embodiment, and Figs. 26A and 26B are graphs showing the relationship between the load and the control of the bit moving motor. Next, another modified example of the fastening operation of the fastening tool of this embodiment will be described with reference to these figures. In this modified example, the load applied to the bit moving motor 50 is detected and the bit moving motor 50 is controlled.

[0204] In the fastening tool 1, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0205] 25, the control unit 100 sets the rotation speed of the bit moving motor 50, which determines the advance amount of the driver bit 2, based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object to be fastened, 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 moving motor 50 of the second drive unit 5 in step SF5.

[0206] When the bit moving motor 50 is driven to rotate in one direction, which is the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52, and the moving member 32 connected to the wire 54 by the second moving member 32c and the holding member 30 connected to the moving member 32 by the first moving member 32a move forward.

[0207] As a result, the driver bit 2 held by the holding member 30 moves forward as indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, and moves the screw 200 forward, pressing it against the object to be fastened.

[0208] When the bit rotation motor 40 is driven to rotate in the forward direction, the holding member 30 rotates together with the rotation guide member 31 .

[0209] 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 rotates the driver bit 2 with the first driving unit 4 in conjunction with the operation of screwing the screw into the object to be fastened, and moves the driver bit 2 forward with the second driving unit 5, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0210] In step SF6, the control unit 100 determines whether the rotation speed of the bit moving 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 rotation speed of the bit moving motor 50 has not reached the set value selected by the setting unit 110, then in step SF7, the control unit 100 detects the load on the bit moving motor 50, and if a predetermined load is detected, then the control unit 100 controls the bit moving motor 50 in step SF8.

[0211] In order to prevent excessive impact when the screw 200 is pressed against the object to be fastened due to the holding member 30 and the moving member 32 moving forward as a result of the driving of the bit moving motor 50, the fastening speed is not reduced and the bit rotation motor 40 operates at the maximum output within the expected range, while the output of the bit moving motor 50 is limited by reducing the voltage value applied to the bit moving motor 50, reducing the current value flowing through the bit moving motor 50, etc.

[0212] When the ratio of the advancement amount of the driver bit 2 per rotation of the bit moving motor 50 to the advancement amount of the screw per rotation of the bit rotation motor 40 becomes low, cam-out occurs because the advancement amount of the driver bit 2 caused by the bit moving motor 50 cannot keep up with the advancement amount of the screw caused by the bit rotation motor 40. On the other hand, when the ratio of the advancement amount of the driver bit 2 per rotation of the bit moving motor 50 to the advancement amount of the screw per rotation of the bit rotation motor 40 becomes high, the advancement amount of the driver bit 2 caused by the bit moving motor 50 greatly exceeds the advancement amount of the screw caused by the bit rotation motor 40, and an excessive amount of force is required by the operator to press the fastening tool 1 toward the object to be fastened.

[0213] Therefore, it is preferable that the target value for the output limit be a ratio of the advancement amount of the driver bit 2 per one rotation of the bit moving motor 50 to the advancement amount of the screw per one rotation of the bit rotating motor 40, which is approximately 0.8 to 5 times. This prevents the occurrence of cam-out, and also prevents the operator from using excessive force to press the fastening tool 1 toward the object to be fastened, thereby preventing the occurrence of excessive impact when the screw 200 is pressed against the object to be fastened.

[0214] Furthermore, when the load on the bit moving motor 50 that occurs after the screw 200 comes into contact with the object to be fastened is detected, the output of the bit moving motor 50 is limited, thereby slowing down the holding member 30 and the moving member 32 when the screw 200 is pressed against the object to be fastened, thereby achieving a further impact suppression effect.

[0215] In controlling the output of the bit moving motor 50, as shown in FIG. 26A, the output of the bit moving motor 50 may be limited so that the bit moving motor 50 maintains a constant rotational speed until the bit rotation motor 40 rotates at a number of rotations that moves the driver bit 2 to the operation end position after a predetermined load is detected. Alternatively, as shown in FIG. 26B, the bit moving motor 50 is rotated forward at a first rotational speed until the predetermined load is detected. After the predetermined load is detected, the bit moving motor 50 is rotated forward at a second rotational speed, which is a lower rotational speed, to reduce the impact when the screw 200 is pressed against the object to be fastened. Furthermore, after a predetermined buffer time has elapsed during which the impact when the screw 200 is pressed against the object to be fastened is reduced, the output may be limited so that the bit rotation motor 40 maintains a constant rotational speed until the driver bit 2 moves to the operation end position at a third rotational speed that is slower than the first rotational speed but faster than the second rotational speed.

[0216] Fluctuations in the power supply voltage cause differences in the movement speed (advance speed) of the holding member 30 and the moving member 32, and the higher the power supply voltage, the faster the movement speed becomes, making it more likely that an 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 the higher the power supply voltage, the lower the output of the bit moving motor 50 compared to when the power supply voltage is low.

[0217] This prevents variations in the rotation speed of the bit moving motor 50 due to fluctuations in the power supply voltage, thereby preventing excessive impact when the screw 200 is pressed against the object to be fastened, and also preventing variations in the speed at which the screw 200 is pressed against the object to be fastened.

[0218] When the control unit 100 determines in step SF6 that the rotation speed of the bit moving 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, it stops driving the bit rotation motor 40 in step SF9, stops the rotation of the bit moving motor 50 in the forward direction in step SF10, and then reverses the rotation of the bit moving motor 50 in step SF11.

[0219] When the bit moving motor 50 rotates in the other direction, i.e., the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52, and the moving member 32 whose second moving member 32c is pushed by the biasing member 33 and the holding member 30 connected to the moving member 32 by the first moving member 32a move backward.

[0220] In step SF12, the control unit 100 reverses the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SF13.

[0221] 27 is a flowchart showing another modified example of the operation of the fastening tool of this embodiment, and next, another modified example of the fastening operation of the fastening tool of this embodiment will be described with reference to the drawings. In this modified example, the load on the bit moving motor 50, etc. is detected and driving in a state where there is no screw is suppressed.

[0222] In the fastening tool 1, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0223] 27, the control unit 100 sets the rotation speed of the bit moving motor 50, which determines the advance amount of the driver bit 2, based on the setting value selected by the setting unit 110. When the contact member 81 is pressed against the object to be fastened, the contact switch unit 84 is pressed by the contact arm 82, 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 moving motor 50 of the second drive unit 5 in step SG5.

[0224] When the bit moving motor 50 is driven to rotate in one direction, which is the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52, and the moving member 32 connected to the wire 54 by the second moving member 32c and the holding member 30 connected to the moving member 32 by the first moving member 32a move forward.

[0225] As a result, the driver bit 2 held by the holding member 30 moves forward as indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, and moves the screw 200 forward, pressing it against the object to be fastened.

[0226] When the bit rotation motor 40 is driven to rotate in the forward direction, the holding member 30 rotates together with the rotation guide member 31 .

[0227] 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 rotates the driver bit 2 with the first driving unit 4 in conjunction with the operation of screwing the screw into the object to be fastened, and moves the driver bit 2 forward with the second driving unit 5, thereby causing the driver bit 2 to follow the screw being screwed into the object to be fastened.

[0228] In step SG6, the control unit 100 determines whether the rotation speed of the bit moving 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 rotation speed of the bit moving motor 50 has not reached the set value selected by the setting unit 110, then in step SG7, the control unit 100 detects the load on either the bit rotation motor 40 or the bit moving motor 50, or both. When the control unit 100 detects a predetermined load due to the screw 200 being pressed against the object to be fastened, the control unit 100 continues to rotate the bit moving motor 50 in the forward direction until the rotation speed of the bit moving motor 50 reaches the set value selected by the setting unit 110.

[0229] When the control unit 100 determines in step SG6 that the rotation speed of the bit moving 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, it stops driving the bit rotation motor 40 in step SG8, ​​stops the rotation of the bit moving motor 50 in the forward direction in step SG9, and then reverses the rotation of the bit moving motor 50 in step SG10.

[0230] When the bit moving motor 50 rotates in the other direction, i.e., the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52, and the moving member 32 whose second moving member 32c is pushed by the biasing member 33 and the holding member 30 connected to the moving member 32 by the first moving member 32a move backward.

[0231] In step SG11, the control unit 100 reverses the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SG12.

[0232] When the bit rotation motor 40 and the bit movement motor 50 each rotate in the forward direction while the screw 200 is not present in the injection 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 the bit movement motor 50 does not increase. For this reason, even if the driver bit 2 attached to the holding member 30 moves forward a specified amount based on the length of the smallest screw 200 to be loaded, if a specified load is not detected, it can be determined that the screw 200 is not present.

[0233] Therefore, in step SG13, the control unit 100 determines whether the bit movement motor 50 has rotated a specified amount based on the length of the smallest screw 200 to be loaded, a specified amount for detecting idling that advances the driver bit 2 attached to the holding member 30. If the control unit 100 determines that the specified load has not been detected by either the bit rotation motor 40 or the bit movement motor 50, or both, and determines that the bit movement motor 50 has rotated the specified amount for detecting idling, it determines that there are no screws 200 and issues an error notification in step SG14. Furthermore, in the processing of steps SG8 to SG12 described above, the drive of the bit rotation motor 40 and the bit movement motor 50 is stopped.

[0234] The control unit 100 may detect the load on either the bit rotation motor 40 or the bit movement motor 50, or both, from changes in the current flowing through the motor, excluding changes in current that occur when the motor is started. Alternatively, the control unit 100 may detect the load on either the bit rotation motor 40 or the bit movement motor 50 from changes in the voltage flowing through the motor, excluding changes in voltage that occur when the motor is started. A single motor may be used to rotate the bit holder 3 and move the bit holder 3 axially, and the control unit 100 may detect the load on the single motor and suppress driving it when there is no screw.

[0235] Next, another modification of the fastening operation of the fastening tool of this embodiment will be described. To prevent malfunction, the fastening tool 1 starts a screw tightening operation when both the ON condition (when the contact arm 82 is turned on by pressing the contact member 81 against the workpiece) and the ON condition (when the trigger switch unit 90 is turned on by pulling the trigger 9) are satisfied. The contact arm 82 has a stroke from OFF to ON. To ensure reliable detection of the ON state of the contact arm 82, the contact arm 82 is configured to leave room for further depression from the ON state, taking into account variations in the assembly of the fastening tool. As a result, the positions of the contact member 81 and the contact arm 82 may vary within the stroke of the contact arm 82, even when the contact member 81 is in the same OFF or ON state. In such a case, for example, depending on the pressed position of the contact member 81, the screw tightening operation may be performed with the contact member 81 slightly raised relative to the tool body 10, causing the bearing surface of the screw head to lift off the surface of the workpiece, resulting in poor screw driving. Therefore, in this modified example, a technique is provided to eliminate fluctuations in the ON / OFF positions of the contact arm 82 due to variations in the assembly of the fastening tool 1, and to improve the ON / OFF accuracy of the contact arm 82.

[0236] 28 is a side view showing an example of a fastening tool according to a modified example. Note that in the fastening tool 1A of the modified example, the same reference numerals are used for the configurations common to the fastening tool 1 of the above embodiment, and the description of the fastening tool 1 is cited for the configurations and operations common to the above embodiment, thereby omitting or simplifying redundant description.

[0237] 28, the fastening tool 1A includes 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 axially moves the driver bit 2 held by the bit holding unit 3. The fastening tool 1A also includes a screw storage unit 6 that stores a screw 200 (see FIG. 1A), a nose unit 8 that is pressed against an object to be fastened and from which the screw 200 is ejected, a tool body 10, a handle 11 attached to the underside of the tool body 10, and a battery 12 detachably attached to the lower end of the handle 11.

[0238] The nose portion 8 includes an injection passage 80, an injection port 81a, a contact member 81 that contacts the object to be fastened, a contact arm 82 that moves in the forward and backward directions in conjunction with the contact member 81, and a magnet 82a that moves in conjunction with the contact arm 82.

[0239] 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 movement of the contact member 81. In the nose portion 8, the contact member 81 is urged forward by a urging member (not shown), and the contact member 81, which is pressed against the object to be fastened and moved rearward, is then urged forward by the urging member.

[0240] The fastening tool 1A has a magnet 82a at the rear end of the contact arm 82, facing the magnetic element 130, which moves in the front-to-rear directions indicated by arrows A1 and A2 in conjunction with the contact arm 82. For example, the magnet 82a may be attached to the rear end of the contact arm 82 as a separate member, or may be formed integrally with the rear end of the contact arm 82. In addition, although the rear end of the contact arm 82 is bifurcated in this embodiment, the magnet 82a may be attached to that position as an inseparable part.

[0241] The magnetic element 130 is provided on one side of the tool body 10 on which the contact arm 82 is provided, in a position facing the magnet 82a of the contact arm 82. The magnetic element 130 detects an analog amount of magnetic field generated from the magnet 82a of the contact arm 82, which moves in a direction toward the magnetic element 130 as the contact member 81 is pressed against the object to be fastened. The magnitude of the magnetic field detected by the magnetic element 130 differs depending on the distance between the magnet 82a provided on the contact arm and the magnetic element 130, so the position of the contact arm 82 relative to the magnetic element 130 can be detected by detecting the magnetic force of the magnet 82a.

[0242] Fig. 29 is a block diagram showing an example of the fastening tool 1A of the present embodiment. As shown in Fig. 29, in addition to the bit rotating motor 40, the bit moving motor 50, the trigger switch unit 90, and the setting unit 110, a magnetic element 130, and a recording unit 150 are connected to the control unit 100.

[0243] The magnetic element 130 detects the magnetic field generated from the magnet 82a attached to the contact arm 82, which is pushed toward the rear side of the tool body 10 in conjunction with the pressing action of the contact member 81 against the object to be fastened, and outputs a voltage proportional to the magnitude of the detected magnetic field to the control unit 100.

[0244] The control unit 100 acquires a voltage value based on the magnetic field of the magnet 82a output by the magnetic element 130. The control unit 100 has a threshold setting mode for calculating a threshold for determining whether the contact arm 82 is on or off, and calculates the threshold for determining whether the contact arm 82 is on or off using the acquired voltage value based on the magnetic field of the magnet 82a. The threshold setting mode may be selectable by the setting unit 110 provided in the tool body 10, or may be selectable by an operation unit separately provided in the tool body 10. Furthermore, the threshold setting mode may be selected and executed via wired or wireless communication from an information processing device such as a personal computer or tablet.

[0245] Furthermore, during the actual screw tightening operation, the control unit 100 acquires a voltage based on the magnetic field generated from the magnet 82a of the contact arm 82, which moves toward the rear of the tool body 10 in conjunction with the pressing action of the contact member 81 against the object to be fastened, and determines whether the contact arm 82 is on or off based on the result of comparing the acquired voltage value with the threshold calculated in the threshold setting mode. In other words, based on the on or off state of the contact arm 82, it determines whether to operate the bit rotation motor 40 etc. to start screw tightening, to deactivate it so that screw tightening does not start, or to end screw tightening.

[0246] The recording unit 150 records various data such as thresholds calculated in a threshold setting mode executed by the control unit 100. The recording unit 150 can be, for example, a magnetic storage device such as a hard disk drive (HDD), a semiconductor storage device, an optical storage device, or a magneto-optical storage device.

[0247] Next, an example of operation when the threshold setting mode is executed in the fastening tool 1A will be described. Fig. 30 is a flowchart showing an example of operation when the threshold setting mode is executed in the fastening tool 1A. Below, a case where the threshold setting mode is executed before shipping the fastening tool 1A will be described. The threshold setting mode is executed for each individual fastening tool.

[0248] As shown in FIG. 30, in step SH1, the fastening tool 1A presses the contact member 81 against the object to be fastened to a maximum depression position, which is an example of a reference position within the range in which the contact member 81 can be pressed against the object to be fastened. In this modified example, the maximum depression position is a position where the rear surface of the contact member 81 abuts against the front surface of the tool body 10. Note that the reference position may be other than the maximum depression position in which the contact member 81 can be pressed, and may be set to any position within the range (stroke) in which the contact member 81 can be pressed. Furthermore, the reference position may be one of a plurality of positions to which the contact member 81 is pressed in stages, or may be any position selected from a plurality of positions. Once the pressing of the contact member 81 against the object to be fastened is completed, the process proceeds to step SH2.

[0249] In step SH2, the magnetic element 130 detects the magnetic field generated by the magnet 82a, which has moved toward the rear of the tool body 10 together with the contact arm 82, and outputs a voltage proportional to the magnetic field to the control unit 100. Because there are variations in assembly between each fastening tool, the position (distance) of the magnet 82a relative to the magnetic element 130 varies between each fastening tool, and the magnitude of the voltage output from the magnetic element 130 of each fastening tool may also vary. The control unit 100 acquires the voltage value output from the magnetic element 130. After acquiring the voltage value, the process proceeds to step SH3.

[0250] In step SH3, the control unit 100 calculates a threshold value to be used when determining whether the contact arm 82 is on or off, based on the acquired voltage value. For example, the control unit 100 defines the position of the contact arm 82 when the contact member 81 is fully pushed rearward on the tool body 10 as a reference position O, and defines the forward position indicated by arrow A1 relative to the reference position O as the positive side, and calculates the voltage value at position α, which is +α mm forward of the reference position O (a position slightly forward of the position where the contact arm 82 is fully pushed in), as the threshold value. The threshold value may have a certain range. After calculating the threshold value, the process proceeds to step SH4.

[0251] In step SH4, the control unit 100 records the calculated threshold value in the recording unit 150. In this modified example, the threshold value setting mode is executed for each fastening tool taking into consideration the assembly variations in each fastening tool and the tolerances of each part, thereby calculating the threshold value for determining whether the contact arm 82 is turned on for each fastening tool, and storing the calculated threshold value in the recording unit 150 of each fastening tool.

[0252] Next, an example of the operation of the fastening tool 1B during screw tightening work will be described using the threshold value for determining whether the contact arm 82 is turned on, calculated and recorded in Fig. 30. Note that the basic operation in this case is the same as the operation shown in Fig. 19, so in this modified example, the explanation of the common operation will be omitted or simplified.

[0253] FIG. 31 is a flowchart showing a modified example of the operation of the fastening tool of this embodiment, and FIG. 32 is a graph showing the relationship between the position state of the contact arm and the control of the bit rotating motor and bit moving motor.

[0254] In the fastening tool 1B, in the standby state, the tip of the driver bit 2 is located at a standby position P1 behind the injection passage 80 as shown in FIG. 1A, and the screw 200 can be supplied to the injection passage 80.

[0255] In step SI1 of FIG. 31, the control unit 100 sets the number of rotations of the bit moving motor 50, which defines the advance amount of the driver bit 2, based on the set value selected by the setting unit 110.

[0256] When the operator presses the contact member 81 against the object to be fastened, the contact arm 82 and the magnet 82a attached to the contact arm 82 move toward the rear of the tool body 10. In step SI2, the magnetic element 130 detects the magnetic field of the magnet 82a attached to the contact arm 82 that has moved toward the rear of the tool body 10 and outputs a voltage proportional to the magnitude of the detected magnetic field. The control unit 100 compares the voltage value based on the magnetic field of the magnet 82a output from the magnetic element 130 with a threshold value calculated in advance in the threshold setting mode. If the voltage value is equal to or greater than the threshold value, the control unit 100 determines that the contact arm 82 is turned on. On the other hand, if the voltage value is less than the threshold value, the control unit 100 determines that the contact arm 82 is turned off. For example, as described above, if the voltage value at position α, which is +α mm from the reference position O, is set as the threshold value, when the contact arm 82 is pressed beyond position α of +α mm, the acquired voltage value exceeds the preset threshold value, and it is determined that the contact arm 82 is turned on.

[0257] In step SI3, when the contact arm 82 is on and the trigger switch unit 90 is turned on by operating the trigger 9, the control unit 100 proceeds to step SI4. The control unit 100 drives the bit rotation motor 40 of the first drive unit 4 in step SI4, and drives the bit movement motor 50 of the second drive unit 5 in step SI5.

[0258] When the bit moving motor 50 is driven to rotate in one direction, that is, the forward direction, the pulley 52 rotates in the forward direction, causing the wire 54 to be wound around the pulley 52, and the second moving member 32c moves 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, in the forward direction. As a result, the driver bit 2 held by the holding member 30 moves in the forward direction indicated by the arrow A1, engages with the screw 200 supplied to the injection port 81a of the nose portion 8, moves the screw 200 in the forward direction, and presses it against the object to be fastened.

[0259] Furthermore, when the bit rotation motor 40 is driven to rotate in one direction, that is, the forward 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 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., so that the driver bit 2 follows the screw being screwed into the object to be fastened.

[0260] When the control unit 100 determines in step SI6 that the rotation speed of the bit moving 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, it stops driving the bit moving motor 50 in step SI7.

[0261] After stopping the driving of the bit moving motor 50 in step SI7, the control unit 100 determines in step SI8 whether the contact arm 82 is on. Specifically, the control unit 100 determines whether the contact arm 82 is on based on whether the voltage value based on the magnetic field of the magnet 82a is equal to or greater than a preset threshold. If the contact arm 82 is on, the control unit 100 determines that the contact member 81 of the fastening tool 1A has not risen in a direction away from the fastening object, and to end the fastening operation, the control unit 100 stops the rotation of the bit rotation motor 40 in the forward direction in step SI9 and reverses the rotation of the bit moving motor 50 in step SI10.

[0262] When the bit moving motor 50 rotates in the other direction, i.e., the reverse direction, the pulley 52 rotates in the reverse direction, causing the wire 54 to be pulled out from the pulley 52, and the moving member 32 whose second moving member 32c is pushed by the biasing member 33 and the holding member 30 connected to the moving member 32 by the first moving member 32a move backward.

[0263] In step SI11, the control unit 100 reverses the bit moving motor 50 to the initial position where a predetermined amount of wire 54 is pulled out from the pulley 52, and when the holding member 30 and the moving member 32 move backward to a 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 moving motor 50 in step SI12.

[0264] In step SI8, when the contact arm 82 is off, the control unit 100 determines that the contact member 81 of the fastening tool 1A is floating away from the object to be fastened, and continues to drive the bit rotation motor 40 to rotate in the forward direction while stopping the drive of the bit movement motor 50.

[0265] As a result, the driver bit 2 held by the holding member 30 rotates the screw 200 in the forward direction, further screwing it into the object to be fastened, and the fastening tool 1A moves in a direction approaching the object to be fastened. As a result, the fastening tool 1A moves relative to the contact arm 82, and the control unit 100 determines that the contact arm 82 has been turned on. When the contact arm 82 is on, the control unit 100 executes the processing of steps SI9 to SI12 described above to end the fastening operation, stops the bit rotation motor 40, and reverses the bit movement motor 50 to return the driver bit 2 to its standby position.

[0266] Furthermore, when the voltage value based on the magnetic field of the magnet 82a is less than a preset threshold value, the control unit 100 determines that the contact arm 82 is off, and while stopping the drive of the bit moving motor 50, performs a control operation called a braking operation to prevent the bit moving motor 50 from rotating due to an external force while rotating the bit rotating motor 40 in the forward direction, thereby maintaining the holding member 30, the moving member 32, and the driver bit 2 held by the holding member 30 stopped at the operation end position P2.

[0267] However, while the bit rotation motor 40 is being rotated in the forward direction with the driving of the bit moving motor 50 stopped, the fastening tool 1A is being pressed against the object to be fastened by the operator, thereby tightening the screw 200. Therefore, even if a braking operation is performed on the bit moving 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 rearward from the operation end position P2.

[0268] Therefore, in step SI13, the control unit 100 detects whether the bit moving motor 50 is rotating in the reverse direction, and if it detects that the bit moving motor 50 is rotating in the reverse direction, as shown by the arrow in Figure 32, it returns to step SI5 and rotates the bit moving motor 50 in the forward direction, moving the holding member 30 and the moving member 32 forward and returning the driver bit 2 to the operation end position P2. Then, the forward rotation of the bit moving motor 50 is stopped and a braking operation is performed.

[0269] In the above embodiment, the threshold setting mode is executed before shipping of the fastening tool 1A. However, this is not limiting. For example, the threshold setting mode may be executed after shipping of the fastening tool 1A. This is because the assembly state of the fastening tool 1A may change after shipping, or the shapes of the contact member 81, contact arm 82, etc. may change due to deterioration over time caused by use of the tool. In such cases, the positions set as the ON positions of the contact member 81 and contact arm 82 may differ. Therefore, after using the fastening tool 1A for a certain period of time, the user may execute the threshold setting mode to recalculate and reset the threshold for the ON state of the contact arm 82.

[0270] Next, a modified example of the magnetic element 130, which is an example of the position detector described above, will be described. In the embodiment described above, the magnetic element 130 is used as the position detector that detects the position of the contact arm 82 that moves in conjunction with the pressing action of the contact member 81, but a distance sensor 140 can also be used instead of the magnetic element 130. When the position detector is configured as the distance sensor 140, it is not necessary to provide a magnet 82a at the end of the contact arm 82.

[0271] Fig. 33 is a block diagram showing an example of a fastening tool 1B according to the present embodiment. As shown in Fig. 33, a distance sensor 140 is connected to the control unit 100 in addition to a bit rotation motor 40, a bit movement motor 50, a trigger switch unit 90, a setting unit 110, and a recording unit 150.

[0272] The distance sensor 140 measures the distance, which is an analog quantity, between the rear end of the contact arm 82, which is pushed toward the rear side of the tool body 10 in conjunction with the pressing action of the contact member 81 against the fastening object, and outputs the measured distance information to the control unit 100. The distance measured by the distance sensor 140 corresponds to the position of the contact arm 82 relative to the distance sensor 140, so by measuring the distance of the contact arm 82, the position information of the contact member 81 and the contact arm 82 can be detected.

[0273] The control unit 100 acquires distance information based on the position of the rear end of the contact arm 82 output by the distance sensor 140. The control unit 100 has a threshold setting mode for calculating a threshold for determining whether the contact arm 82 is on or off, and calculates the threshold for determining whether the contact arm 82 is on or off using the acquired distance information of the contact arm 82. Furthermore, the control unit 100 acquires the distance between the contact arm 82, which moves toward the rear side of the tool body 10 in conjunction with the contact member 81 during actual screw tightening work, and determines whether the contact arm 82 is on or not based on the result of comparing the acquired distance information with the threshold calculated in the threshold setting mode.

[0274] 30 and 31 can be applied to processing using the distance sensor 140 of this modified example. That is, by replacing the magnetic element 130 with the distance sensor 140 and replacing the voltage value with distance information, the threshold setting mode shown in Fig. 30 and the operation during screw tightening work shown in Fig. 31 can be realized even when the distance sensor 140 is used.

[0275] Next, as a modified example of the magnetic element 130, which is an example of the position detection unit described above, it may be configured as a pressing force detection unit that detects the pressing force of the contact arm 82 that moves toward the rear side of the tool body 10 in conjunction with the pressing action of the contact member 81. In this case, too, for example, the pressing force of the contact arm 82 when the contact member 81 is pressed to the maximum may be set in advance as a threshold value, and during actual screw tightening, the pressing force detected by the pressing force detection unit due to the pressing of the contact arm 82 may be compared with the threshold value, and if the pressing force is equal to or greater than the threshold value, it may be determined that the contact arm 82 is on.

[0276] As described above, according to this modification, the position of the contact arm 82 when the contact member 81 is pushed to the maximum possible position is used as a reference, and the threshold is set based on the magnitude of the magnetic field of the magnet 82a attached to this contact arm 82. This increases the accuracy of the position at which the contact arm 82 is turned on or off, and the position at which the contact arm 82 is turned on can be adjusted to always be the same, making it possible to set the position at which the contact arm 82 is turned on for each individual fastening tool without being affected by variations in component dimensions or assembly. This makes it possible to eliminate variations in the on or off position of the contact arm 82, floating of the contact member 81, etc., even if there is variation in assembly between the fastening tools 1A and 1B, and makes it possible to provide fastening tools 1A and 1B with high precision for screw tightening work.

[0277] Although the preferred embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. For example, in the above-described embodiments, the contact member 81 and the contact arm 82 are configured as separate parts, but the present disclosure is not limited to this, and the contact member 81 and the contact arm 82 may be configured as a single part. [Explanation of symbols]

[0278] 1, 1A, 1B··· Fastening tool, 10··· Tool body, 10a··· Case, 10b··· Front frame, 10c··· Rear frame, 10d··· Joining member, 10e··· Screw, 10f··· Nose body portion, 11··· Handle, 12··· Battery, 13··· Battery mounting portion, 2··· Driver bit, 3··· Bit holding portion, 30··· Holding member, 30a··· Opening, 30b··· 1. Connecting member, 31... rotation guide member, 31a... groove portion, 32... moving member, 32a... first moving member, 32b... bearing (bearing), 32c... second moving member, 33... biasing member, 34a... bearing (bearing), 4... first driving portion, 40... bit rotation motor (motor, first motor), 40a... shaft, 41... reducer, 41a... shaft, 42... Bearing (bearing), 5... second drive unit, 50... bit moving motor (motor, second motor), 50a... shaft, 51... reducer, 51a... shaft, 52... pulley (transmission member), 53... bearing, 54... wire (transmission member), 6... screw storage unit, 7... screw feed unit, 70... screw feed motor, 71... pinion gear, 72... rack gear, 73... Engagement portion, 8... Nose portion, 80... Injection passage, 81... Contact member, 81a... Injection port, 82... Contact arm, 82a... Magnet, 83... Adjustment portion, 84... Contact switch portion, 9... Trigger, 90... Trigger switch portion, 100... Control portion, 110... Setting portion, 130... Magnetic element (position detection portion), 140... Distance sensor (position detection portion)

Claims

1. a bit holding portion that detachably holds a driver bit and is rotatable in a circumferential direction of the driver bit and movable in an axial direction; a motor that rotates the bit holding portion and moves the bit holding portion along an axial direction; a contact member that comes into contact with an object to be fastened by the screw engaged with the driver bit; a contact switch portion that is switched on and off depending on an axial movement amount of the contact member when the contact member comes into contact with the object to be fastened; a control unit that controls the timing to stop driving the motor based on whether the contact switch unit is on or off; A fastening tool comprising:

2. When the bit holding part moves to an operation end position along the axial direction, the control part determines whether the contact switch part is on or off, and when the contact switch part is off, the motor continues to rotate in one direction to fasten the screw. The fastening tool according to claim 1 .

3. The motor includes a first motor that rotates the bit holding portion; a second motor that moves the bit holding portion along the axial direction, The control unit controls the position of the bit holding unit along the axial direction by the number of rotations of the second motor. The fastening tool according to claim 1 .

4. The control unit rotates the first motor in one direction for fastening a screw and rotates the second motor in one direction for moving the bit holding unit in a direction toward the fastening object, and then controls the timing for stopping the driving of the first motor and the second motor based on the number of rotations of the second motor and on or off of the contact switch unit. The fastening tool according to claim 3 .

5. The control unit determines whether the contact switch unit is on or off when the second motor is rotated for a number of rotations at which the bit holding unit moves to the operation end position, and if the contact switch unit is off, continues to rotate the first motor in one direction. The fastening tool according to claim 3 or 4.

6. a bit holding portion that detachably holds a driver bit and is rotatable in a circumferential direction of the driver bit and movable in an axial direction; a motor that rotates the bit holding portion; a fluctuation detection unit that detects factors that cause fluctuations in the rotation speed of the motor; a control unit that performs control to suppress fluctuations in the rotation speed of the motor when the fluctuation detection unit detects a factor that causes fluctuations in the rotation speed of the motor; and A fastening tool comprising:

7. The fluctuation detection unit detects a factor that causes fluctuations in the rotation speed of the motor based on the magnitude of the load applied to the motor. The fastening tool according to claim 6.

8. The fluctuation detection unit detects factors that cause fluctuations in the rotation speed of the motor based on fluctuations in a power supply voltage. The fastening tool according to claim 6.

9. The motor includes a first motor that rotates the bit holding portion; a second motor that moves the bit holding portion along the axial direction, the fluctuation detection unit detects a factor that causes fluctuation in the rotation speed of the first motor, The control unit controls the axial position of the bit holding unit by the rotation speed of the second motor, and when the fluctuation detection unit detects a factor that causes fluctuations in the rotation speed of the first motor, performs control to suppress fluctuations in the rotation speed of the first motor. The fastening tool according to claim 6.

10. a bit holding portion that is rotatable in the circumferential direction of the driver bit and movable in the axial direction; a motor that rotates the bit holding portion and moves the bit holding portion along an axial direction; a trigger operably mounted to drive the motor; a contact member that comes into contact with an object to be fastened and is movable in the axial direction; a contact arm that is movable in the axial direction in conjunction with the contact member; a position detection unit that detects a position of the contact arm that has moved in response to contact of the contact member with the object to be fastened; a control unit that determines whether the contact arm is on or off based on the position of the contact arm detected by the position detection unit, drives the motor when both conditions of the trigger being on and the contact arm being on are satisfied, and controls the timing to stop driving the motor based on the on or off state of the contact arm.

11. The control unit determines whether the contact arm is on or off based on a comparison result between the position of the contact arm detected by the position detection unit and a threshold value set based on a reference position of the contact arm. The fastening tool according to claim 10.

12. The reference position is the position of the contact arm when the contact member is pressed most deeply into the object to be fastened. The fastening tool according to claim 11.

13. a magnet that moves in conjunction with the contact arm; the position detection unit is composed of a magnetic element that detects a magnetic field generated by the magnet, and outputs a voltage proportional to the magnitude of the magnetic field detected by the magnetic element to the control unit as position information of the contact arm; The control unit determines whether the contact arm is on or off based on a result of comparing the voltage with the preset threshold value. The fastening tool according to claim 12.

14. the position detection unit is configured with a distance sensor, measures the distance to the contact arm, and outputs the distance to the control unit as position information of the contact arm; The control unit determines whether the contact arm is on or off based on a comparison result between the distance and the preset threshold value. The fastening tool according to claim 12.

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