Electric fastening tool for bolt

Abstract

To provide an electric fastening tool for a bolt which can apply an appropriate fastening torque by distinguishing a torque difference by sockets between bolts with an equal head part diameter and different fastening torques.SOLUTION: An electric fastening tool for a bolt includes a tool socket which can mesh with a bolt head part, and changes a fastening torque in response to a type of the bolt head part. A core member for discrimination which is arranged so as to move in a rotation axis direction and contact with the bolt head part, a stopper mechanism which restricts movement of the core member for discrimination with respect to the rotation axis direction, and a control device for rotating the tool socket to fasten the bolt are included inside the tool socket. The control device adjusts the fastening torque of the bolt on the basis of a position of the core member for discrimination in the tool socket.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electric fastening tool having a tool socket used for fastening bolts, etc. [Background technology]

[0002] Many mechanical parts are used in machines such as automobiles and airplanes. The mechanical parts are assembled using, for example, bolts and nuts. When assembling the above-mentioned mechanical parts, the bolts and nuts are tightened using, for example, an electric fastening tool equipped with a tool socket.

[0003] The tightening torque of these bolts and nuts is set appropriately according to the type and characteristics of the machine parts to be fastened. Therefore, for example, when performing the above-mentioned assembly using multiple types of bolts, it is necessary to fasten them with an appropriate tightening torque according to the bolts.

[0004] For example, Patent Document 1 discloses a tool socket used to tighten or loosen a fastening part, which is a bolt having a hexagonal head or a hexagonal nut. Patent Document 1 proposes using a tool socket equipped with an inner socket and an outer socket to quickly determine whether a first fastening part or a second fastening part is set. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-94919 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, current technologies, including those described in the above patent documents, do not adequately meet market needs, and the following problems remain. Indeed, according to the above-mentioned Patent Document 1, it is possible to determine whether the first fastening part or the second fastening part is set in the tool socket depending on the position of the marker member in the direction of the rotation axis of the outer socket.

[0007] However, the configuration of the tool socket disclosed in Patent Document 1 is premised on the combination of an inner socket and an outer socket, and therefore the structure is complicated, which inevitably leads to increased costs. In the first place, Patent Document 1 distinguishes between two types of bolts (fastening parts 8A and 8B) with different head diameters, but it cannot be applied to bolts with the same head diameter but different tightening torques, and it can be said that there is room for improvement in the distinction for such bolts.

[0008] The present disclosure has been made in consideration of the above-mentioned problems as an example, and aims to provide an electric bolt tightening tool that can apply an appropriate tightening torque to bolts that have the same head diameter but different tightening torques by using a socket to clearly distinguish between the differences. [Means for solving the problem]

[0009] In order to solve the above problems, the electric bolt tightening tool of the present disclosure is an electric bolt tightening tool that has a tool socket that can engage with a bolt head and varies the tightening torque depending on the type of the bolt head, and is equipped with a discrimination core material that is arranged inside the tool socket so that it can move in the direction of a rotational axis and come into contact with the bolt head, a stopper mechanism that restricts the movement of the discrimination core material in the direction of the rotational axis, and a control device that rotates the tool socket to tighten the bolt, and the control device adjusts the tightening torque of the bolt based on the position of the discrimination core material in the tool socket. Effect of the Invention

[0010] According to the present disclosure, it is possible to apply an appropriate tightening torque to bolts having the same head diameter but different tightening torques by clearly distinguishing between the differences on the socket side. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a configuration of an electric fastening tool in a first embodiment. FIG. [Diagram 2] 10A and 10B are schematic diagrams for explaining state transitions of a discrimination core material in the electric fastening tool; [Diagram 3] FIG. 2 is a schematic diagram showing a mechanical part (bolt) suitable for the electric fastening tool of the present disclosure. [Figure 4] 11A to 11C are schematic diagrams showing state transitions of the electric fastening tool when a bolt having a bolt head with a recess is fastened. [Diagram 5] 1A to 1C are schematic diagrams showing state transitions (first half) of an electric fastening tool when a bolt having a bolt head with a flat upper surface is being fastened. [Figure 6] 11A to 11C are schematic diagrams showing the state transition (second half) of the electric fastening tool when a bolt having a bolt head with a flat upper surface is fastened. [Figure 7] FIG. 11 is a schematic diagram showing a configuration of an electric fastening tool according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, preferred embodiments for carrying out the present disclosure will be described. In addition, configurations other than those described in detail below can be implemented by appropriately supplementing known socket structures and equipment of power tools, including those described in Patent Document 1 above.

[0013] [First embodiment] <Electric fastening tools 100> First, the configuration of an electric fastening tool 100 in a first embodiment suitable for carrying out the present disclosure will be described with reference to Fig. 1. The electric fastening tool 100 in this embodiment has a function of fastening mechanical parts used in various machines. Note that there is no particular limitation on the machine suitable for this embodiment as long as the mechanical parts described below can be used, and examples thereof include various known industrial machines and machine tools such as automobiles, aircraft, and ships.

[0014] Similarly, there are no particular limitations on the mechanical parts suitable for this embodiment as long as they are parts that can be fitted into and fastened into the tool socket 10 described below. For example, multiple types of bolts 200 with the same head diameter but different tightening torques are suitable. More specifically, a bolt 200 as a mechanical part suitable for this embodiment is shown in Fig. 3. As can be seen from the figure, the bolt 200 includes a bolt head 210 into which the engaging recess 10c of the tool socket 10 described above fits (meshes for fastening), a flange portion 220 that expands in the radial direction at the lower end of the bolt head 210, and a threaded portion 230 that extends from the lower end of the flange portion 220.

[0015] Here, as shown in Fig. 3, the bolt head 210 may have the same head diameter but may be used with different tightening torque specifications. In this case, since it is necessary to distinguish the bolt 200 specifications on the basis of its external shape, the bolt 200 of this embodiment includes a first specification bolt 200a (with tightening torque set to a first value) in which a recess 210a is provided in the bolt head 210, and a second specification bolt 200b (with tightening torque set to a second value higher than the first value) in which the above-mentioned recess is not provided and the upper surface of the bolt head 210 is a flat portion 210b. In other words, the first specification bolt 200a and the second specification bolt 200b cannot be distinguished on the basis of their external shapes except for the head, and therefore, for example, an error (hereinafter also referred to as "misassembly") may occur when an operator assembles the bolt 200 to a machine.

[0016] In contrast, the electric fastening tool 100 of this embodiment includes a tool socket 10 that can mesh with the above-mentioned bolt head 210 , and is configured to have a function of varying the fastening torque depending on the type of this bolt head 210 . 1, the electric fastening tool 100 includes a tool socket 10, an actuator unit 20, and a control device 30. The electric fastening tool 100 may also include other known devices such as a liquid crystal display unit.

[0017] 1, the tool socket 10 includes a main body 10a that is rotatable about a rotation axis (the Z-axis in FIG. 1), an opening edge 10b, and an engagement recess 10c that is provided inside the opening edge 10b and into which a bolt head 210 can be inserted. Although not shown in the figure, a known connection end JP that engages with the actuator part 20 described above is provided on the side of the main body 10a opposite to the engagement recess 10c. The tool socket 10 of this embodiment can be manufactured, for example, by using a known 3D modeling technique using metal powder (also called a metal powder sintering 3D printer, powder bed fusion method, powder bed fusion bonding, or powder additive manufacturing method).

[0018] The tool socket 10 includes a discrimination core material 11, a stopper mechanism 12, and a detection sensor 13 inside the main body 10a. The discrimination core material 11 is disposed inside the main body 10a of the tool socket 10 so as to be movable in a direction parallel to the rotation axis direction and to be able to come into contact with the bolt head 210. That is, as shown in Fig. 1, the discrimination core material 11 of this embodiment is accommodated in an accommodation hole 11s provided in the main body 10a, and is configured as a columnar member having a tip portion 11t that can come into contact with the bolt head 210 and an end portion 11b that faces the bottom portion of the accommodation hole 11s of the main body 10a. As an example, the discrimination core material 11 may be a cylinder having a circular cross section, or a prism having a polygonal cross section.

[0019] As shown in Fig. 1, the end portion 11b of the discrimination core material 11 is connected to the bottom of the receiving hole 11s via a retraction member 11u. The retraction member 11u may be a known elastic member capable of elastic deformation, such as a compression coil spring. As a result, the discrimination core material 11 is biased so as to be pulled toward the bottom of the receiving hole 11s via the retraction member 11u.

[0020] 1, a positioning groove 12a is provided on the side surface of the discrimination core material 11 into which at least a portion of the retaining body 12b, which will be described later, can be inserted. As shown in the figure, the positioning groove 12a in this embodiment is provided on the outer circumferential surface of the discrimination core material 11 so as to continue along the circumferential direction. This allows the retaining body 12b to be stably inserted into the positioning groove 12a of the discrimination core material 11 accommodated in the accommodation hole 11s, as long as the position of the discrimination core material 11 in the rotation axis direction is matched, regardless of the rotation state of the discrimination core material 11 in the circumferential direction. With the above-mentioned configuration, by inserting a part of the holding body 12b into the positioning groove 12a, the movement of the discrimination core material 11 in the accommodation hole 11s in the direction parallel to the rotation axis direction is restricted.

[0021] The stopper mechanism 12 is configured to have a function of restricting movement in a direction parallel to the rotation axis direction of the discrimination core material 11. More specifically, as shown in Fig. 1 etc., the stopper mechanism 12 of this embodiment includes a positioning groove 12a provided on the outer circumferential surface of the discrimination core material 11, a retainer 12b at least a part of which is inserted into the positioning groove 12a to restrict movement of the discrimination core material 11 in the rotation axis direction (Z direction in the figure), a storage tunnel 12c provided in the tool socket 10 to store the retainer 12b movably in the radial direction, and an elastic member 12d provided in the storage tunnel 12c to bias the retainer 12b toward the positioning groove 12a.

[0022] In this embodiment, a sphere is preferable for the retaining body 12b, but it may also be a non-spherical shape including known polyhedrons such as a tetrahedron or hexahedron, so long as it is capable of being inserted into the positioning groove 12a and restricting the movement of the discrimination core material 11 in the direction of the rotation axis. In addition, the storage tunnel 12c is a recess provided along the radial direction so as to communicate with the above-mentioned storage hole 11s, but there is no particular restriction on the outer shape of the hole as long as the above-mentioned retaining body 12b can move along the radial direction inside it.

[0023] The detection sensor 13 is configured to have a function of detecting contact between the tip portion 11t of the discrimination core material 11 or the opening edge 10b of the tool socket 10 and the bolt 200. More specifically, the detection sensor 13 of this embodiment is configured to include a first detection sensor 13a, a second detection sensor 13b, and a third detection sensor 13c that are different from each other.

[0024] The first detection sensor 13a is installed on the tip 11t of the discrimination core material 11. The first detection sensor 13a is configured to have a function of detecting the presence or absence of contact between the tip 11t of the discrimination core material 11 and the bolt head 210. Examples of such a first detection sensor 13a include a contact type sensor such as a known pressure sensor equipped with a strain gauge, and a non-contact type sensor such as a known distance measuring sensor. The first detection sensor 13a is configured to be able to communicate with the control device 30 described later via wire or wirelessly.

[0025] The second detection sensor 13b is installed on the opening edge 10b of the main body 10a. The second detection sensor 13b is configured to have a function of detecting the presence or absence of contact between the opening edge 10b of the main body 10a and the flange portion 220 of the bolt 200. Examples of such a second detection sensor 13b include a contact type sensor such as a known pressure sensor equipped with a strain gauge, and a non-contact type sensor such as a known distance measuring sensor. The second detection sensor 13b is also configured to be able to communicate with the control device 30 described later via wire or wirelessly.

[0026] The third detection sensor 13c is installed at the bottom of the storage hole 11s in the main body 10a. The third detection sensor 13c functions as a so-called seating sensor and is configured to have a function of detecting the position of the end portion 11b of the discrimination core material 11 relative to the bottom portion of the storage hole 11s. The third detection sensor 13c may be provided on the end portion 11b of the discrimination core material 11 instead of the bottom portion of the storage hole 11s. As such a third detection sensor 13c, for example, a non-contact sensor such as a known distance measuring sensor is suitable. The third detection sensor 13c is also configured to be able to communicate with the control device 30 described later via wire or wirelessly.

[0027] The actuator unit 20 includes a known electric motor (not shown) and is configured to have a function of transmitting a driving force from the electric motor through the above-mentioned connection end JP to the tool socket 10 under the operation of an operator. As such an actuator unit 20, various known actuators disclosed in the above-mentioned patent documents may be used.

[0028] The control device 30 is configured to have a function of rotating the tool socket 10 to fasten the bolt 200. Furthermore, the control device 30 of this embodiment has a function of adjusting the fastening torque of the bolt 200 based on the position of the discrimination core material 11 in the tool socket 10. A specific example of such a control device 30 is a known computer device including one or more processors configured with a known CPU and one or more memories communicably connected to the one or more processors.

[0029] The control device 30 may also include a known storage device capable of storing a program capable of executing a torque setting method described below. Such a storage device may be, for example, a small hard disk, a flash memory, an SSD (Solid State Drive), or other media capable of storing a program.

[0030] <State transition of discrimination core material 11> Next, referring to Figure 2, we will explain the state transition of the discrimination core material 11 when fastening work is performed using multiple bolts (first specification bolts 200a and second specification bolts 200b) that have the same head diameter but different tightening torques. As can be seen from Figure 2, the discrimination core material 11 of this embodiment is positioned at a first position (tip protruding state) and a second position (core buried state) along the rotation axis direction depending on the shape of the bolt head 210 of the bolt 200.

[0031] 2(a) shows the discrimination core material 11 positioned in the first position (tip protruding state) described above. That is, at least a part of the retainer 12b is inserted into the positioning groove 12a of the discrimination core material 11 in the first position, and thus the discrimination core material 11 is fixed in the first position described above.

[0032] 2(b) shows a state where the discrimination core material 11 is positioned in the second position (core buried state) described above. That is, in the second position, the holder 12b is not inserted into the positioning groove 12a of the discrimination core material 11, and the discrimination core material 11 is thus pulled into the second position via the pulling member 11u described above.

[0033] <Fastening operation using first specification bolt 200a> Next, with reference to FIG. 4, a description will be given of the automatic torque adjustment when the operator uses the electric fastening tool 100 to fasten the first specification bolt 200a. First, as shown in FIG. 4(a), when an operator uses an electric fastening tool 100 to fasten a first specification bolt 200a, the operator lowers the insertion port 10d of the tool socket 10 toward the bolt so that the bolt head 210 engages with the engagement recess 10c of the tool socket 10.

[0034] At this time, since the bolt head 210 of the first specification bolt 200a is provided with a recess 210a, the tip 11t of the discrimination core material 11 is in a non-contact state within the recess 210a. Therefore, the control device 30 can detect that the tip 11t is in a non-contact state within the recess 210a based on the detection result from the first detection sensor 13a described above. In parallel, the control device 30 can detect that the opening edge 10b is in contact with the flange portion 220 based on the detection result from the second detection sensor 13b described above.

[0035] That is, the control device 30 controls the fastening torque output from the actuator unit 20 of the electric fastening tool 100 to a first value corresponding to the first specification bolt 200a based on the contact state of the tip portion 11t based on the first detection sensor 13a (in this example, ``non-contact state'') and the contact state of the opening edge 10b based on the second detection sensor 13b (in this example, ``contact state''), as shown in Table 1 below.

[0036] At this time, since the discrimination core 11 is maintained in the first position, the end portion 11b is separated from the bottom (this state is referred to as the "non-contact state" in the third detection sensor 13c), and the detection result by the third detection sensor 13c is the "non-contact state." Therefore, the control device 30 may set the above-mentioned fastening torque to a first value corresponding to the first specification bolt 200a, further taking into account the contact state of the end portion 11b by the third detection sensor 13c (the "non-contact state" in this example).

[0037] In this way, the control device 30 can detect the non-contact state between the tip 11t of the discrimination core material 11 and the bolt head 210, and the contact state between the opening edge 10b of the tool socket 10 and the flange portion 220 of the bolt 200 via the multiple detection sensors 13, and then perform control to set the fastening torque applied to the tool socket 10 to a first value.

[0038] <Fastening operation using the second specification bolt 200b> Next, with reference to FIGS. 5 and 6, a description will be given of the automatic torque adjustment when the operator uses the electric fastening tool 100 to fasten the second specification bolt 200b. First, as shown in FIG. 5(a), when an operator uses an electric fastening tool 100 to fasten a second specification bolt 200b, the operator lowers the tool socket 10 so that the bolt head 210 engages with the engagement recess 10c of the tool socket 10.

[0039] At this time, since the bolt head 210 of the second specification bolt 200b is provided with a flat portion 210b, the tip portion 11t of the discrimination core material 11 is in contact with the flat portion 210b. At this time, as shown in FIG. 5(b), the bolt head 210 and the engagement recess 10c are engaged (meshed) by a predetermined distance L. Furthermore, at this time, at least a part of the retainer 12b is still inserted into the positioning groove 12a and the discrimination core material 11 is maintained in the first position, so that the contact state of the opening edge 10b based on the second detection sensor 13b is in a "non-contact state". The control device 30 may determine the rotation mode described later by further taking into account the contact state of the end portion 11b based on the third detection sensor 13c (in this example, the "non-contact state").

[0040] Therefore, based on the detection results from at least the first detection sensor 13a and the second detection sensor 13b, the control device 30 can detect that the tip portion 11t is in contact with the flat portion 210b while the opening edge 10b is out of contact with the flange portion 220. Therefore, the control device 30 can execute control to rotate the tool socket 10 in a low rotation mode (first rotation speed) via the actuator unit 20 based on the detection results from the first detection sensor 13a and the second detection sensor 13b, as shown in Table 1 below.

[0041] Next, as shown in Fig. 6(a), the holding body 12b moves radially outward from the positioning groove 12a against the pressing force of the elastic member 12d due to the action of centrifugal force accompanying the rotation of the tool socket 10. Then, as shown in Fig. 6(b), the holding body 12b comes out of the positioning groove 12a, and the discrimination core material 11 moves to a second position along the rotation axis direction via the retraction member 11u.

[0042] As a result, as can be seen from the figure, the bolt head 210 is inserted deeper than the predetermined distance L into the engagement recess of the rotating tool socket 10, and the opening edge 10b of the tool socket 10 comes into contact with the flange portion 220. At this time, the control device 30 can detect the contact between the opening edge 10b and the flange portion 220 via the second detection sensor 13b. Note that the control device 30 may determine the rotation mode, which will be described later, by further taking into account the contact state of the end portion 11b detected by the third detection sensor 13c (in this example, the "contact state").

[0043] Therefore, as shown in Table 1 below, the control device 30 can execute control to change the tool socket 10 from the low rotation mode to the high rotation mode (a second rotation speed faster than the first rotation speed) via the actuator unit 20 based on the detection results from at least the first detection sensor 13a and the second detection sensor 13b. As a result, the control device 30 executes control to change the above-mentioned fastening torque to a value suitable for the second specification bolt 200b (a second value greater than the first value) after further detecting via the detection sensor 13 that the opening edge of the tool socket 10 has come into contact with the flange portion 220 of the bolt 200.

[0044] [Table 1]

[0045] Thus, in the electric fastening tool 100 of this embodiment, when fastening the first specification bolt 200a in which the fastening torque is set to the first value, the control device 30 detects, via the detection sensor 13, the non-contact state between the tip portion 11t of the discrimination core material 11 and the bolt head 210, and the contact state between the opening edge 10b of the tool socket 10 and the flange portion 220 of the bolt 200, and then executes control to set the fastening torque to the first value.

[0046] In addition, in the electric fastening tool 100 of this embodiment, when fastening the second specification bolt 200b, in which the fastening torque is set to the higher second value as described above, the control device 30 detects via the detection sensor 13 the contact state between the tip portion 11t of the discrimination core material 11 and the bolt head 210 and the non-contact state between the opening edge 10b of the tool socket 10 and the flange portion 220 of the bolt 200, and then first performs low-rotation mode control to rotate the tool socket 10 at a first rotational speed with the engagement recess 10c of the tool socket 10 and the bolt head 210 partially engaged (engaged by a predetermined distance L).

[0047] Next, after rotating the tool socket 10 at the first rotational speed described above and detecting via the detection sensor 13 the non-contact state between the tip 11t of the discrimination core material 11 and the bolt head 210 and the contact state between the opening edge 10b of the tool socket 10 and the flange portion 220 of the bolt 200, the control device 30 executes high rotation mode control to rotate the tool socket 10 at a faster second rotational speed.

[0048] In this way, according to the electric fastening tool 100 of this embodiment, by using the above-mentioned discrimination core material 11, stopper mechanism 12, and detection sensor 13, it is possible to clearly distinguish between bolts with the same head diameter but different tightening torques on the socket side and apply the appropriate tightening torque.

[0049] [Second embodiment] <Electric fastening tool 110> Next, an electric fastening tool 110 according to a preferred second embodiment of the present disclosure will be described. The electric fastening tool 110 according to the second embodiment is characterized mainly in that the configuration of the stopper mechanism 12 is different from that of the electric fastening tool 100 described above. Therefore, in the following second embodiment, elements having the same functions as those in the configuration of the electric fastening tool 100 described above are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0050] That is, in the stopper mechanism 12 in the electric fastening tool 110, the elastic member 12d is not connected to the above-mentioned holding body 12b, and the holding body 12b is supported by the holding plate 12e. Also, the holding plate 12e is provided in a plurality (e.g., about 5 to 6 pieces) discontinuously along the circumferential direction so as to surround the periphery of the discrimination core material 11, for example.

[0051] 7, the retaining plate 12e is configured to be movable in the radial direction within a retaining plate accommodating space 12f provided within the main body 10a. The retaining plate 12e is connected to an elastic member 12d installed within the retaining plate accommodating space 12f, and is capable of biasing the retaining body 12b into the positioning groove 12a via the elastic member 12d.

[0052] The tool socket 10 in the second embodiment can also be manufactured using, for example, a known 3D modeling technique using metal powder (also called a metal powder sintering 3D printer, powder bed fusion method, powder bed fusion bonding, or powder additive manufacturing method).

[0053] The stopper mechanism 12 according to the second embodiment described above can also achieve the same effects as those of the first embodiment. Furthermore, according to this embodiment, since a plurality of holding plates 12e can be provided intermittently along the circumferential direction, it is possible to provide a plurality of holding bodies 12b and support them with the corresponding holding plates 12e, for example.

[0054] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person having ordinary knowledge in the technical field to which the present disclosure belongs may attempt to further modify these embodiments and modifications within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

[0055] For example, the above-mentioned electric fastening tool 100 has been described as an example in which a single holding body 12b is used, but as in the second embodiment, the tool socket 10 may be constructed using not only a single holding body 12b but also multiple holding bodies 12b. In addition, in the above first and second embodiments, the detection results of at least the first detection sensor 13a and the second detection sensor 13b among the detection sensors 13 are used, but the above-mentioned fastening torque adjustment may also be performed using the detection results of at least the second detection sensor 13b and the third detection sensor 13c. [Explanation of symbols]

[0056] 100, 110 Electric fastening tools 10 Tool Socket 11 Identification core material 12 Stopper mechanism 13 Detection sensor 20 Actuator section 30 Control device

Claims

1. An electric fastening tool for bolts, comprising a tool socket capable of engaging with a bolt head, and capable of varying a fastening torque according to a type of the bolt head, a discrimination core member disposed inside the tool socket so as to be movable in the direction of a rotation axis and to be capable of contacting the bolt head; a stopper mechanism that restricts movement of the discrimination core material in the rotation axis direction; a control device that rotates the tool socket to tighten the bolt, The control device adjusts the tightening torque of the bolt based on the position of the discrimination core material in the tool socket. Electric fastening tool.

2. A detection sensor is further provided for detecting contact between the discrimination core material or the opening edge of the tool socket and the bolt, the control device detects, via the detection sensor, a non-contact state between the tip end of the discrimination core material and the head of the bolt, and a contact state between an opening edge of the tool socket and a flange portion of the bolt, and then sets the fastening torque to a first value. The electric fastening tool according to claim 1 .

3. the control device detects, via the detection sensor, a contact state between the tip end of the discrimination core material and the bolt head and a non-contact state between an opening edge of the tool socket and a flange portion of the bolt, and then rotates the tool socket at a first rotation speed in a state in which an engagement recess of the tool socket and the bolt head are partially engaged. The electric fastening tool according to claim 2 .

4. the control device rotates the tool socket at the first rotation speed, and after detecting, via the detection sensor, a non-contact state between the tip end of the discrimination core material and the bolt head, and a contact state between an opening edge of the tool socket and a flange portion of the bolt, rotates the tool socket at a second rotation speed faster than the first rotation speed. The electric fastening tool according to claim 3.

5. The stopper mechanism includes: A positioning groove provided on an outer peripheral surface of the discrimination core material; a holder that is at least partially inserted into the positioning groove and that restricts movement of the discrimination core material in the rotation axis direction; a receiving tunnel provided in the tool socket for receiving the holder so as to be movable in a radial direction; an elastic member provided in the accommodation tunnel for urging the holder into the positioning groove; The present invention relates to a method for manufacturing a semiconductor device comprising the steps of: The electric fastening tool according to any one of claims 1 to 4.

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