Impact rotary tool

Abstract

To inhibit abrasion powder produced between a hammer and an anvil from adhering to a circuit board.SOLUTION: An impact rotary tool 1 includes a motor 11, a hammer 12, an anvil 13, a sensor 14, a circuit board 15, and an isolator 10. The hammer 12 receives a rotational force around an axis from the motor 11 and outputs striking rotational force. The striking rotational force is obtained by converting part of the rotational force into a striking force around the axis. The anvil 13 is attached with a tip tool 2 and receives the striking rotational force from the hammer 12 to rotate, together with the tip tool 2, around the axis. The sensor 14 is provided in the vicinity of the anvil 13 and detects a state change of the anvil 13 changing according to the striking rotational force. The circuit board 15 is provided with a detection result by the sensor 14. The isolator 10 isolates contact portions 12a and 13b of the hammer 12 and the anvil 13 from at least the circuit board 15.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an impact rotary tool, and more particularly to an impact rotary tool including a hammer and an anvil, a sensor provided near the anvil, and a circuit board to which an output of the sensor is provided. [Background technology]

[0002] Patent Document 1 describes an electric power tool including a motor, an impact mechanism (hammer), an output shaft (anvil), a torque measuring unit (sensor), a tightening torque calculation unit, and a control unit (circuit board). The impact mechanism receives rotational force from the motor and applies an impact force, which is a pulsed rotational force that is generated by converting a portion of the rotational force, to the output shaft. The torque measuring unit measures the torque applied to the output shaft based on the distortion of the output shaft caused by the impact force. The tightening torque calculation unit calculates the tightening torque applied to the tightening member from the output shaft via the tool tip based on the measured torque. The control unit controls the motor based on the calculated tightening torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-70108 Summary of the Invention [Problem to be solved by the invention]

[0004] In rotary impact tools with the above-mentioned configuration, wear particles are generally generated at the contact point between the hammer and anvil due to the impact force. If conductive wear particles adhere to the circuit board, non-conductive parts may become conductive, potentially causing the operation of the rotary impact tool to become unstable.

[0005] In the power tool described in Patent Document 1, the tightening torque calculation unit and other components are housed in a case, which prevents wear particles from adhering to the tightening torque calculation unit and other components to a certain extent, but further prevention is required.

[0006] An object of the present disclosure is to provide a rotary impact tool that can suppress adhesion of wear powder generated between the hammer and anvil to a circuit board. [Means for solving the problem]

[0007] A rotary impact tool according to one aspect of the present disclosure includes a motor, a hammer, an anvil, a sensor, a circuit board, and an isolation unit. The hammer receives a rotational force about an axis from the motor and outputs an impact rotational force. The impact rotational force is obtained by converting a portion of the rotational force into an impact force about the axis. A tool bit is attached to the anvil, and the anvil receives the impact rotational force from the hammer and rotates together with the tool bit about the axis. The sensor is provided near the anvil and detects a change in the state of the anvil in response to the impact rotational force. The sensor's detection result is provided to the circuit board. The isolation unit isolates the contact portion between the hammer and the anvil from at least the circuit board. The isolation portion is a housing that covers at least the contact portion, and the circuit board is fixed to an outer surface of the housing. [Effects of the Invention]

[0008] The rotary impact tool of the present disclosure has the effect of suppressing adhesion of wear powder generated between the hammer and anvil to the circuit board. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an external view of a rotary impact tool according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of the rotary impact tool. [Figure 3] FIG. 3 is a side view showing the rotary impact tool with the first housing removed. [Figure 4]FIG. 4 is an exploded perspective view showing the rotary impact tool with the second housing removed. [Figure 5] FIG. 5 is a detailed view showing the inside of the sensor of the rotary impact tool. [Figure 6] FIG. 6 is a side view showing the rotary impact tool with the third housing removed. [Figure 7] FIG. 7A is a schematic diagram of the impact rotary tool of the same, FIG. 7B is a schematic diagram showing a first modified example of the impact rotary tool of the same, and FIG. 7C is a schematic diagram showing a second modified example of the impact rotary tool of the same. DETAILED DESCRIPTION OF THE INVENTION

[0010] The drawings described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios. Note that the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0011] (1) Overview As shown in FIGS. 1 to 4 and 7A, the rotary impact tool 1 according to the embodiment of the present disclosure includes a motor 11, a hammer 12, an anvil 13, a sensor 14, a circuit board 15, and an isolating unit 10.

[0012] (1-1) Motor, hammer and anvil The motor 11 receives power from a battery 16 (described later) and generates a rotational force about an axis 200. The hammer 12 receives the rotational force about the axis 200 from the motor 11 and outputs an impact rotational force. The impact rotational force is a part of the rotational force from the motor 11 converted into an impact force (pulse-like impact force) about the axis 200 (impact rotational force). The anvil 13 has the tool bit 2 attached, and receives the impact rotational force from the hammer 12 and rotates together with the tool bit 2 about the axis 200.

[0013] (1-2) Sensor The sensor 14 is provided near the anvil 13 and detects a change in the state of the anvil 13 in response to the impact rotational force generated by the hammer 12.

[0014] In this embodiment, the sensor 14 is a magnetostrictive sensor. Note that, as will be described in detail later, a magnetostrictive sensor is a sensor that magnetically detects the distortion of an object (here, the anvil 13).

[0015] However, the sensor 14 may be a strain sensor other than a magnetostrictive sensor (for example, a strain gauge that electrically detects strain, etc.) The sensor 14 may also be a sensor other than a strain sensor (for example, an acceleration sensor, etc.).

[0016] In this embodiment, the state change to be detected is a change in the strain of the anvil 13. However, the state change may be a change other than strain (for example, a change in the angular velocity of the anvil 13 around the axis 200, etc.).

[0017] (1-3) Circuit board The circuit board 15 is provided with the detection results of the sensor 14 .

[0018] In this embodiment, the sensor 14 and the circuit board 15 are electrically connected via a lead wire 14c. However, the sensor 14 and the circuit board 15 may be connected to each other so as to be able to communicate with each other via short-range wireless communication or the like.

[0019] In this embodiment, the circuit board 15 has an amplifier circuit 15a and a processing circuit 15b. The amplifier circuit 15a amplifies a signal indicating the detection result of the sensor 14 (for example, a voltage signal from a coil constituting a magnetostrictive sensor). The processing circuit 15b processes the voltage signal amplified by the amplifier circuit 15a (for example, converting it into a distortion signal, performing calculations to determine the tightening torque based on the distortion, etc.).

[0020] However, amplification of the voltage signal and conversion of the amplified voltage signal into a distortion signal may be performed within the sensor 14, and the circuit board 15 may only perform the calculation to determine the tightening torque based on the distortion.

[0021] (1-4) Isolation section The isolation portion 10 isolates the contact portion between the hammer 12 and the anvil 13 from at least the circuit board 15 .

[0022] The contact portion between the hammer 12 and the anvil 13 is a portion of the anvil 13 on which the impact rotational force from the hammer 12 acts, and a portion of the hammer 12 on which the reaction force from the anvil 13 acts.

[0023] The part of the anvil 13 on which the rotational impact force from the hammer 12 acts is the end (rear end: for example, anvil claw 13b) opposite to the end (tip end 13a) on which the bit 2 is attached. The part of the hammer 12 on which the reaction force from the anvil 13 acts is the part that comes into contact with the rear end of the anvil 13 (for example, hammer claw 12a that fits with anvil claw 13b).

[0024] That is, the contact portions between the hammer 12 and the anvil 13 are, for example, the hammer claw 12a and the anvil claw 13b, and will be hereinafter referred to as contact portions (12a, 13b).

[0025] In this way, the contact portions (12a, 13b), which are the source of wear particles, are isolated from the circuit board 15 by the isolation portion 10, so that adhesion of wear particles to the circuit board 15 can be suppressed.

[0026] (1-4-1) Housing In this embodiment, the isolation portion 10 is a housing 101. The housing 101 here is a member that covers at least the contact portions (12a, 13b). The circuit board 15 is disposed outside the housing 101.

[0027] In other words, the housing 101 surrounds only the space where the contact portions (12a, 13b) are present (hereinafter referred to as the first space S1), but does not surround the space where the circuit board 15 is present (hereinafter referred to as the second space S2). This isolates the contact portions (12a, 13b) from at least the circuit board 15.

[0028] In this way, the source of wear powder is covered by the housing 101 and the wear powder is kept within the housing 101, thereby preventing the wear powder from adhering to the circuit board 15 outside the housing 101.

[0029] In the rotary impact tool 1, the motor 11 is also usually arranged outside the housing 101. The rotary impact tool 1 in this embodiment further includes a battery 16, a control circuit 17, and a wireless communication circuit 18 (described later), and these elements are also arranged outside the housing 101.

[0030] In other words, the housing 101 surrounds only the first space S1, but does not surround the second space S2 or the space in which the motor 11 is located (hereinafter referred to as the third space S3). In this embodiment, the third space S3 further contains the battery 16, the control circuit 17, and the wireless communication circuit 18.

[0031] This isolates the contact portions (12a, 13b) not only from the circuit board 15 but also from the motor 11, the battery 16, the control circuit 17, the wireless communication circuit 18, and the like.

[0032] According to this embodiment, by covering the contact portions (12a, 13b), which are the source of wear debris, with a housing 101 (for example, the first housing 101: described below), which is one aspect of the isolation section 10, the wear debris remains within the housing 101, thereby preventing the wear debris from adhering to the circuit board 15 outside the housing 101.

[0033] In the power tool of Patent Document 1, the tightening torque calculation unit, etc., which corresponds to the circuit board 15, is covered with a cover, but in this case, the effect of suppressing adhesion of wear powder only extends to the tightening torque calculation unit, etc. In contrast, if the source of wear powder is covered and isolated with the housing 101 as in the present embodiment, the effect of suppressing adhesion of wear powder also extends to circuits other than the circuit board 15 (for example, the control circuit 17 and the wireless communication circuit 18, etc.).

[0034] (1-4-2) Wall However, the isolating unit 10 may be a wall 10a. The wall 10a here refers to a member that separates the space (hereinafter, referred to as the fourth space S4) in which the contact parts (12a, 13b) and the processing circuit 15b are present into a first space S1 in which the contact parts (12a, 13b) are present and a second space S2 in which the processing circuit 15b is present (see FIG. 7C). The wall 10a will be described in Modification 2.

[0035] In this case, the contact portions (12a, 13b) are isolated from the circuit board 15 by the wall 10a, which is another aspect of the isolation portion 10, and adhesion of wear powder to the circuit board 15 can be suppressed.

[0036] (2) Details In addition to the six elements (10 to 15) described above, the rotary impact tool 1 further includes a battery 16, a control circuit 17, and a wireless communication circuit 18, as shown in FIGS.

[0037] The battery 16 supplies power to the motor 11. The control circuit 17 controls the motor 11 based on the processing results of the processing circuit 15b, etc. The wireless communication circuit 18 performs wireless communication with an external device (not shown).

[0038] The isolation unit 10 in this embodiment is the housing 101 described above, specifically the first housing 101.

[0039] (2-1) First Housing The first housing 101 covers at least the contact portions (12a, 13b) between the hammer 12 and the anvil 13. The circuit board 15 is disposed outside the first housing 101. In this embodiment, the circuit board 15 is disposed inside the second housing 102 (described later), but is not limited to this.

[0040] The first housing 101 surrounds only the first space S1 in which the contact portions (12a, 13b) are present, and does not surround the second space S2 in which the circuit board 15 is present.

[0041] 2, 7A, etc., in the rotary impact tool 1 of this embodiment, the hammer 12, a portion of the anvil 13 excluding the tip portion 13a which is the end portion on the side where the bit 2 is attached, and the sensor 14 are present in the first space S1. Therefore, most of the hammer 12 and the anvil 13, and the sensor 14 are covered by the first housing 101.

[0042] In this way, by covering most of the hammer 12 and anvil 13, which are sources of wear debris, and the sensor 14 near the anvil 13, with the first housing 101, it is possible to protect the hammer 12, anvil 13, and sensor 14 while also preventing wear debris from adhering to the circuit board 15 outside the housing 101.

[0043] (2-2) Second Housing 1, 4, etc., the rotary impact tool 1 further includes a second housing 102. The second housing 102 is provided outside the first housing 101 and covers the circuit board 15.

[0044] The second housing 102 surrounds a second space S2 in which the circuit board 15 is present. In this embodiment, only the circuit board 15 is present in the second space S2, but members other than the circuit board 15 may also be present therein.

[0045] 4, 7A, etc., second housing 102 in this embodiment has one main surface 102c that is open. With circuit board 15 housed inside second housing 102, the open one main surface 102c side of second housing 102 is fixed to outer surface 101b of first housing 101.

[0046] In detail, as shown in FIG. 4, the impact rotary tool 1 further includes four screws 102b, four screw holes 101a are formed on the outer surface 101b of the first housing 101, and four through holes 102a are formed in the second housing 102.

[0047] As shown in FIG. 2 and other figures, the circuit board 15 is disposed on the outer surface 101b of the first housing 101, and is connected to the sensor 14 inside the first housing 101 by a lead wire 14c.

[0048] The four screws 102b pass through the four through holes 102a of the second housing 102 and are fastened to the four screw holes 101a in the outer surface 101b of the first housing 101. This fixes the open one main surface 102c of the second housing 102 to the outer surface 101b of the first housing 101.

[0049] In this embodiment, the second housing 102 is detachably attached to the outer surface 101b of the first housing 101 by the four screws 102b. However, the second housing 102 may be fixed to the outer surface 101b of the first housing 101 with an adhesive or the like.

[0050] In this embodiment, in addition to covering the hammer 12 and most of the anvil 13 and the sensor 14 near the anvil 13 with the first housing 101, as described above, the circuit board 15 is covered with the second housing 102, which more effectively prevents wear debris from adhering to the circuit board 15.

[0051] Note that one main surface 102c of second housing 102 does not have to be open (see Modification 1). Also, second housing 102 may cover first housing 101 in addition to circuit board 15 (see other modifications).

[0052] (2-3) Circuit board (2-3-1) Circuit board layout The circuit board 15 is fixed to the outer surface 101 b of the first housing 101 .

[0053] The circuit board 15 is fixed to the outer surface 101b of the first housing 101 by, for example, the second housing .

[0054] As described above, the second housing 102 in this embodiment has one main surface 102c open, and the circuit board 15 is fixed directly to the outer surface 101b of the first housing 101 while housed in the second housing 102, as shown in Figures 4 and 7A, etc.

[0055] More specifically, circuit board 15 is disposed on outer surface 101b of first housing 101, and second housing 102 covers it with one open main surface 102c fixed to outer surface 101b of first housing 101. In other words, circuit board 15 is sandwiched between outer surface 101b of first housing 101 and inner surface 102d of second housing 102, and fixed to outer surface 101b of first housing 101.

[0056] Therefore, according to the second housing 102 of this embodiment, the circuit board 15 can be fixed directly to the first housing 101, and adhesion of wear powder to the circuit board 15 can be suppressed.

[0057] Furthermore, by fixing the circuit board 15 to the outer surface 101b of the housing 101, it is possible to shorten the distance between the sensor 14 and the circuit board 15. In this embodiment, the sensor 14 and the circuit board 15 are connected by the lead wire 14c, which shortens the length of the lead wire 14c.

[0058] Furthermore, as a result of fixing the circuit board 15 to the outer surface 101b of the first housing 101, the sensor 14 inside the first housing 101 and the circuit board 15 on the outer surface 101b of the first housing 101 vibrate together with the first housing 101 in response to the impact rotational force from the hammer 12, thereby suppressing the tension generated in the lead wire 14c.

[0059] The connection between the sensor 14 and the circuit board 15 is not limited to a wired connection via the lead wire 14c, but may be a wireless connection, in which case the wireless communication distance can be shortened.

[0060] (2-3-2) Circuit board configuration The circuit board 15 includes a processing circuit 15b, which processes the detection results of the sensor 14.

[0061] As described above, the sensor 14 in this embodiment is a magnetostrictive sensor, and the processing circuit 15b processes a voltage signal from a coil 14b (described later) that constitutes the magnetostrictive sensor.

[0062] In this embodiment, the circuit board 15 further includes an amplifier circuit 15a. The amplifier circuit 15a amplifies the voltage signal from the coil 14b and provides the amplified voltage signal to a processing circuit 15b. The processing circuit 15b processes the voltage signal amplified by the amplifier circuit 15a.

[0063] More specifically, the processing circuit 15b converts the amplified voltage signal into a distorted signal that changes in accordance with the distortion.

[0064] In this way, the voltage signal from the coil 14b constituting the magnetostrictive sensor 14 is amplified by the circuit board 15 and then converted into a strain signal, thereby making it possible to magnetically detect the strain of the anvil 13.

[0065] Furthermore, the processing circuit 15b performs a calculation to determine the tightening torque based on the strain indicated by the strain signal. The tightening torque is the torque around the axis 200 that is applied to the tightening member such as a screw from the anvil 13 via the tool bit 2.

[0066] The processing result of the processing circuit 15b is given to the control circuit 17. The processing circuit 15b and the control circuit 17 are also usually connected by wire, but may be connected wirelessly.

[0067] (2-4) Third Housing The rotary impact tool 1 further includes a third housing 103 .

[0068] The third housing 103 is provided outside the first housing 101 and outside the second housing 102 and covers at least the motor 11 .

[0069] The third housing 103 in this embodiment surrounds a third space S3 in which the motor 11 and the like are located. In the rotary impact tool 1, as shown in FIG. 2, a battery 16, a control circuit 17, a wireless communication circuit 18, and the like are further located in the third space S3.

[0070] Therefore, the third housing 103 also covers the battery 16, the control circuit 17, the wireless communication circuit 18, and the like that are present in the third space S3.

[0071] By covering the motor 11 and other components with the third housing 103 in this manner, it is possible to prevent wear powder generated at the contact portions (12a, 13b) between the hammer 12 and the anvil 13 from adhering to the motor 11 and other components.

[0072] Depending on the type of motor 11, wear powder may be generated, for example, due to friction between the brush and the commutator. However, by covering the motor 11 with the third housing 103, it is possible to prevent this type of wear powder from adhering to the circuit board 15.

[0073] In this embodiment, the control circuit 17 and the wireless communication circuit 18 are arranged in the third space S3 (inside the third housing 103), but at least one of the control circuit 17 and the wireless communication circuit 18 may be arranged in the second space S2 (inside the second housing 102). In other words, both or one of the control circuit 17 and the wireless communication circuit 18 may be components of the circuit board 15.

[0074] (2-5) Sensor The sensor 14 in this embodiment is a magnetostrictive sensor, and will hereinafter be referred to as the "magnetostrictive sensor 14." The magnetostrictive sensor 14 magnetically detects the distortion of the anvil 13 and outputs a signal according to the detection result.

[0075] 5, the magnetostrictive sensor 14 includes a magnetostrictive film 14a and a coil 14b. The magnetostrictive film 14a is formed on at least a part of the outer peripheral surface 13c of the anvil 13, and the coil 14b is disposed so as to surround the magnetostrictive film 14a.

[0076] In this embodiment, the magnetostrictive film 14a is formed, for example, as shown in Figure 2, slightly toward the rear (toward the anvil claws 13b) of the outer peripheral surface 13c of the anvil 13, over a range of approximately one-third to one-quarter of the length of the anvil 13.

[0077] The magnetostrictive film 14a is formed by, for example, spraying a magnetostrictive material such as ferrite onto the anvil 13. However, the type of magnetic material and the method for forming the magnetostrictive film 14a are not critical.

[0078] When the anvil 13 is distorted by the torque of the hammer 12, stress from the anvil 13 is applied to the magnetostrictive film 14a, causing a change in the magnetic permeability of the magnetostrictive film 14a. When the magnetic permeability of the magnetostrictive film 14a changes, the impedance of the coil 14b changes due to the inverse magnetostrictive effect. A voltage signal corresponding to this change in impedance is output from the coil 14b.

[0079] As described above, the voltage signal from the coil 14b is applied to the circuit board 15, amplified by the amplifier circuit 15a, and then converted into a distorted signal by the processing circuit 15b.

[0080] In this way, the voltage signal from the coil 14b constituting the magnetostrictive sensor 14 is amplified by the circuit board 15 and converted into a strain signal, so that the strain of the anvil 13 can be magnetically detected.

[0081] The processing circuit 15b also performs calculations to determine the tightening torque based on the strain. The tightening torque is the torque around the axis 200 that is applied from the anvil 13 via the tool bit 2 to the tightening member such as a screw.

[0082] In this way, by performing calculations on the circuit board 15, the tightening torque applied to the tightening part by the tool bit 2 attached to the anvil 13 can be calculated based on the distortion of the anvil 13.

[0083] (3) Variation 1 7A , in the rotary impact tool 1 in the above-described embodiment, one main surface 102c of the second housing 102 is open, and the circuit board 15 is directly fixed to the outer surface 101b of the first housing 101 by the inner surface 102d of the second housing 102. In other words, the circuit board 15 in the embodiment is covered by a part of the first housing 101 and the second housing 102.

[0084] In contrast, in the impact rotary tool 1 in this modified example 1, as shown in Figure 7B, none of the surfaces of the second housing 102 are open, and the circuit board 15 is fixed to the outer surface 101b of the first housing 101 with the entire circuit board 15 covered by the second housing.

[0085] In the first modification, the effect of preventing adhesion of wear particles to the circuit board 15 can be obtained, similar to the embodiment.

[0086] (4) Variation 2 In the rotary impact tool 1 of the second modification, the isolation portion 10 is a wall 10a as shown in FIG. 7C.

[0087] The wall 10a separates the space within the fourth housing 104 (hereinafter referred to as the fourth space S4) that covers the hammer 12, the end (tip portion 13a) of the anvil 13 on which the tip tool 2 is attached, and the circuit board 15, into the first space S1 and the second space S2.

[0088] In this way, by separating the fourth space S4 into the first space S1 and the second space S2 by the wall 10a, the contact portions (12a, 13b) are isolated from the circuit board 15, thereby preventing wear debris from adhering to the circuit board 15.

[0089] (5) Other variations In the rotary impact tool 1 according to another modification, the second housing 102 covers the first housing 101 in addition to the circuit board 15 .

[0090] That is, the hammer 12 and most of the anvil 13 and the sensor 14 near the anvil 13 are covered by the first housing 101, and the first housing 101 together with the circuit board 15 are covered by the second housing 102.

[0091] In this case as well, the contact portions (12a, 13b), which are the source of wear debris, are covered by the first housing 101 and isolated from the circuit board 15, thereby preventing the adhesion of wear debris to the circuit board 15. Furthermore, the processing circuit 15b is doubly covered by the first housing 101 and the second housing 102, thereby more effectively protecting the processing circuit 15b.

[0092] (6) Summary A rotary impact tool (1) according to a first aspect includes a motor (11), a hammer (12), an anvil (13), a sensor (14), a circuit board (15), and an isolation unit (10). The hammer (12) receives a rotational force about an axis (200) from the motor (11) and outputs an impact rotational force. The impact rotational force is obtained by converting a portion of the rotational force into an impact force about the axis (200). The anvil (13) has a tool bit (2) attached thereto, receives the impact rotational force from the hammer (12), and rotates together with the tool bit (2) about the axis (200). The sensor (14) is provided near the anvil (13) and detects a change in the state of the anvil (13) in response to the impact rotational force. The circuit board (15) receives the detection result of the sensor (14). The isolation portion (10) isolates contact portions (12a, 13b) between the hammer (12) and the anvil (13) from at least the circuit board (15).

[0093] According to this embodiment, the contact portions (12a, 13b) between the hammer (12) and the anvil (13), which are the source of wear powder, are isolated from at least the circuit board (15), thereby preventing wear powder from adhering to the circuit board (15).

[0094] In the impact rotary tool (1) according to the second aspect, in the first aspect, the isolation part (10) is a housing (101) that covers at least the contact parts (12a, 13b), and the circuit board (15) is arranged outside the housing (101).

[0095] According to this embodiment, the source of the wear powder is covered with the housing (101) and the wear powder is trapped within the housing (101), thereby preventing the wear powder from adhering to the circuit board (15) outside the housing (101).

[0096] In the rotary impact tool (1) according to the third aspect, the circuit board (15) is fixed to the outer surface (101b) of the housing (101) in the second aspect.

[0097] According to this embodiment, it is possible to shorten the distance between the sensor 14 and the circuit board 15. For example, if the sensor 14 and the circuit board 15 are connected by a lead wire 14c, the length of the lead wire 14c can be shortened. Furthermore, since the circuit board 15 on the outer surface 101b of the housing 101 and the sensor 14 inside the housing 101 vibrate together in response to the rotational impact force from the hammer 12, it is possible to suppress the tension generated in the lead wire 14c.

[0098] In the impact rotary tool (1) according to the fourth aspect, in the third aspect, the housing (101) covers the hammer (12), the anvil (13) except for the tip portion (13a) which is the end portion on which the tip tool (2) is attached, and the sensor (14).

[0099] According to this embodiment, by covering most of the hammer (12) and anvil (13), which are sources of wear powder, and the sensor (14) near the anvil (13), with the housing (101, it is possible to protect most of the hammer (12) and anvil (13) and the sensor (14) while suppressing the adhesion of wear powder to the circuit board (15) outside the housing (101).

[0100] When the circuit board 15 is covered with a cover or the like, the effect of suppressing adhesion of wear powder only extends to the circuit board 15, but when the source of wear powder is covered with the housing 101 and isolated from the circuit board 15 as in this embodiment, the effect of suppressing adhesion of wear powder generally extends to elements other than the circuit board 15 (such as the control circuit 17), thereby making it possible to suppress adhesion of wear powder to elements other than the circuit board 15.

[0101] In the rotary impact tool (1) according to the fifth aspect, the housing (101) in the fourth aspect is the first housing (101). The rotary impact tool (1) further includes a second housing (102). The second housing (102) is provided outside the first housing (101) and covers the circuit board (15).

[0102] According to this embodiment, by covering the contact parts (12a, 13b), which are the source of wear powder, with the first housing (101) and covering the circuit board (15) with the second housing (102), adhesion of wear powder to the circuit board (15) can be more effectively suppressed.

[0103] In the rotary impact tool (1) according to the sixth aspect, in the fifth aspect, the second housing (102) has an open main surface (102c). With a circuit board (15) housed inside, the second housing (102) has the open main surface (102c) fixed to the outer surface (101b) of the first housing (101). The circuit board (15) is fixed to the first housing (101) by the outer surface (101b) of the first housing (101) and the inner surface (102d) of the second housing (102).

[0104] According to this embodiment, the second housing (102) can fix the circuit board (15) to the first housing (101) and also prevent wear particles from adhering to the circuit board (15).

[0105] The rotary impact tool (1) according to a seventh aspect is the sixth aspect, further including a third housing (103). The third housing (103) is provided outside the first housing (101) and outside the second housing (102), and covers at least the motor (11).

[0106] According to this embodiment, by covering the motor (11) and the like with the third housing (103), it is possible to suppress adhesion of wear powder generated at the contact portions (12a, 13b) between the hammer (12) and the anvil (13) to the motor (11), etc. Furthermore, even if wear powder is generated in the motor (11) due to friction between a brush and a commutator, for example, it is possible to suppress adhesion of the wear powder to the circuit board (15).

[0107] In the rotary impact tool (1) according to an eighth aspect, in any of the first to seventh aspects, the sensor (14) detects distortion of the anvil (13) and outputs a signal corresponding to the detection result. The circuit board (15) has a processing circuit (15b). The processing circuit (15b) performs calculation processing to determine the tightening torque using the output signal of the sensor (14). The tightening torque is the torque around the shaft (200) applied to the tightening member from the anvil (13) via the bit (2).

[0108] According to this embodiment, the tightening torque can be calculated based on the strain of the anvil (13).

[0109] A rotary impact tool (1) according to a ninth aspect is the same as that of the eighth aspect, except that the sensor (14) has a magnetostrictive film (14a) and a coil (14b). The magnetostrictive film (14a) is formed on at least a portion of the outer circumferential surface (13c) of the anvil (13). The coil (14b) is disposed so as to surround the magnetostrictive film (14a). The circuit board (15) further includes an amplifier circuit (15a), which amplifies a voltage signal from the coil (14b) and provides the amplified voltage signal to a processing circuit (15b).

[0110] According to this embodiment, the distortion of the anvil (13) can be detected magnetically. [Explanation of symbols]

[0111] 1. Rotary impact tool 10 Isolation section 11 Motor 12 Hammer 12a Contact part (hammer claw) 13 Anvil 13a Tip 13b Contact part (anvil claw) 13c Outer surface 14 Sensors 14a Magnetostrictive film 14b coil 14c lead wire 15 Circuit Board 15a Amplifier circuit 15b Processing circuit 101 1st Housing (Housing) 101b External surface 102 Second Housing 102c One main surface 102d Inside 103 Third Housing 104 4th Housing 10a Wall 2 Tip tool

Claims

1. A motor; a hammer that receives a rotational force around an axis from the motor, converts a part of the rotational force into an impact force around the axis, and outputs the impact rotational force; an anvil to which a tool bit is attached and which receives the impact rotational force from the hammer and rotates together with the tool bit around the axis; a sensor provided near the anvil for detecting a change in state of the anvil in response to the impact rotational force; a circuit board to which the detection results of the sensor are provided; an isolation portion that isolates a contact portion between the hammer and the anvil from at least the circuit board, the isolation portion is a housing that covers at least the contact portion, The circuit board is fixed to the outer surface of the housing. Rotary impact tool.

2. The housing covers the hammer, the anvil except for the tip end, which is the end on the side where the tip tool is attached, and the sensor. The rotary impact tool according to claim 1 .

3. The housing is a first housing, a second housing provided outside the first housing and covering the circuit board; The rotary impact tool according to claim 2.

4. The second housing is On the other hand, the main surface is open, With the circuit board housed inside, the open one main surface side is fixed to an outer surface of the first housing, the circuit board is fixed to the first housing by the outer surface of the first housing and the inner surface of the second housing; The rotary impact tool according to claim 3.

5. Further comprising a third housing provided outside the first housing and outside the second housing, and covering at least the motor. The rotary impact tool according to claim 4.

6. The sensor detects distortion of the anvil and outputs a signal according to the detection result, The circuit board has a processing circuit that performs arithmetic processing to determine the tightening torque around the axis that is applied to the tightening member from the anvil via the tool bit, using the output signal of the sensor. The rotary impact tool according to any one of claims 1 to 5.

7. The sensor a magnetostrictive film formed on at least a portion of the outer peripheral surface of the anvil; a coil disposed so as to surround the magnetostrictive film, the circuit board further includes an amplifier circuit that amplifies a voltage signal from the coil and provides the amplified voltage signal to the processing circuit; The rotary impact tool according to claim 6.

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