power tools

Abstract

To prevent a control circuit board from being damaged by an impact caused when an electric power tool is fallen.SOLUTION: In an electric power tool having a split type housing 2 in which a battery attachment part is formed at a tip of a handle part, a control circuit board 61 is housed in a housing case 65 and is held in a sandwiching manner by the two fraction housing 2. A beam part (a first support part) 40 which supports a control circuit part 60 from below is located below the substrate case 65. Further, a column part (a second support part) 65e extending upward from the bottom surface of the substrate case 65 is provided immediately below a specific portion 34 where an outer edge of an opening 45 and a divided surface intersect. The specific portion 34, the column part 65e, and the beam part 40 are disposed so as to be arranged in a vertical direction. Even if downward deformation is caused in the specific portion 34 by an impact when the electric power tool is fallen on a floor etc., the support parts 65e and the beam part 40 effectively receive the impact and thus damage of the control circuit board 61 can be prevented.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a power tool that is provided with measures to protect it from shocks caused by dropping or the like. [Background technology]

[0002] Cordless handheld power tools, which are powered by electrical energy stored in a battery, are widely used. In power tools that use a motor to rotate a tool tip such as a drill or a screwdriver to perform a required task, the motor is driven by a battery, as disclosed in, for example, Patent Document 1. The rotational force of the motor is converted into rotational motion of an output shaft via a power transmission mechanism, thereby rotating the tool tip. Such a power tool is disclosed, for example, in Patent Document 1.

[0003] In a power tool such as that described in Patent Document 1, a handle portion is formed extending from approximately the center of the body portion in a direction substantially perpendicular to the axial direction, and a battery attachment portion is provided at the tip of the handle portion, at a position away from the body portion (the end portion opposite the body portion). The battery attachment portion extends in a direction intersecting the axis of the handle portion, and a battery pack is attached to its lower side. A control circuit board for controlling the motor is provided inside the battery attachment portion. In addition, a switch panel is provided on the upper surface of the battery attachment portion. The switch panel is provided with soft-touch buttons for setting the motor's rotation speed and impact strength, a switch for turning on and off a lighting device provided near the output shaft, and the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-124725 Summary of the Invention [Problem to be solved by the invention]

[0005] With handheld power tools, carelessness can lead to accidental dropping of the power tool to the ground. For this reason, power tool manufacturers have implemented impact protection measures to minimize damage even if dropped. Various parts of the power tool are subject to impact when dropped. In the process of developing impact protection measures, the inventors discovered that, for example, in the case of a battery-powered power tool, if a power tool 1 with the battery facing downwards is dropped from a position higher than the normal working position, the area near the base of the handle and the battery attachment section may deform, potentially damaging the control circuit board located below. They also discovered that the amount of deformation near the connection between the handle and the battery attachment section is particularly large when an opening is provided near the top surface of the battery attachment section to accommodate a switch panel. Furthermore, even power tools that are not cordless but use commercial power, such as those powered by commercial power, may have a housing for the circuit board at the end of the handle. Deformation of the housing section may damage the circuit board if the power tool is dropped. In particular, when the storage section or battery mounting section is provided so as to protrude radially beyond the handle, and the circuit board is arranged across the protruding section from the longitudinal extension of the handle, there is a high risk that the circuit board will be damaged due to deformation of the storage section.

[0006] The present invention has been made in consideration of the above background, and its purpose is to provide an electric power tool that significantly reduces the risk of damage to the circuit board due to deformation of the housing when the electric power tool is dropped on the ground or the like. Another object of the present invention is to provide a power tool in which a circuit board held by a split housing is protected from localized deformation of the housing when the housing is dropped or impacted. Another object of the present invention is to provide an electric power tool in which the structure of the board case that houses the circuit board is modified to effectively protect the circuit board housed in the board case from damage in the event of a drop impact. [Means for solving the problem]

[0007] Representative features of the invention disclosed in this application are as follows. According to one feature of the present invention, there is provided an electric power tool comprising: a motor, a body portion for accommodating the motor, a housing having a dividing surface in the left-right direction that is the dividing direction, and a handle portion extending downward from the body portion to be gripped by an operator; a control circuit portion having a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and resin filled inside the board case so as to immerse the upper and lower surfaces of the control circuit board; an accommodating portion provided below the handle portion and having a protruding portion that protrudes forward and left-right from the handle portion, and accommodating the control circuit portion; an input / output operating portion provided on the upper surface of the protruding portion so as to extend left-right on the upper surface of the protruding portion and for allowing the operator to perform input operations; and an opening provided on the upper surface of the protruding portion so as to extend left-right and be divided by the dividing surface, the opening having an outer edge that holds the input / output operating portion so as to sandwich it in the dividing direction, wherein the outer edge has a portion where the outer edge on the handle portion side of the opening intersects with the dividing surface, and the intersecting portion is located above the control circuit portion and faces the control circuit portion; and a first support portion is provided inside the accommodating portion at a position below the control circuit portion in the up-down direction to support the control circuit portion from below. A second support portion extending upward from the bottom surface of the board case is disposed directly below the intersecting portion, and the intersecting portion, the first support portion, and the second support portion are disposed so as to be aligned in the vertical direction.

[0008] According to another feature of the present invention, the left and right edges of the board are held in a non-contact state by the housing. A step or support is provided in front of the housing to support the underside of the front edge of the board. A gap is provided between the board and the screw when viewed in the radial direction of the screw. A switch panel that forms the operating surface of the switch element is disposed above the board, and a fixing tab extending from the switch panel is held by the screw. An opening is formed in the radially protruding portion of the handle at a position facing the board, and the support suppresses deformation of the edge of the opening.

[0009] According to another aspect of the present invention, there is provided a power tool having a housing, a motor housed in the housing, a power transmission mechanism for transmitting the rotational force of the motor to a tool bit, and a control unit for controlling the rotation of the motor, the housing having a handle portion and a battery mounting portion formed at the tip thereof, the battery mounting portion having an extension portion extending in a direction intersecting the axial direction of the handle portion, the housing being sandwiched between the left and right sides, an opening formed in the extension portion at a plane intersecting the axial direction so as to straddle the sandwiching dividing plane, and a battery being attached to the side of the extension portion opposite the handle portion. In this power tool, a control circuit board mounting the control unit is provided between the battery and the handle portion inside the extension portion, the control circuit board is sandwiched and held by the two-piece housing, and a support portion is provided for directly or indirectly holding the control circuit board in a direction perpendicular to the dividing plane. The support portion is located at a position overlapping a portion of the periphery of the opening when viewed in the longitudinal direction (direction B1) of the handle portion.

[0010] According to yet another feature of the present invention, the control circuit board is housed in a container-shaped board case having a two-piece housing with a convex portion formed on the edge in the direction of division, and is held by clamping the convex portion of the board case between recesses formed on the inner wall of the housing. The support portion is formed to contact the board case and can be formed as a linear beam portion extending in the direction of division on the underside of the board case. The beam portion is preferably formed integrally with the housing, and a portion of the periphery of the opening and a portion of the beam portion are positioned to overlap in the longitudinal direction (direction B1) of the handle portion. Here, it is preferable that the length of the beam portion is formed longer than the width of the control circuit board. Furthermore, the board case may be formed with a pillar portion extending from the bottom surface to the upper opening, and a through-hole may be formed in the control circuit board to allow the pillar portion to pass through.

[0011] According to yet another feature of the present invention, in an electric power tool in which an opening is formed in an extension of a battery mounting portion of a housing so as to straddle a dividing plane, the control circuit board is housed in a container-shaped circuit board case having a convex portion formed on an edge in the dividing direction, the circuit board case having an upper opening larger than the outer edge of the upper surface of the control circuit board, and a beam member is disposed so as to straddle the upper opening of the circuit board case. The beam member is formed of an elongated metal plate or metal rod. In addition, a battery terminal portion is formed between the control circuit board and the battery, holding a group of device-side terminals for connection to the battery terminal portion, and the beam member is formed by the convex portion formed on the battery terminal portion, and a support portion is provided at a position overlapping with a part of the peripheral edge of the opening as viewed in the longitudinal direction (direction B1) of the handle portion.

[0012] According to yet another feature of the present invention, the device includes a body portion that houses a motor, a handle portion that is gripped by an operator, and a housing portion that is provided at the end of the handle portion and protrudes radially from the handle portion and houses a circuit board on which electronic components are mounted. The circuit board is housed in the housing portion from a position on the extension of the handle portion to the protruding portion of the housing portion. An opening is formed in the protruding portion of the housing portion at a position facing the circuit board, and a support portion is provided in the housing portion to suppress deformation of the edge of the opening. The circuit board is housed in the housing portion so as to face the edge, and the support portion is integrally formed with the housing portion to support the circuit board on the side opposite the edge of the circuit board. The circuit board has a first surface (upper opening surface) that faces the edge and a second surface (bottom surface) that is opposite the edge of the first surface, and is housed in the housing portion while being housed in a circuit board case. The support portion is provided on the circuit board case so as to extend from the second surface side through the circuit board toward the first surface of the circuit board, or so as to extend from the second surface side toward the opposite side of the circuit board and contact a portion fixed to the housing portion. The substrate may be accommodated in the accommodation portion so as to face the edge portion, and a separate support portion may be provided between the edge portion and the substrate. The accommodation portion may also have a battery mounting portion for mounting a battery and a terminal holder provided with a tool-side terminal that connects to a battery-side terminal of the battery, the terminal holder being provided on the opposite side of the substrate from the edge portion so as to face the substrate, and the support portion being provided on the terminal holder.

[0013] According to another feature of the present invention, the tool comprises a body that houses a motor, a handle that is gripped by an operator, and a housing portion that is provided at the end of the handle and protrudes radially from the handle to house a circuit board on which electronic components are mounted, the circuit board being housed in the housing portion from a position on the extension of the handle to the protruding portion of the housing portion, and an opening is formed in the protruding portion of the housing portion at a position opposite the circuit board. A sufficient gap is provided between the edge of the opening and the circuit board so that the edge will not come into contact with the circuit board even if it is deformed by the impact of being dropped. [Effects of the Invention]

[0014] According to the present invention, even if a specific portion of the housing is deformed when an impact such as a drop is applied to the housing of a power tool, causing a compressive force due to the deformation to act on the circuit board, the support portion disposed below the circuit board suppresses the deformation of the circuit board, thereby effectively preventing failure of the power tool due to damage to the circuit board. Furthermore, the support portion can be manufactured integrally with the housing as a beam portion extending perpendicular to the housing dividing surface, thereby increasing strength and suppressing increases in manufacturing costs. Furthermore, the other support portion is formed of a metal plate connecting two sides of the circuit board case perpendicular to the dividing surface, so the present invention can be easily implemented by simply changing the circuit board case. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a right side view of a power tool 1 according to an embodiment of the present invention. [Figure 2] 1 is a vertical cross-sectional view showing the internal structure of a power tool 1 according to an embodiment of the present invention. [Figure 3] (A) is a partially enlarged cross-sectional view of the battery mounting portion 2c in Figure 2, (B) is a diagram for explaining the positional relationship between the position of the maximum deformation point of the housing as viewed in the front-to-back direction and the support portion (when stationary), and (C) is a diagram for explaining the positional relationship between the position of the maximum deformation point of the housing as viewed in the front-to-back direction and the support portion (when an impact occurs). [Figure 4]4A and 4B are cross-sectional views of the AA portion of FIG. 3, where (B) is a diagram for explaining the positional relationship (when stationary) between the position of the maximum deformation point of the housing as viewed from the left and right and the beam member 40 serving as the support portion, and (C) is a diagram for explaining the positional relationship (when an impact occurs) between the position of the maximum deformation point of the housing as viewed from the left and right and the support portion. [Figure 5] FIG. 4 is a perspective cross-sectional view taken along the line BB in FIG. 3. [Figure 6] 3(A) is a partially enlarged cross-sectional view of the battery attachment portion 2c, which is the same as FIG. 3(A), showing a state of deformation when an impact is applied by dropping the battery attachment portion 2c in an upright position. [Figure 7] FIG. 7 is a cross-sectional view of the CC portion of FIG. 6. [Figure 8] 10 is a top view showing the outer shape of the extension portion of the battery mounting portion 2c, and is a diagram showing the detailed shape of the switch panel 46. FIG. [Figure 9] FIG. 10 is a partially enlarged cross-sectional view of a battery mounting portion according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a partially enlarged cross-sectional view of a battery attachment portion according to a third embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view of the DD portion of FIG. [Figure 12] FIG. 10 is a partially enlarged cross-sectional view of a battery attachment portion of a housing 2A according to a fourth embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional view of the EE portion of FIG. [Figure 14] FIG. 10 is a partially enlarged cross-sectional view of a battery attachment portion according to a fifth embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view of the FF portion in FIG. [Figure 16] FIG. 10 is a partially enlarged cross-sectional view of a battery attachment portion according to a sixth embodiment of the present invention. [Figure 17] FIG. 17 is a cross-sectional view of the GG portion of FIG. [Figure 18](A) is a partially enlarged cross-sectional view of the battery mounting portion 202c of a conventional impact tool, (B) is a diagram showing the position (when stationary) of the maximum deformation point (specific portion 234) of the housing 202 when viewed in the front-to-back direction, and (C) is a diagram showing the positional relationship between the position of the maximum deformation point of the housing 202 when viewed in the front-to-back direction and the support portion (when an impact occurs). [Figure 19] 18A and 18B are cross-sectional views of the HH portion of the housing 202, where (B) shows the position of the maximum deformation point (specific portion 234) of the housing 202 as viewed from the left and right, and the positional relationship between the ribs 238a and 238b (when stationary), and (C) shows the position of the maximum deformation point of the housing as viewed from the left and right, and the positional relationship between the ribs 238a and 238b (when an impact occurs). [Figure 20] FIG. 11 is a perspective view of a control circuit unit 130 of a power tool 101 according to a seventh embodiment of the present invention. [Figure 21] 21 is an exploded perspective view of the control circuit section 130 of FIG. 20. FIG. [Figure 22] 21 is a perspective view showing a state in which the control circuit section 130 of FIG. 20 is attached to the housing 102. FIG. [Figure 23] FIG. 11 is a partially enlarged cross-sectional view of a battery attachment portion 102c of a power tool 101 according to a seventh embodiment. [Figure 24] 10A and 10B are diagrams of a board case 135 of a seventh embodiment, in which (A) is a top view, (B) is a cross-sectional view of the KK portion of (A), and (C) is a cross-sectional view of the LL portion of (A). [Figure 25] FIG. 24 is a partial enlarged view of part M in FIG. 23. [Figure 26] 10A is a top view of the control circuit section 130 of the seventh embodiment, and FIG. 10B is a top view of the conventional control circuit section 230. FIG. [Figure 27] FIG. 13 is a partially enlarged view of the vicinity of a support portion of a control circuit board 131 according to a modified example of the seventh embodiment. [Figure 28] (A) is a diagram showing the position of stress transmitted from the maximum deformation point of the housing 102 in the seventh embodiment to the substrate case 135, and (B) is a diagram showing the position of stress transmitted from the maximum deformation point of the conventional housing 202 to the substrate case 135. [Figure 29]10A and 10B are cross-sectional views showing the control circuit section 130 of the power tool according to the eighth embodiment of the present invention, where (A) is a vertical cross-sectional view passing through the dividing plane of the housing 102, and (B) is a longitudinal cross-sectional view perpendicular to (A). DETAILED DESCRIPTION OF THE INVENTION [Example]

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same parts are given the same reference numerals, and repeated explanations will be omitted. In addition, in this specification, the front-rear and up-down directions will be described as the directions shown in the drawings.

[0017] 1 is a side view showing the appearance of a power tool 1 according to an embodiment of the present invention. The power tool 1 is powered by a rechargeable battery pack 300 and driven by a motor to apply rotational force and impact force to an output shaft 10. The rotational force is intermittently transmitted to a tool tip (not shown), such as a driver bit, that is attached to a mounting hole 10a and held by a mounting mechanism 11, thereby performing tasks such as screw tightening and bolt tightening. The housing 2 of the power tool 1 is composed of three parts: a substantially cylindrical body 2a for accommodating the motor and power transmission mechanism; a handle 2b that extends from approximately the center of the body 2a in a direction substantially perpendicular (downward) to the axis A1 and is adapted to be held by an operator with one hand; and a battery attachment portion 2c that is provided at the lower end of the handle 2b opposite the body 2a (the end opposite the body). The body portion 2a of the housing 2 is integrally molded from a synthetic resin material along with the handle portion 2b and the battery attachment portion 2c. The body portion 2a is divided into two halves, left and right, along a vertical plane passing through the rotation shaft 4 of the motor 3. During assembly, the motor, reduction gear, impact mechanism, etc. are installed in one of the housings 2 (e.g., the left housing), and then the other housing 2 (e.g., the right housing) is placed on top of the housing and fastened with multiple screws 29a-29h into the screw bosses of the housings. A trigger lever 7a is disposed at the top of the handle portion 2b so as to protrude forward. A forward / reverse switching lever 8 is provided behind the trigger lever 7a for switching the rotation direction of the output shaft 10 between forward and reverse. The battery attachment portion 2c is formed to extend horizontally at the lower end (opposite the body end) of the handle portion 2b opposite the body portion 2a. A battery 300, a secondary battery such as a lithium-ion battery, is removably attached to the battery attachment portion 2c. When removing the battery 300 from the state shown in FIG. 1, the battery 300 is moved forward relative to the power tool body while pressing the latch buttons 301 on both sides.

[0018] A slit-shaped air intake 17b is formed near the rear end of the body 2a of the housing 2, and a slit-shaped air exhaust port 17c for exhausting air is formed in front of it near the outer periphery of the rotor fan 15 (described later in FIG. 2). A cup-shaped hammer case 5 is provided in the front of the body 2a of the housing 2, and has a through-hole 5a at its tip through which the output shaft 10 passes. An LED-based lighting device 9 is provided below the front end of the hammer case 5.

[0019] The battery mounting section 2c is provided with a rail mechanism and a group of connection terminals for mounting the battery 300, and also houses a control circuit board (described later in FIG. 2) therein. The width of the battery mounting section 2c is approximately the same as the top surface of the battery 300. A first switch panel 46 is provided on the top surface of the battery mounting section 2c, in a portion forward of the lower end of the handle section 2b. The first switch panel 46 is equipped with a light switch for turning on the illumination device 9 for illuminating the object to be fastened with the tool bit, a battery remaining capacity indicator switch and battery remaining capacity indicator lamp for displaying the remaining capacity of the battery 300, and a strength indicator lamp for displaying the striking strength. A second switch panel (not shown) is also provided on the left side surface of the battery mounting section 2c, and is equipped with a strength switch (not shown) for adjusting the striking strength (tightening strength).

[0020] FIG. 2 is a longitudinal cross-sectional view showing the internal structure of the power tool 1 of this embodiment. The motor 3 is housed in a cylindrical body portion 2a of the housing 2, which is generally T-shaped in side view. The motor 3 is a brushless DC (direct current) motor with four poles and six slots. The motor 3 includes a rotor 3a equipped with a permanent magnet and a stator 3b equipped with a multi-phase armature winding (stator winding), such as a three-phase winding. The motor 3 operates by switching DC voltage supplied from a battery or the like using multiple semiconductor switching elements 14, using the output of a position detection element 13, which is composed of three Hall ICs that detect the magnetic force of the permanent magnet of the rotor 3a to detect the rotor position. The rotating shaft 4 of the motor 3 is positioned concentrically with the axis A1 of the cylindrical body portion 2a and is journaled to the housing 2 by two bearings 16a, 16b at the front and rear. A substantially annular inverter circuit board 12 is disposed behind the stator 3b, on which are mounted three position detection elements 13, six semiconductor switching elements 14, and other components. The inverter circuit board 12 is a substantially annular double-sided board with a diameter roughly equal to the outer diameter of the motor 3. Six semiconductor switching elements 14 are provided to form an inverter circuit, which switches the power supply to the stator windings of each phase. FETs (field-effect transistors) and IGBTs (insulated gate bipolar transistors) are used as the semiconductor switching elements 14. The inverter circuit is controlled by a microcomputer, which sets the power supply timing for the armature windings of each phase based on the position detection results of the rotor 3a by the position detection elements 13, facilitating advanced rotation control.

[0021] The hammer case 5 accommodates the reduction gear mechanism 20 and the impact mechanism 21 inside, and is provided on the front side of the body portion 2a of the housing 2. The hammer case 5 is manufactured as a single piece of metal, and a through hole 5a is formed in the front part, which corresponds to the bottom of the cup shape, for passing the output shaft 10 through. An attachment mechanism 11 is provided at the tip of the output shaft 10 that protrudes outside the hammer case 5, for attaching or detaching a tool tip (not shown).

[0022] A rotor fan 15 is attached coaxially with the rotary shaft 4 between the rotor 3a and the bearing 16a. The rotor fan 15 is integrally molded, for example, from a plastic mold, and is a so-called centrifugal fan that draws air from the inner circumferential side at the rear and discharges it radially outward at the front. The airflow generated by the rotor fan 15 is taken into the body portion 2a through air intakes 17a and air intakes 17b (see FIG. 1) formed in the housing portion around the inverter circuit board 12, flows forward mainly passing between the rotor 3a and the stator 3b, and is discharged by the rotor fan 15 to the outside of the housing 2 through slit-shaped air discharge ports 17c (see FIG. 1), which will be described later, formed in the housing portion around the rotor fan 15.

[0023] The rotor 3a forms a magnetic path formed by permanent magnets. The stator 3b is manufactured with a laminated structure of thin, annular iron plates, and six teeth (not shown) are formed on the inner periphery, with enameled wire wound around each tooth to form a coil. In this embodiment, the coil is star-connected with three phases: U, V, and W.

[0024] The handle portion 2b of the housing 2 is the portion to be gripped by the operator, and is substantially cylindrical along the axis B1, shaped to be suitable for gripping with one hand. The trigger switch 7 is disposed inside the handle portion 2b, and various wiring such as lead wires from the control circuit portion 30 to the body portion 2a is housed therein. Since heavy objects such as the motor 3 and the power transmission mechanism (the reduction mechanism 20 and the impact mechanism 21) are disposed above the handle portion 2b, the connection portion between the handle portion 2b and the body portion 2a is configured to have sufficient strength. Similarly, since a heavy object such as the battery 300 is disposed below the handle portion 2b, the connection portion between the handle portion 2b and the battery attachment portion 2c is configured to have sufficient strength. In particular, the bases 43a to 43d of the connection portions are reinforced.

[0025] The battery attachment portion 2c of the housing 2 has portions that protrude forward and left / right from a position on the extension of the handle portion 2b. Inside the battery attachment portion 2c, a control circuit unit 30 is housed. The control circuit unit 30 includes a control circuit board 31 (described later in FIG. 3) that controls the speed of the motor 3 when the trigger lever 7a is pulled. The control circuit unit 30 is electrically connected to the battery 300 and the trigger switch 7 via multiple lead wires. The control circuit board 31 is also provided with a connector (not shown) for connecting the lead wires (not shown) to the control circuit board 31. The control circuit board 31 is further electrically connected to the inverter circuit board 12 via multiple lead wires. Near the control circuit board 31, on the top surface of the battery attachment portion 2c, is provided an input / output operation unit for input operations and display operations using LEDs or the like. Here, a separate switch panel 46 is provided on the housing 2 as the input / output operation unit. This panel includes a switch for checking the remaining charge of the battery 300, an LED display for displaying the remaining charge, and a switch for turning on the lighting device 9 (details will be described later in FIG. 8). The switch panel 46 is fixed firmly or loosely to the control circuit unit 30 side and is held by being sandwiched in the dividing direction (left and right direction) by an opening 45 arranged so as to be divided by the dividing surface of the housing 2. The opening 45 is provided in a protruding portion of the battery mounting portion 2c. The battery mounting portion 2c corresponds to a housing portion that houses a circuit board.

[0026] The impact mechanism 21 is provided on the output side of the planetary gear reduction mechanism 20 and includes a spindle 22 and a hammer 24. Its rear end is rotatably supported by bearing 18b and its front end by bearing 18a. The reduction mechanism 20 and impact mechanism 21 form a power transmission mechanism for driving the tool bit with the motor 3. When the trigger lever 7a is pulled to start the motor 3, the motor 3 begins to rotate in the direction set by the forward / reverse switching lever 8. The rotational force is reduced by the reduction mechanism 20 and transmitted to the spindle 22, which then rotates at a predetermined speed. The spindle 22 and hammer 24 are connected by a cam mechanism, which is composed of a V-shaped spindle cam groove 23 formed on the outer circumferential surface of the spindle 22, a hammer cam groove 25 formed on the inner circumferential surface of the hammer 24, and a steel ball 26 that engages with the spindle cam grooves 23, 25. The hammer 24 is constantly biased forward by a hammer spring 27, and when stationary, is positioned with a gap between it and the end face of the anvil 28 due to the engagement of the steel ball 26 with the spindle cam grooves 23 and 25. Convex portions (not shown) are formed symmetrically at two locations on the opposing rotation planes of the hammer 24 and the anvil 28.

[0027] When the spindle 22 is driven to rotate, the rotation is transmitted to the hammer 24 via the cam mechanism, and the protrusion of the hammer 24 engages with the protrusion of the anvil 28 before the hammer 24 has rotated half a turn, causing the anvil 28 to rotate, but when a relative rotation occurs between the spindle 22 and the hammer 24 due to the reaction force of the engagement, the hammer 24 begins to retreat toward the motor 3 while compressing the hammer spring 27 along the spindle cam groove 23 of the cam mechanism. Then, when the retraction of the hammer 24 causes the protrusion of the hammer 24 to overcome the protrusion of the anvil 28 and the engagement therebetween is released, the hammer 24 is rapidly accelerated in the rotational direction and forward by the rotational force of the spindle 22, the elastic energy stored in the hammer spring 27, and the action of the cam mechanism, and the hammer 24 moves forward by the biasing force of the hammer spring 27, and the protrusion reengages with the protrusion of the anvil 28, and the two begin to rotate together. At this time, a strong rotational impact force is applied to the anvil 28, which is transmitted to the screw via a tool bit (not shown) attached to the mounting hole 10a of the anvil 28. Thereafter, the same operation is repeated, and the rotational impact force is intermittently and repeatedly transmitted from the tool bit to the screw, until the screw is screwed into a member (not shown) to be fastened, such as wood.

[0028] 3A is a partially enlarged cross-sectional view of the battery mounting portion 2c in FIG. 2. The battery mounting portion 2c constitutes a mounting portion for mounting the battery 300, holds a terminal holder 50 on which tool-side terminals for connection to battery 300-side terminals (battery-side terminals), and also functions as a housing for accommodating the control circuit unit 30. The control circuit unit 30 is configured such that a control circuit board 31, on which a microcomputer and other electronic elements, connectors, and other electronic components (not shown) are mounted, is housed inside a board case 35, which is a dish-shaped container with an opening at the top. The board case 35 is filled with resin 33. The control circuit board 31 has a first surface (top surface) facing the opening 45 and a second surface (bottom surface) on the opposite side of the first surface from the opening 45. The resin 33 is filled in a liquid state inside the board case 35 and hardened; for example, a curable resin such as urethane is used. Here, resin 33 is poured up to the top opening of board case 35, filling it, and then curing. This causes the top surface (liquid level) of resin 33 to be approximately flush with the top of board case 35, completely immersing the portion of control circuit board 31 located inside board case 35. The curable resin used here should preferably have enough elasticity to allow for a certain degree of deformation when subjected to a load from an external pressure. However, any type of curable resin may be used. It may not only be one that is elastic after curing, but also one that hardens after curing and has little or no elasticity. Board case 35 is formed by integral molding of a synthetic resin such as plastic. Small protrusions 35a and 35b protruding in the left-right direction are formed on parts of the outer surface of board case 35, on the edges in the direction in which housing 2 is divided (left-right direction). Furthermore, protrusion 35c protruding forward from the front edge is formed. Protrusion 35c has a sufficient length that continues in the left-right direction. Additionally, a recess 35e is formed on the bottom surface on the rear side, and vertical movement is restricted by ribs 39b extending parallel to the vertical direction and formed on the inner side wall portion of the housing 2. The board case 35 is sandwiched between the left and right split housing 2 so that these protrusions 35a to 35c fit into recesses 38c and the like formed on the inner side wall portion of the housing 2, and is thereby stably held in the housing 2.The terminal holder 50 is disposed on the opposite side (lower side) of the control circuit board 31 from the opening 45 side, and is provided so as to face the control circuit board 31.

[0029] A soft layer 6 (6c) is formed on the surface of the housing 2 to cushion impacts during collisions, improve the feel when gripped by an operator, and provide a non-slip surface. The soft layer 6 is, for example, elastomer, and is formed into a two-layer structure by covering the entire surface during injection molding of the synthetic resin housing 2. A beam member 40 extending in the left-right direction and having a flat top surface is provided on the underside of the circuit board case 35. The beam member 40 is provided so as to contact the bottom surface 35d of the circuit board case 35, and is located slightly forward of the center of the bottom surface in the front-to-rear direction. The beam member 40 has a hollow rectangular prism shape and extends from the right side surface of the battery mounting portion 2c of the housing 2 to the left side surface. The beam member 40 is also made of synthetic resin, like the housing 2, and is molded integrally with the housing 2. A terminal holder 50 is provided on the rear side of the beam member 40, below and facing the control circuit unit 30 in the vertical direction. Terminal holder 50 is a component for holding a plurality of connection terminals (tool-side terminals, not shown) for contacting connection terminals (battery-side terminals, not shown) of battery 300 (see FIG. 2), and has a recess 51a formed on the front edge and a recess 51b formed on the rear edge, which are fitted with protrusions formed on housing 2, thereby allowing attachment to the underside of battery attachment section 2c. Battery attachment section 2c further has rail groove 52-2 and rail section 53-2, and a latch groove 54-2 formed near the front end of rail section 53-2.

[0030] FIG. 3(B) is a model diagram of the load position and deformation degree of the control circuit unit 30, showing the position of the maximum deformation point of the housing as viewed in the front-rear direction and the positional relationship (when stationary) with the beam member 40 serving as the support member. The shape of the control circuit unit 30 is simplified and depicted as a rectangle. Here, reference numeral 34 indicates the front-rear direction position of a specific portion 34 that comes into contact with the control circuit unit 30 (particularly the upper surface of the resin 33) when the power tool 1 is dropped onto a floor or the like in an upright position with the battery 300 facing downwards. The specific portion 34 corresponds to the vicinity of the intersection of the outer edge of the opening 45 and the dividing surface of the housing 2, and corresponds to the vicinity of a part of the edge of the opening 45, as indicated by the arrow in FIG. 3(A). In this example, when no impact is applied, the deforming portion 34 of the housing 2 is located at a position separated from the control circuit unit 30 as shown in FIG. 3(B). However, when the power tool 1 is dropped upright and hits the floor, a strong weight 36A is applied to the portion 34 via the handle portion 2b, causing the portion 34 to move downward (deform) and hit the control circuit unit 30. However, in this embodiment, the beam member 40 extending laterally is located on the opposite side of the circuit board case 35 from the direction in which the weight 36A is applied. Therefore, the force of the control circuit unit 30 attempting to deform is supported from below by the beam member 40 as indicated by the force of arrow 41. The portion 34 is located above the control circuit unit 30 and faces the control circuit unit 30 (which holds the control circuit board 31 via the resin 33). The opening 45 is also located above the control circuit unit 30 and faces the control circuit unit 30.

[0031] For comparison, the shape of the housing 202 of a conventional impact tool will be described with reference to FIG. 18. FIG. 18(A) is a partially enlarged cross-sectional view of the battery attachment portion 202c of the conventional impact tool. The control circuit unit 30 is the same component as that shown in FIG. 3. The shape of the housing 202 is the same as that of the housing 2 shown in FIG. 3, except that the beam member 40 is not formed. The housing 202 is also the same as the housing 2 shown in FIG. 3 in that an opening 45 is provided above the front side of the control circuit unit 30. The board case 35 has a protrusion 35c on the front side, which fits into a recess 238c formed in the housing 202. Ribs 239a and 239b (however, 239a is not visible in the figure) extending parallel to one another in the vertical direction are formed on the inner sidewall of the housing 2 near the rear side of the board case 35 so as to abut the left and right edges. FIG. 18(B) shows the position of the maximum deformation point (specific portion 234) of housing 202 when stationary, as viewed from the front-rear direction, and FIG. 18(C) shows the positional relationship between the position of the maximum deformation point of housing 202 and the support portion when an impact occurs. When viewed from the front-rear direction, control circuit unit 30 is held by front recess 238c and rear ribs 239a and 239b. Specific portion 234 is located between front recess 238c and rear ribs 239a and 239b. If a downward force in the direction of arrow 236 acts on specific portion 234 due to, for example, the impact tool being dropped, specific portion 234 deforms and comes into contact with control circuit unit 30, causing control circuit unit 30 to bend downward with recess 238c and rear ribs 239a and 239b as fulcrums. In response to downward force 236, upward forces 240a and 240b are applied from ribs 239a and 239b. Returning to Figure 3, as is clear from a comparison of Figure 3(C) and Figure 8(C), in this embodiment, the beam member 40 is located at a position that coincides vertically with the maximum deformation point (specific portion 234) of the housing 202, thereby effectively suppressing deformation of the control circuit section 30.

[0032] FIG. 4A is a cross-sectional view taken along line AA in FIG. 3 and illustrates the shape of the housing 2 of this embodiment. The container-shaped circuit board case 35 has left and right walls, and two protrusions 35a and 35b are formed at the top so as to protrude horizontally. The circuit board case 35 is open on the side (first side) facing a portion 34 (described later) of the control circuit board 31, and covers the side (second side) opposite the first side. Note that because the AA cross section in FIG. 3A is not completely flat, it appears that the lower surfaces of the protrusions 35a and 35b do not abut against the inner wall surface of the battery mounting portion 2c of the housing 2. However, as can be seen by comparing the position of line AA in FIG. 3A, the lower surfaces of the protrusions 35a and 35b actually abut against ribs formed on the inner wall surface of the battery mounting portion 2c. The size of the protrusions 35a, 35b in the front-to-rear direction is not comparable to the length of the board case 35, and as shown by the dotted lines in Fig. 3(A), the protrusions 35a, 35b are formed only on a portion of the front side. This is because the control circuit board 31 is lighter in weight than the other components (motor 3, power transmission mechanism, battery 300), and does not require much strength unless it is subjected to an excessive impact due to a fall. Here, the beam member 40 is formed so as to be located at one position that coincides with the deformable portion 34 when viewed in the first direction (front-to-rear direction) of the control circuit unit 30 (or control circuit board 31).

[0033] For comparison, the shape of the housing 202 of a conventional impact tool is also described using FIG. 19 . FIG. 19 is a cross-sectional view of the HH portion of FIG. 18 . Because the beam member 40 is not formed on the underside of the circuit board case 35, the housing 202 is provided with ribs 238a and 238b for holding the protrusions 35a and 35b. Meanwhile, a gap is formed below the bottom surface 35d of the circuit board case 35. FIG. 19(B) shows the position of the maximum deformation point (specific portion 234) of the housing 202 in the left-right direction and the relative positions of the ribs 238a and 238b that hold the protrusions 35a and 35b (at rest). FIG. 19(C) shows the position of the maximum deformation point of the housing in the left-right direction and the relative positions of the ribs 238a and 238b (when an impact occurs). As can be seen from this figure, when a strong force is applied to the specific portion 234 in the direction indicated by arrow 236, the control circuit unit 30 bends downward. At this time, the portions receiving the force of arrow 236 are the left and right ends, and the points of action thereof are 141a and 141b.

[0034] FIG. 4B shows the positional relationship (when stationary) between the position of the maximum deformation point of the housing 2 and the beam member 40 serving as a support member, as viewed from the left to right. The beam member 40 is composed of a right beam member 40-1 molded integrally with the right portion of the housing 2 and a left beam member 40-2 molded integrally with the left portion of the housing 2. The contact portions of the right beam member 40-1 and the left beam member 40-2 are formed concave on one side and convex on the other, so that the concave and convex portions fit together when joined. The beam members 40-1 and 40-2 contact the bottom surface 35d of the circuit board case 35 so as to be continuous in the left-right direction. This state is shown in FIG. 4B. When the power tool is stationary (not subjected to a drop impact), the specific deformable portion 34 is out of contact with the control circuit unit 30 with a predetermined gap. When the power tool 1 is dropped upright and hits the floor, a strong load 36A applied through the handle portion 2b causes a specific portion 34 to move downward and come into contact with the control circuit unit 30, as shown in FIG. 4(C). However, in this embodiment, the beam members 40 extending in the left-right direction are located on the opposite side of the circuit board case 35 on the extension line of the position where the load 36A is applied. Therefore, the beam members 40 (40-1 and 40-2) support the control circuit unit 30 from below in the direction of the force indicated by the arrow 41A. Here, the beam members 40 (40-1 and 40-2) are positioned across the entire left and right sides of the control circuit unit 30 (or the control circuit board 31), including the deforming portion 34, when viewed in the second direction (left-right direction) of the control circuit unit 30 (or the control circuit board 31). Providing the beam members 40 in this manner effectively prevents the control circuit board 31 of the control circuit unit 30 from being deformed due to an excessive load applied thereto. In particular, when comparing the degree of bending of the control circuit section 30 in Figure 4(C) with the degree of bending of the control circuit section 30 in Figure 19(C), it will be understood that the structure shown in Figure 4 causes significantly less bending to the control circuit board 31.

[0035] FIG. 5 is a perspective cross-sectional view taken along the line BB in FIG. 3. In this cross-sectional view, no protrusions are formed on either the left or right side of the board case 35. The actual control circuit board 31 is equipped with a microcomputer and other electronic components, but these are not shown. Walls 37 support the board case 35 on both the left and right sides to prevent it from rattling in the left-right direction. Beam members 40 (40-1, 40-2) are provided below the board case 35. The beam members 40 are cylindrically shaped, with a hollow longitudinal axis and cross-sectional shape, but may be solid beam members instead. The right beam member 40-1 is molded integrally with the right battery mounting portion 2c-1, and the left beam member 40-2 is molded integrally with the left battery mounting portion 2c-1, providing sufficient strength. The upper surface of the battery 300 is located below the beam members 40, and rail grooves 52-1, 52-2 are formed on both the left and right sides. Rail portions 53-1 and 53-2 that protrude inward are formed below the rail grooves 52-1 and 52-2, respectively. Latch grooves 54-1 and 54-2 for engaging with latch pawls are formed at the tip ends of the rail portions 53-1 and 53-2.

[0036] An opening 45 is formed on the upper surface of the battery mounting portion 2c so as to intersect with the joint surface between the battery mounting portions 2c-1 and 2c-2. The opening 45 is formed to accommodate a switch panel 46 (see FIG. 1) and is located near the front of the base of the handle portion 2b (2b-1, 2b-2) of the housing 2. If the opening 45 is located near the base 43d of the handle portion 2b (2b-1, 2b-2) and the battery mounting portion 2c (2c-1, 2c-2), the strength of the portion near the base 43d of the opening 45 (specific portion 34) is reduced compared to other portions. When the power tool 1 is dropped upright and hits the floor, the battery 300 often hits the floor first. In this case, the weight of the dropped heavy object, such as the motor 3 or the power transmission mechanism, is applied to the battery mounting portion 2c via the handle portion 2b, causing the specific portion 34 to deform the most due to the weight. This deformation is shown in FIG. 6.

[0037] FIG. 6 is a partially enlarged cross-sectional view of the battery mounting portion 2c, the same as FIG. 3(A), illustrating the state of the battery mounting portion 2c when it is dropped in an upright position and subjected to an impact. In the present embodiment, in which the handle portion 2b extends upward perpendicularly from the horizontally extending portion of the battery mounting portion 2c, and an opening 45 for the switch panel 46 (see FIG. 1) is formed on the upper surface of the extension, a specific portion 34 is deformed downward upon impact from a drop. This is because the battery mounting portion 2c of the housing 2 has a large opening 45. The portion of the opening 45 closest to the portion receiving the impact from the handle portion 2b and weakest in strength is subject to the greatest deformation. As a result, the central rear edge of the opening 45 deforms downward, as shown by 34c in FIG. 6, and the portion 34 is pressed into the resin 33. This deformation exerts a force that bends the control circuit portion 30 downward. Forces applied to the control circuit board 31 include compressive stress and bending stress, with bending stress being more likely to crack the board than compressive stress. Bending stress is more likely to cause damage when the force is applied to a portion of the control circuit board 31 close to the center. Therefore, if the portion of the control circuit board 31 close to the center is bent by the impact of dropping the power tool 1, it may break. In contrast, in this embodiment, the beam member 40 is formed below the board case 35, directly below the specific portion 34. Therefore, even if stress is applied to the specific portion 34, deformation that would bend the control circuit unit 30 is suppressed, and damage to electronic components mounted on the control circuit board 31 due to bending of the control circuit board 31 can be effectively suppressed.

[0038] 7 is a cross-sectional view taken along the line CC in FIG. 6, illustrating the state of an impact when the device is dropped in an upright position. A specific portion 34 that deforms due to the impact is near the joint surface of the left-right split housing 2, and as shown in FIG. 7, the area near the central split surface in the left-right direction deforms into a downward convex shape (33a in the figure). Here again, beam members 40 (40-1, 40-2) are disposed below the deforming portion 34 and on the underside of the board case 35, thereby suppressing deformation that bends the control circuit unit 30 (deformation of portion 34) and thereby suppressing the bending force applied to the control circuit board 31.

[0039] FIG. 8 is a top view of the extension of the battery mounting portion 2c and illustrates the switch panel 46. The outer edge of the handle portion 2b near its base is generally circular, and flat extensions are formed forward, to the right, and to the left of the base. The switch panel 46 is located approximately in the center of the extension extending forward. The switch panel 46 is located in an opening 45 formed in the housing 2, and the board case 35 housing the control circuit board 31 is located directly below the opening 45, which is advantageous for wiring and assembly. The switch panel 46 is made of synthetic resin and is equipped with soft-touch switches and an illumination unit. The light switch 47 sets the illumination mode of the illumination device 9. It has two modes: a continuous illumination mode, which illuminates the light for a set period of time (e.g., two minutes) regardless of whether the trigger lever 7a is operated, and a switch-linked illumination mode, which illuminates the light when the trigger lever 7a is operated and then turns it off after a short period of time (e.g., 10 seconds) when the trigger lever 7a is released. Each time the light switch 47 is pressed, the mode switches between continuous illumination mode, switch-linked illumination mode, and off. In continuous illumination mode, the LED 48a lights up, and in switch-linked illumination mode, the LED 48b lights up. When the illumination device 9 is off, neither the LEDs 48a nor 48b lights up. The right side of the switch panel 46 displays a logo and no other switches. However, a switch and multiple LEDs for checking the remaining battery level may be provided, or a tightening mode selector switch and multiple LEDs for switching tightening modes may be provided. The switch panel 46 is manufactured as a separate component from the housing 2 and is fixed so as to be connected to the control circuit board 31. The outer edge of the switch panel 46 is clamped by the opening 45 of the split housing 2.

[0040] In Figure 8, the area surrounded by an oval is the specific region 34 that is susceptible to deformation due to an impact when dropped. The location of the beam member 40 is indicated by the dotted line. When viewing the specific region 34 from above in Figure 8, it can be seen that the specific region 34 is located within the interior area of ​​the beam member 40. Furthermore, the area occupied by the beam member 40 indicated by the dotted rectangular line is positioned so as to partially overlap the area occupied by the switch panel 46. This not only protects the specific region 34 from an impact when dropped, but also effectively counters the weight that tends to deform the control circuit board 31 when the pressing force applied to the switch panel 46 when the switch panel 46 is operated is exerted on the control circuit unit 30. In this way, when a portion of the housing 2, particularly the specific region 34, is deformed due to a drop of the product, the control circuit board 31 can be prevented from being pressed into and damaged by the housing 2.

[0041] As described above, in this embodiment, the beam member 40 is formed inside the battery attachment portion 2c of the housing 2, extending in a direction perpendicular to the dividing plane, and supports the bottom surface 35d (the second surface side of the control circuit board 31) of the board case 35 that houses the control circuit board 31. This significantly reduces the possibility of damage to the control circuit board 31 when the power tool 1 is accidentally dropped. Furthermore, the beam member 40 can be formed simply by changing the injection molding mold for the housing 2, and the control circuit board 31 and the board case 35 can remain in their conventional shapes, making the present invention easy to apply. This is particularly effective in a configuration in which the control circuit unit 30 is disposed across the handle portion 2b and the protruding portion of the battery attachment portion 2c (accommodation portion) that protrudes radially from the handle portion 2b, i.e., a configuration in which the control circuit unit 30 is supported by the battery attachment portion 2c on both the front and rear or left and right sides of the portion 34. This is because a configuration in which the control circuit unit 30 is accommodated (supported) only in the protruding portion reduces the risk of bending even when the control circuit unit 30 is pressed by the portion 34. [Example]

[0042] FIG. 9 is a partially enlarged cross-sectional view of a portion of a housing 2 near a control circuit board 61 according to a second embodiment of the present invention. The second embodiment has the same structure as the first embodiment in that a beam member 40 is formed on the housing 2. However, in addition to the beam member 40, a pillar portion 65e extending upward from a bottom surface 65d (the second surface side of the control circuit board 61) is formed on a portion of the board case 65. The pillar portion 65e is formed directly below a specific portion 34 that is easily deformed by an impact when dropped. The pillar portion 65e is a cylindrical or rectangular pillar-shaped member that penetrates the control circuit board 61 and extends upward to the vicinity of the specific portion 34. The height of the pillar portion 65e is set to the same position as or approximately the same as the upper opening of the board case 65. The pillar portion 65e is formed by integral molding of a non-conductive synthetic resin, similar to the board case 65. The shape and configuration of the pillar portion 65e of the board case 65 are the same as those of the board case 35 of the first embodiment, except for the through-hole 61a. Convex portions 65a and 65b (65a is not visible in FIG. 9) are formed on both the left and right sides of the front, and convex portion 65c is formed on the front edge. Furthermore, through-holes 61a are formed in the control circuit board 61 to allow pillar portions 65e to pass through vertically. The shape of the through-holes 61a is preferably sized appropriately to allow the pillar portions 65e to pass through while positioning the control circuit board 61 within the board case 65. Here, there is almost no gap between the through-holes 61a and the pillar portions 65e, but a gap is acceptable. The periphery of the control circuit board 61 housed within the board case 35 is filled with a curable resin 63. The curable resin is an electrically non-conductive material and is a thin liquid when filled into the board case 35, allowing it to fill every corner of the interior of the board case 35 without gaps. The pillar portions 65e may extend downward from the bottom surface 65d of the board case 65 (the second surface side of the control circuit board 61).

[0043] With the above configuration, when specific portion 34 attempts to deform due to an impact during a drop, as shown in Figures 6 and 7, portion 34 comes into contact with the upper surface of pillar portion 65e. Pillar portion 65e is a member that extends in the vertical direction, and beam member 40 for receiving the weight during an impact is provided on the underside of board case 65 on an extension of its longitudinal axis. In particular, when viewed in a cross-sectional view such as Figure 9, portion 34, pillar portion 65e, and beam member 40 are arranged so as to be aligned in the vertical direction. Therefore, the pillar portion 65e and beam member 40 can firmly receive the weight that attempts to deform due to an impact, thereby preventing the application of strong bending or compressive force to control circuit board 61. [Example]

[0044] 10 is an enlarged partial cross-sectional view of the vicinity of the control circuit section 70 of the housing 2 according to a third embodiment of the present invention. The third embodiment has the same structure as the first embodiment in that the beam member 40 is formed in the housing 2, but is provided with a beam-shaped reinforcing member 76 that spans from the left side to the right side of the outer edge of the opening of the circuit board case 75. The reinforcing member 76 is made of a highly rigid material such as a thin, elongated iron plate or stainless steel plate that has been pressed to increase its strength and then projection processed so that it continues in the longitudinal direction.

[0045] FIG. 11 is a cross-sectional view of the DD portion of FIG. 10 . Two recesses 75e and 75f are formed on the edge of the opening of the circuit board case 75, and both ends of the reinforcing member 76 are positioned in the recesses 75e and 75f. Furthermore, when a downward deformation load is applied from a specific portion 34 near the center of the reinforcing member 76, the deformed portion comes into contact with the center portion 76a of the reinforcing member 76, effectively preventing the deformation load from being directly applied to the control circuit board 31. The material of the reinforcing member 76 is not limited to metals such as iron; it may also be made of a resin member with high bending rigidity, such as carbon, or other high-strength materials. Furthermore, instead of a plate, one or more rods may be used. After the control circuit board 31 with mounted components is placed inside the circuit board case 75, the reinforcing member 76 is appropriately positioned in the recesses 75e and 75f. Then, a curable resin 73 is poured into the circuit board case 75, filling it up to the top surface of the reinforcing member 76. Since the hardening resin 73 also has adhesive properties, the hardened resin 73 holds the reinforcing member 76 stably without rattle.

[0046] 10, the housing 2 is formed with the beam members 40 of this embodiment, but it is also possible to add only the reinforcing members 76 of the third embodiment to a conventional housing 202 (see FIGS. 18 and 19) that does not have the beam members 40. Even with this configuration, the effect of protecting the control circuit board 31 from impact when dropped is sufficient compared to the conventional housing 202. [Example]

[0047] FIG. 12 is a partially enlarged cross-sectional view of the battery attachment portion 2c of the housing 2A according to the fourth embodiment of the present invention. The shape of the housing 2A is substantially the same as that of the conventional housing 202 (see FIGS. 18 and 19), and the beam member 40 is not formed. However, the vertical dimension of the battery attachment portion 202c is increased to provide a sufficient gap 237 below the specific portion 234. This prevents the specific portion 234 from coming into contact with the control circuit unit 30, even if the specific portion 234 is deformed as shown in FIGS. 6 and 7 due to an impact when dropped, or prevents the applied force from becoming too large even if it does come into contact. By providing this gap, stress caused by deformation of the specific portion 234 is not directly transmitted to the control circuit unit 30, and damage to the control circuit board 31 due to an impact when dropped can be prevented.

[0048] FIG. 13 is a cross-sectional view of the EE portion of FIG. 12. It can be seen from this figure that the gap 237 is sufficiently formed. The disadvantages of the fourth embodiment are that the shape of the battery mounting portion 202c of the housing 202 must be changed, albeit very slightly, and that the dimensions of the housing 202 increase slightly in the vertical direction. However, since this only needs to be applied when the design of the housing 202 is changed, it can also be said that the application of the fourth embodiment is easy. The configuration of the fourth embodiment is preferably used in combination with the control circuit units 30, 60, and 70 of the first to third embodiments, rather than being used alone. [Example]

[0049] FIG. 14 is a partially enlarged cross-sectional view of the vicinity of the control circuit unit 80 of a housing 2B according to a fifth embodiment of the present invention. In the fifth embodiment, the control circuit unit 80 is substantially the same as that used in the first embodiment, but the beam member 40 is not formed on the housing 2B but is formed integrally with the terminal holder 55. Furthermore, because the terminal holder 55 is configured to bear the load during an impact, the mounting rigidity of the terminal holder 55 to the housing 2B is significantly increased. Furthermore, multiple ribs 86a, 86b, 87a, and 87b are provided on the inner wall of the battery mounting portion of the housing 2B to firmly hold the terminal holder 55. The terminal holder 55 is a member for securing multiple terminals 57a, 57b, etc., which engage with the connecting terminals of the battery 300. The terminal holder 55 is manufactured by casting a metal plate-shaped member (terminals 57i, 57g, etc.) into the base portion 56 of a non-conductor such as synthetic resin. When the battery 300 is attached or detached, a strong force is applied to the terminal holder 55 in the front-to-rear direction. Therefore, a pair of ribs 86a, 86b extending continuously and parallel to each other in the left-right direction sandwich and hold the front edge (protrusion 55c) of the terminal holder 55, and a pair of ribs 87a, 87b extending continuously and parallel to each other in the left-to-right direction sandwich and hold the rear edge (protrusion 55d) of the terminal holder 55. A butting rib 55f is formed on the lower rear side of the terminal holder 55 and butts against a rib 87c on the inner wall of the housing 2B. A support portion 58 protruding upward is formed on the upper surface of the terminal holder 55. The support portion 58 performs the same function as the beam member 40. When an impact is applied to a specific portion 234 during a drop, the support portion 58 can support the weight applied to the control circuit portion 80. In the fifth embodiment, the shape of the terminal holder 55 is changed to realize a power tool 1 that is designed to withstand impacts during a drop.

[0050] FIG. 15 is a cross-sectional view of the FF portion of FIG. 14. The terminal holder 55 has a total of nine terminals 57a to 57i provided on its base. Terminals 57a and 57b are positive terminals for discharge. Partition plate 57c is a non-conductive, plate-shaped partition member provided to improve insulation between the positive terminals (57a and 57b) and the other terminals (57d to 57i). Terminal 57d is a T terminal for outputting a signal that serves as identification information for the battery 300 to the power tool main body or a charging device. Terminal 57e is a V terminal for inputting a control signal from an external charging device (not shown). Terminal 57f is an LS terminal for outputting battery temperature information from a thermistor (temperature-sensing element) (not shown) provided in contact with the cell. Terminals 57g and 57h are negative terminals (- terminals). Terminal 57i is an LD terminal for outputting an abnormal stop signal from a battery protection circuit (not shown) included in the battery 300. At the FF cross section of the terminal holder 55, a support portion 58 extending upward is formed and comes into contact with the lower surface of the board case 85. The support portion 58 is a convex portion extending continuously in the left-right direction, and its left-right length is formed to be longer than the left-right length of the board case 85. [Example]

[0051] FIG. 16 is a partially enlarged cross-sectional view of the vicinity of the control circuit section 90 of a housing 2B according to a sixth embodiment of the present invention. In the fifth embodiment shown in FIGS. 14 and 15, support portions 58 were formed on the terminal holder 55 side, protruding upward. In the sixth embodiment, however, a convex portion 95f protruding downward is formed on the underside 95d of a container-shaped circuit board case 95, slightly forward of the center in the front-to-rear direction. The rear end of the circuit board case 95 is held by a holding portion 87d that is L-shaped in side view. The upper surface of the terminal holder 55A is formed flat. This configuration allows the support function of the circuit board case of the present invention to be achieved simply by changing the shape of the circuit board case 95 side, without changing the shape of the terminal holder 55.

[0052] FIG. 17 is a cross-sectional view of the GG section in FIG. 16. As shown in this figure, a total of nine terminals 57a to 57i are provided on the base of the terminal holder 55. The allocation of the terminals 57a to 57i is the same as in the example shown in FIG. 15. In the configuration of this embodiment, as in the example of FIG. 15, when viewed in the vertical direction of the GG section, the protrusion 95f and the underside of the terminal holder 55A come into contact. The protrusion 95f extends continuously in the left-right direction, and its left-right length is longer than the left-right length of the board case 95. The terminal holder 55 is a part fixed to the battery mounting part 2c (the housing part that houses the board). [Example]

[0053] FIG. 20 is a perspective view of a control circuit unit 130 of a power tool 101 according to a seventh embodiment of the present invention. The control circuit unit 130 includes a circuit board 131 mounted with a microcomputer and other electronic elements, connectors, and other electronic components (not shown) inside a circuit board case 135, which is a dish-shaped container with an opening at the top, and a switch panel 150 provided on the front side of the circuit board case 135. The components mounted inside the circuit board case 135 are essentially the same as those in the first embodiment. The outer edge shape of the circuit board case 135 is essentially a rectangle when viewed from above, as in the conventional case, but has an octagonal shape with each corner cut off at an angle. The circuit board case 135 is tray- or container-shaped with an opening 136 on the top, and is shaped to prevent leakage even when filled with liquid. The control circuit board 131 has an outer edge shape that follows the shape of the inner wall of the board case 135, and is held inside the housing 102 by sandwiching the board case 135 between the right and left sides of the housing 102. The surface direction of the control circuit board 131 is positioned so as to be perpendicular to the surface direction of the dividing surface of the housing 102. As in the first embodiment, the inside of the board case 135 is filled with a hardening resin (not shown) and allowed to harden. In the first embodiment, the entire outer edge of the control circuit board 131 is fixed by a step formed on the inner wall surface of the board case 135, but in this embodiment, the control circuit board 131 is not fixed around the entire outer edge, but rather is held by a support member formed in a portion near the center.

[0054] Two switches 161, 162 are mounted on the front portion of the board case 135, and a switch panel 150 is provided to form an operation surface. The switch panel 150 forms an operation section exposed to the outside from an opening 104 of the housing 102 (see FIG. 22 described later), and is manufactured by integral molding of synthetic resin. The switch panel 150 has a main portion located above the opening surface 136 of the board case 135, and by extending downward from the main portion, a wall portion that comes into close contact with the inner wall surface of the board case 135 and portions that abut against the control circuit board 131 (ribs 154, flat plate portion 155) are formed. The switch panel 150 has a flat upper surface 151 on the upper side, and two openings 152a, 152b are formed on the upper surface 151 to enable operation of the two switches 161, 162 mounted on the control circuit board 131.

[0055] FIG. 21 is an exploded perspective view of the control circuit unit 130 of FIG. 20. In the seventh embodiment, the method of fixing the control circuit board 131 to the board case 135 differs from that of the first embodiment. Also, similar to the second embodiment shown in FIG. 9, the board case 135 is formed with a support portion (protruding portion 138) that passes through the through-hole of the control circuit board 131 and extends upward. The shape of the board case 135 in a top view is substantially the same as the outer edge shape of the control circuit board 131. It is a tray- or dish-like container with an opening 136 on the upper side, and is formed seamlessly by integral molding of synthetic resin. The protruding portion 138 extends upward from the bottom surface 134 in a funnel-like shape, and is located slightly forward of the center position in a top view.

[0056] A circular step portion 138b is formed near the vertical center of the raised portion 138, and a cylindrical portion 138c is formed on the inner periphery of the step portion 138b, extending upward beyond the step portion 138b. A conical portion 138a below the step portion 138b is conical, with a diameter that increases from top to bottom, and is connected to the bottom surface 134. The funnel-shaped conical portion 138a reduces stress applied from top to bottom. The shape of the conical portion 138a is arbitrary, and as long as the step portion 138b can hold the substrate, the shape of the conical portion 138a is arbitrary. The upper end of the cylindrical portion 138c forms a small annular surface 138d, and a thin, blind hole for a screw is formed in the center. A screw 141 is threaded into the inner hole of the cylindrical portion 138c and tightened until the bottom of the head of the screw 141 abuts the annular surface 138d. If a metal tapping screw is used as the screw 141, it is possible to thread the screw itself into the cylindrical portion 138c while tapping it, as long as there is a pilot hole, even if a female screw is not previously formed inside the cylindrical portion 138c.

[0057] The switch panel 150 has the same width as the circuit board case 135, and its front position is approximately flush with the front wall of the circuit board case 135. The right and left edges of the switch panel 150 are stepped, and the stepped portions abut against the outer edges of the opening 136 of the circuit board case 135. Ribs 153a and 153b are formed below the stepped portions. A rib 153c extending downward is also formed at the center of the lower front edge of the switch panel 150. The bottom surfaces of these ribs 153a, 153b, and 153c abut against the control circuit board 131 and serve to keep the switch panel horizontal when the switch panel is operated. The ribs 153a, 153b, 153c, and 154 are configured so that the control circuit board 131 abuts against the switch panel 150, respectively, thereby maintaining the horizontality of the openings 152a and 152b and the plungers 161a and 162a. Meanwhile, the switch panel 150 and the board case 135 are positioned by the surfaces where the outer peripheries of the ribs 153a, 153b, and 153c come into contact with the board case 135 and by the insertion of the screws 141 into the through holes 156. A rib 154 extending downward is formed near the center in the left-right direction of the rear edge of the board case 135. A tab-like flat portion 155 extends rearward from the rib 154, and a through hole 156 is formed in the center of the flat portion 155. The control circuit board 131, the lower portion of the switch panel 150, the rib 154, and the flat portion 155 are each joined to the board case 135 with a curable resin. The through hole 156 is large enough to allow the cylindrical portion 138c of the raised portion 138 to penetrate through it.

[0058] Two openings 152a and 152b are formed on top surface 151 of switch panel 150 to form a pressing surface that presses plungers 161a and 162a of switches 161 and 162. An elastic resin film (not shown) is provided on the entire top surface 151, including the two openings 152a and 152b, and button indicators that indicate the pressing positions of switches 161 and 162, LED transmission windows, and the like are printed on the film. Five rectangular through-holes 152c and two round through-holes 152d are arranged in the portion of switch panel 150 between openings 152a and 152b, allowing light from LEDs (not shown) mounted on control circuit board 131 to pass through.

[0059] The switches 161 and 162 are, for example, tactile switches. When the operator operates (pushes) the plungers 161a and 162a, the switch 161 or 162 is energized. The plungers 161a and 162a are biased upward by springs, i.e., to a state where the switches are turned off. Therefore, the switches perform a "momentary operation" in which the switches are turned on when the plungers 161a and 162a are pressed in and turned off when the pressed state is released. Multiple terminals (for example, four, not shown) protrude from the bottom of the switches 161 and 162 that house the plungers 161a and 162a, and the terminals are fixed to the control circuit board 131 by soldering.

[0060] The control circuit board 131 has a first surface (top surface) facing the opening surface 136, and a second surface (bottom surface) on the opposite side. Two through holes 132a and 132b and two rectangular cutouts 132c and 132d are formed in the control circuit board 131. The through hole 132a determines the vertical position of the control circuit board 131 by abutting against a step portion of a support portion (raised portion 138) described below. The through hole 132a is a hole for passing a screw 142 through. The cutouts 132c and 132d are formed to allow cables and the like to pass from the bottom surface to the top surface, but if there is no need to pass cables and the like, the cutouts 132c and 132d do not need to be formed.

[0061] The board case 135 is formed by integral molding of synthetic resin such as plastic, and a step 137 for supporting the control circuit board 131 is formed along the front wall. The step 137 is approximately half the height of the inside of the board case 135, so that when the control circuit board 131 is installed, the bottom surface of the control circuit board 131 does not come into contact with the bottom surface 134 of the board case 135. No step is formed on the inner wall portions 135c and 135d on the parallel right sides of the control circuit board 131. Therefore, no support portions are formed downward near the right and left edges of the control circuit board 131. The screw 142 is threaded into the board case 135 through the through hole 132b. However, a small cylindrical screw boss 139 (not visible in the figure), which will be described later, is formed in the lower portion of the through hole 132b.

[0062] FIG. 22 is a perspective view showing the state in which the control circuit unit 130 in FIG. 20 is attached to the housing 102. Only the right side of the housing 102 is shown here, and the left side of the housing 102 is not shown. The board case 135 is sandwiched between the left and right sides of the housing 102 by fitting into beams and recesses formed on the inner sidewalls of the housing 102. An opening 120 is formed on the underside of the board case 135 for fastening the terminal holder 50 (see FIG. 3). As can be seen in this figure, the screw 141 is positioned at a position that passes through the vertical dividing plane of the housing 102 and is located directly below the specific portion 104 that is most susceptible to deformation due to an impact when dropped. Furthermore, the underside of the specific portion 104 and the screw 141 are kept out of contact under normal conditions.

[0063] An upper surface 151 of the switch panel 150 fixed to the upper side of the board case 135 is provided so as to be exposed to the outside through an opening 103 of the housing 102. The opening 103 is formed so as to straddle the dividing surface from the right side to the left side of the battery mounting portion 102c of the housing 102. Although the film 160 provided on the switch panel 150 is not shown in FIG. 22 , covering the entire upper surface 151 with the film 160 can prevent dust and water from reaching the control circuit board 131.

[0064] FIG. 23 is a partially enlarged cross-sectional view of the battery attachment portion 102c of the power tool 101 according to the seventh embodiment. FIG. 23(A) is a longitudinal cross-sectional view taken along the left-right dividing plane of the housing 102. The board case 135 is positioned perpendicular to the dividing plane of the left-right dividing housing 102 and is fixed by being sandwiched between the right and left halves of the housing 102. The front lower side of the board case 135 is supported by a support surface 121a formed on the inner wall of the housing 102. A rib 122 extending in the up-down and left-right directions is formed approximately near the center of the board case 135 in the front-to-rear direction. The rib 122 is positioned near the location where local deformation of the housing occurs upon impact due to a drop, i.e., near the location of the screw 141. The projected area of ​​the protrusion 138 in the downward direction partially overlaps with the area where the rib 122 is positioned when viewed from above. This positional relationship allows the rib 122, which acts as a beam, to effectively absorb impacts acting from above and below the protrusion 138. The rib 122 also serves as a member that forms part of the front edge of the opening 120 formed in the housing 102 for attaching the terminal holder 50 (see FIG. 3). The upper rear portion and lower rearmost portion of the board case 135 are not held by the rib and are left free. Therefore, when the switch panel located on the upper front side of the board case 135 is operated, the housing 102 supports the board case 135, but when the power tool receives a strong impact due to being dropped, etc., the board case 135 can change its position, which has the effect of reducing deformation that occurs in the board case 135 and the control circuit board 131.

[0065] The load of the center portion of the control circuit board 131 is supported by a raised portion (support portion) 138 formed integrally with the circuit board case 135. If a heavy load is not applied to the control circuit board 131 during normal use, it is sufficient to hold the control circuit board 131 with only the raised portion 138 and harden it with a hardening resin. However, in a power tool, not only unexpected heavy loads caused by a drop impact but also vibrations applied during operation are transmitted to the control circuit board 131. Therefore, to prevent the control circuit board 131 from moving downward relative to the circuit board case 135, the lower front edge of the control circuit board 131 is supported by a stepped portion 137 formed in the circuit board case 135. Furthermore, by fixing the rear end of the control circuit board 131 with a screw 142, it is possible to prevent the control circuit board 131 from becoming distorted and tilting when the case is filled with hardening resin. In this way, the control circuit board 131 is always installed in the correct position, and at the same time, it is possible to prevent the switch panel 150 from moving up and down when it is operated.

[0066] A screw boss 139 is formed in the center of the rear of the board case 135, and a screw 142 is threaded into the screw boss 139 to secure the control circuit board 131. The screw boss 139 is a cylindrical member that is integrally formed with the board case 135 during injection molding. In this embodiment, the parallel right and left edges of the control circuit board 131 are not supported in the vertical direction and are free to move. No members that abut against the underside of the control circuit board 131 are formed on either side of the screw boss 139. The screw boss 139 is preferably positioned in the center of the horizontal direction so that it is on the dividing plane of the housing 102. However, the position of the screw 142 does not need to be strict, and it does not matter if it is slightly offset laterally from the dividing plane. Although FIG. 23(A) shows the screw boss 139 positioned near the rearmost end of the inner side of the board case 135, the screw boss 139 may be positioned slightly forward of the rearmost end.

[0067] A switch panel 150 is provided on the front upper side of the circuit board case 135. Operation buttons are printed on the top surface of the switch panel 150, and a film 160 on which a transmission window for light from an LED is printed is attached. An operator can operate switches 161 and 162 by slightly pressing the button portion downward from above the film 160.

[0068] The shape of the opening 120 for attaching the terminal holder 50 (see FIG. 3), the shapes of the rail groove 52-1, the rail portion 53-1, the latch groove 54-1, etc. are formed in the same manner as in the first embodiment. Between the ribs 122 and 124, the upper connection terminals of the terminals 57a to 57i (see FIG. 15) fixed to the terminal holder 50 (see FIG. 3) are arranged.

[0069] 23(B) is a cross-sectional view of part II in FIG. 23(A). Board case 135 is sandwiched by housing 102 via rib 121b, horizontal rib 106, and the like. Through-hole 132a formed approximately in the center of control circuit board 131 is a hole that is sufficiently larger than not only screw 141 but also cylindrical portion 138c of protrusion 138 (see FIG. 21 for the symbol). Therefore, the center of control circuit board 131 is not restricted in the up and down direction by screw 141. In addition, the curable resin that covers the entire control circuit board 131 has a certain degree of elasticity, allowing control circuit board 131 to move slightly relative to protrusion 138.

[0070] FIG. 24 shows a board case 135 of a seventh embodiment, where (A) is a top view, (B) is a cross-sectional view of portion KK in (A), and (C) is a cross-sectional view of portion LL in (A). The interior of board case 135 is formed with three support portions for supporting control circuit board 131 from below. The most important feature in this embodiment is raised portion 138, located near the lateral center and near the position where a specific portion of housing 102 deformed by an impact during a drop will first strike control circuit board 131. Raised portion 138 serves two purposes: first, to determine the vertical position of control circuit board 131; and second, to allow a specific portion of deformed housing 102 to strike the raised portion, thereby transmitting the impact to beam portions of housing 102 (such as ribs 122-124 shown in FIG. 23) via board case 135, rather than to control circuit board 131. Below step 138b of raised portion 138, conical portion 138a is formed, which has a conical shape or an inverted funnel shape with a diameter that increases as it approaches bottom surface 134. The reason for using such a conical shape is to disperse impacts applied to raised portion 138 via screw 146 and transmit them to bottom surface 134, thereby preventing stress from concentrating in a localized area of ​​board case 135. By using conical portion 138a, it is possible to prevent a reduction in the mounting area of ​​electronic elements mounted on the underside of control circuit board 131.

[0071] A cylindrical portion 138c is formed above the conical portion 138a. The cylindrical portion 138c serves as a screw boss for fastening a screw. The upper surface of the cylindrical portion 138c forms a small-diameter annular surface 138d. The screw 141 is made of metal, and even if a strong impact is applied from above downward, the impact point will not be destroyed, and the impact can be effectively dispersed and transmitted from the raised portion 138 to the bottom surface 134. The portion where this screw 142 is provided is approximately directly below the specific portion of the handle portion 102b of the housing 102 that is most susceptible to deformation. Note that the screw 141 is not essential, and the cylindrical portion 138c may be configured to have a columnar shape without providing the screw 141 so as to withstand the load. The left and right sides of the control circuit board 131 are in contact with the inner wall surface of the board case 135 or are separated by a small distance and in a non-contact state. With this configuration, even if a strong impact is applied downward from above to the top of screw 141, a strong direct force is unlikely to be applied to control circuit board 131. Furthermore, even if a strong downward force is applied near the center of control circuit board 131, the left and right sides of control circuit board 131 are not fixed to board case 135, and protrusion 138 is not fixed to control circuit board 131, so control circuit board 131 can slide vertically relative to deforming board case 135, and excessive force is unlikely to be applied to control circuit board 131.

[0072] The area near the front edge of control circuit board 131 is held in a state where the underside is placed on step portion 137. Therefore, control circuit board 131 cannot move downward, but can move upward. The area near the rear edge of control circuit board 131 is fixed to board case 135 by second screw 142. Therefore, control circuit board 131 is directly screwed to control circuit board 131 only by rear-side screw 142. Because control circuit board 131 is screwed in only one location, even if control circuit board 131 is deformed in a location other than the screw-fastened location, it can slide relative to board case 135, so stress is not concentrated in a specific location on control circuit board 131, and damage to the mounted elements and circuit patterns can be effectively prevented.

[0073] Well-known electronic elements such as a one-chip microcomputer, resistors, capacitors, coils, and switches are mounted on the upper and lower surfaces of the control circuit board 131. To enable double-sided mounting, a predetermined gap is provided between the lower surface of the control circuit board 131 and the bottom surface 134 of the board case 135. Also, a predetermined gap is provided between the upper surface of the control circuit board 131 and the opening surface 136 of the board case 135.

[0074] FIG. 25 is a partial enlarged view of portion M in FIG. 23. As can be seen in this enlarged view, the height of cylindrical portion 138c extending upward from step portion 138b is slightly higher than the combined height of control circuit board 131 and flat portion 155 of switch panel 150. Therefore, fastening by screw 141 does not completely restrict the vertical movement of control circuit board 131 and switch panel 150. Furthermore, the size of through-hole 132a in control circuit board 131 is sufficiently larger than the size of cylindrical portion 138c. Screw 141 is made of metal, and its top has a gap between it and specific portion 104 of housing 102. Therefore, during normal operation, housing 102 and screw 141 remain out of contact. However, if housing 102 is dropped while upright, specific portion 104 will deform downward and come into contact with the top of screw 141. Although screw 141 is connected to board case 135, it is not firmly fixed to control circuit board 131 and switch panel 150. In other words, although protrusion 138 restricts movement of control circuit board 131 in the front-to-back, left-to-right, and up-down directions to some extent, it does not completely fix control circuit board 131 to board case 135. Therefore, it is possible to significantly prevent strong force from being applied to control circuit board 131 due to deformation of specific portion 104 of housing 102 caused by the impact of being dropped, and therefore it is possible to significantly reduce the risk of damage to electronic components mounted on control circuit board 131.

[0075] 25, the inner space of board case 135 is filled with a liquid hardening resin and hardened so that all or almost all of the electronic components mounted on control circuit board 131 are covered with the resin. The resin is preferably filled to a height from bottom surface 134 to near opening surface 136, at least to the extent that the heads of screws 141 are completely hidden.

[0076] FIG. 26A is a top view of the control circuit unit 130 of the seventh embodiment, and FIG. 26B is a top view of a conventional control circuit unit 230. In FIG. 26A, the screws 141, 142 and the electronic elements mounted on the control circuit board 131 are omitted. The portion of the board case 135 that contacts the lower front edge of the control circuit board 131 (step portion 137) is indicated by a dotted line. The board case 135 has a step portion 137a (see also FIG. 21) that is continuous in the left-right direction on the inside of the front edge portion 135a. The shape of the board case 135 resembles a rectangle with the corners cut diagonally when viewed from above, and steps 137b and 137c are also formed on the inside of the step portion, thereby stably holding the lower front portion of the control circuit board 131. Furthermore, the front portion of the control circuit board 131 and the step portion 137 are not firmly fixed with screws or the like, but are simply placed on top of each other, or are only lightly supported by weak contact resistance with the ribs 137f, 137g (see Figure 21) extending in the vertical direction.

[0077] A raised portion 138 that supports the underside of the control circuit board 131 is provided near the center of the control circuit board 131. The raised portion 138 is preferably located at the lateral center, which is located at a position that passes through the dividing surface of the housing 102. When viewed from the front to back, the raised portion 138 is located slightly forward of the center point. This is because, when switches 161 and 162 arranged on the control circuit board 131 are pressed, a downward force is applied to the control circuit board 131. The raised portion 138 must resist this force. The plungers of the switches 161 and 162 are each included within a pentagonal (approximately triangular) area enclosed by the steps 137, including the imaginary line 36a connecting the rightmost position 137d of the stepped portion 137b to the rear contact point of the stepped portion 138b of the raised portion 138, and the imaginary line 36b connecting the leftmost position 137e of the stepped portion 137c to the rear contact point of the stepped portion 138b of the raised portion 138. By adopting such a positional relationship, the force applied to control circuit board 131 when switch 161 or switch 162 is operated can be effectively transmitted to board case 135, and switch panel 150 can be well supported with minimal contact between board case 135 and control circuit board 131. This makes it possible to achieve both a reduction in the stress generated in control circuit board 131 due to deformation of board case 135 when dropped and good operability of switch panel 150.

[0078] A through hole 132b through which a screw 142 (see FIG. 21) is inserted is formed on the rear side of the control circuit board 131. Furthermore, a screw boss 139 with a screw hole is formed on the board case 135. The positions of the screw boss 139 and the through hole 132b are preferably aligned with the dividing surface of the housing 102 or are close to the dividing surface. The rear side of the raised portion 138, except for the screw boss 139, is raised above the board case 135. Therefore, even if a strong downward impact is applied from directly above the screw 141 of the board case 135, the impact is transmitted directly to the board case 135 via the raised portion 138, which effectively prevents excessive force that might distort the control circuit board 131. Furthermore, even if a force that might distort the board case 135 is applied, the force is not easily transmitted to the control circuit board 131, effectively reducing the risk of damage to the circuit elements mounted on the control circuit board 131.

[0079] 26(B) is a top view of conventional circuit board case 235 and control circuit board 231. The shape of control circuit board 231, the shape of circuit board case 235, and the arrangement of switches 161 and 162 are not identical, but this is the result of matching them to the shape of the housing. However, the underside of control circuit board 231 is held by stepped portion 236 around the entire outer edge. Therefore, when a strong downward impact is applied to a specific part of the housing, most of the force is received by the entire surface of control circuit board 231.

[0080] Switch panel fixing holes 232a and 232b are holes provided in control circuit board 131 for fixing a conventional switch panel (not shown). In the conventional switch panel, fixing hooks (not shown) are provided on the underside of the switch panel, and the fixing hooks are inserted into fixing holes 232a and 232b, respectively, and hooked onto the underside of control circuit board 131. In addition, an elastic body (not shown) is provided on the top surface of control circuit board 131 to bias control circuit board 131 against the fixing hooks, thereby stably fixing the switch panel. As described above, the conventional board case 235 had the problem of high costs due to the use of an elastic body. However, in the present invention, only a minimum number of screws and hardening resin are used to fix the switch panel, which not only reduces stress generated in control circuit board 131 but also reduces the number of parts (cost reduction).

[0081] FIG. 27 is a partial enlarged view of the vicinity of the support portion of the control circuit board 131 according to a modification of the seventh embodiment. The shape of the support portion, or protrusion 188, differs from the shape shown in FIG. 25. Protrusion 188 has the same shape as conical portion 188a and stepped portion 188b, which protrude from the bottom surface of board case 185, but the height (axial length) of cylindrical portion 188c is reduced. The height of cylindrical portion 188c is greater than the thickness of control circuit board 131, and the positional relationship between flat portion 155 of switch panel 150 and control circuit board 131 is such that there is no strong contact between them. Even in this modification, a small gap is formed between specific portion 104 and the top surface (opening 186) of board case 185. Therefore, vibrations transmitted from housing 102 to control circuit board 131 during normal operation are kept small.

[0082] FIG. 28A is a diagram showing the position of stress transmitted from the maximum deformation point of housing 102 to board case 135 in the seventh embodiment. In FIG. 28A, when a strong downward force as indicated by arrow 148 is applied from a specific portion, specific portion 104 of housing 102 is distorted downward and comes into contact with screw 141. The force applied downward in the axial direction of screw 141 is transmitted from board case 135 to rib 121 and the like. In this way, the force of screw 141 is transmitted from conical portion 138a to the entire board case 135, and can be effectively supported by rib 121 (ribs 121a and 121b in FIG. 23), rib 122, and the like as indicated by arrow 149. Because ribs 121 and 122 are formed continuously from the right side surface to the left side surface of housing 102, the rigidity can be increased, thereby reducing the risk of damage to housing 102.

[0083] FIG. 28(B) shows the location of stress transmitted from the maximum deformation point of conventional housing 202 to board case 135. In conventional housing 202, a force applied to a specific portion, as indicated by arrow 248, is transmitted to control circuit board 231 and then to board case 235 via a step on the lower outer edge of control circuit board 231. The force applied to control circuit board 231 is supported by step 236 of board case 235 in the directions indicated by arrows 249a and 249b. In this way, deformation due to a strong impact, such as a fall, passes through control circuit board 231 during transmission to housing 202 below board case 235, making electronic elements mounted on control circuit board 231 more susceptible to damage. On the other hand, if the force is configured to be transmitted directly to housing 202 via protrusion 138 as shown in FIG. 28(A), the risk of damage to control circuit board 231 is reduced. [Example]

[0084] FIG. 29 is a cross-sectional view showing the control circuit unit 130 of a power tool 101 according to an eighth embodiment of the present invention. (A) is a vertical cross-sectional view passing through the dividing plane of the housing 102, and (B) is a longitudinal cross-sectional view perpendicular to (A). The eighth embodiment differs from the seventh embodiment in that the board case 135A does not include switches 161 and 162. If the switches 161 and 162 are not provided, the housing 102 does not have an opening for a switch unit. Furthermore, a step corresponding to the step portion 137 (see FIG. 24) on the inside of the front wall of the board case 135A shown in FIG. 24 does not need to be formed. However, the shape of the board case 135A itself is the same as that of the seventh embodiment, and the vibration transmission path when a specific portion 104 of the housing 102A is deformed downward is also substantially the same as the example shown in FIG. 28(A).

[0085] The cross-sectional shape in Fig. 29(B) is substantially the same as that in Fig. 23(B). In the eighth embodiment, the outer diameter of cylindrical portion 138c is also sufficiently smaller than through-hole 132a, so that the vertical movement of control circuit board 131 is not restricted by screw 141. However, since the inner space of board case 135A is almost entirely filled with hardening resin, control circuit board 131 does not move excessively.

[0086] While the present invention has been described above based on the first to eighth embodiments, it is not limited to these embodiments and various modifications are possible without departing from the spirit and scope of the present invention. For example, while the above embodiments have been described using an impact tool as an example of the power tool 1, the present invention is not limited to impact tools and can be applied to other battery-powered tools in which a battery attachment portion is formed at the tip of the handle and a battery and a circuit board are provided. Furthermore, the present invention is not limited to battery-powered cordless power tools and can be applied to corded power tools that are operated by connecting the power cord to an external power source such as a commercial power source. When applied to a corded power tool, the battery attachment portion 2c may be formed as a storage portion with a closed shape below the battery attachment portion 2c, and the storage portion may be divided like the body and handle of the housing, with an opening formed so as to intersect the dividing plane, a switch panel attached to the opening, and the control circuit unit 30, 60-90 may be housed inside the storage portion. [Explanation of symbols]

[0087] 1 Power tool 2, 2A, 2B Housing 2a Body part 2b Handle 2c Battery mounting part 3 Motor 3a Rotor 3b Stator 4 Rotating shaft 5 Hammer case 5a Through hole 6 Soft layer 7 Trigger switch 7a Trigger lever 8 Forward / reverse switching lever 9 Lighting device 10 Output shaft 10a Mounting hole 11 mounting mechanism 12 inverter circuit board 13 position detection element 14 Semiconductor switching element 15 Rotor fan 16a, 16b Bearings 17a, 17b Air intake 17c Air exhaust 18a, 18b Bearing 19c~19j Screw boss 20 Reduction mechanism 21 Impact mechanism 22 spindle 23 spindle cam groove 24 hammer 25 Hammer cam groove 26 Steel ball 27 Hammer spring 28 Anvil 29a~29h Screws 30 Control circuit section 31 Control circuit board 33 Resin 34 Specific part (of housing) 35 Circuit board case 35a, 35b, 35c Convex parts 35d Bottom surface 35e recess 36A weight 37 wall 38c recess 39a, 39b Ribs 40, 40A Beam member (support part) 43a~43d (Handle) base area 45 Opening 46 Switch panel 47 Light switch 48a, 48b LED 50 Terminal holder 51a, 51b Recessed portion 52-1, 52-2 Rail groove 53 Rail section 54 Latch groove 55, 55A Terminal holder 55c, 55d Convex part 55f Rib 56 Base part 57a-57b, 57d-57i Terminal 57c Partition plate 58 Support section 60 Control circuit section 61 Control circuit board 61a Through hole 63 Resin 65 Board case 65a, 65b, 65c, 75b Convex part 65d Bottom surface 65e Pillar part 70, 80, 90 Control circuit part 73, 83 Resin 75, 85, 95 Circuit board case 75e Recess 76 Reinforcement member 85f Convex part 86a, 86b Ribs 87a~87c Ribs 87d Holding part 95d Bottom surface 95f Convex part 101 power tool 102 housing 102b handle portion 102c Battery mounting portion 103 Opening 104 (Housing) Specific Part 120 Opening 121a Retaining surface 121b Rib 122~125 Rib 125 Step portion 130 Control circuit portion 131 Control circuit board 132a Through hole 132b Through hole 132c Notch 134 bottom surface 135 board case 135a (board case) front edge 135c, 135d (board case) inner wall portion 136 opening surface 137, 137a to 137c Stepped portion 137d Rightmost position (of the stepped portion) 137e (Step) leftmost position 137f, 137g Rib 138 raised portion 138a conical portion 138b step portion 138c Cylindrical portion 138d Annular surface 139 Thread boss 141, 142 Screws 146 Screws 150 Switch panel 151 Top surface 152a, 152b Opening 152c, 152d Through hole 153a, 153b, 154 Rib 155 Flat plate portion (tab) 156 Through hole 160 Film 161, 162 Switch 161a, 162a Plunger 185 Board case 186 Opening 188 raised portion 188a conical portion 188b step portion 188c cylindrical portion 202 housing 202b handle portion 202c Battery mounting portion 231 Control circuit board 232a, 232b Switch panel fixing holes 234 (specific) part 235 Circuit board case 236 Step 237 Gap 238a, 238b Ribs 238c Recesses 239a, 239b Ribs 300 Battery 301 Latch button A1 (motor and output shaft) axis B1 (handle part) central axis C1 (Battery mounting part) left and right center line (separation plane)

Claims

1. A motor; a housing having a body portion that houses the motor and a handle portion that extends downward from the body portion and is gripped by an operator, the housing having a dividing surface that divides the housing in a left-right direction that is a dividing direction; a control circuit unit including a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and a resin filled in the board case so as to immerse the upper and lower surfaces of the control circuit board; a housing portion provided below the handle portion, the housing portion having a protruding portion protruding forward and in left and right directions from the handle portion, the housing portion housing the control circuit portion; an input / output operation unit provided on an upper surface of the protruding portion so as to extend in the left-right direction, and used by an operator to perform input operations; an opening extending in the left-right direction on the upper surface of the protruding portion and divided by the dividing surface, the opening having an outer edge that holds the input / output operation unit so as to sandwich the input / output operation unit in the dividing direction; A power tool comprising: the outer edge has a portion where the outer edge of the opening on the handle portion side intersects with the dividing surface, and the portion is located above the control circuit unit and faces the control circuit unit; a first support portion for supporting the control circuit portion from below, the first support portion being located inside the housing portion below the control circuit portion in the up-down direction and coinciding with the position of the control circuit portion in the front-rear and left-right directions; A power tool characterized by:

2. The power tool according to claim 1, The power tool, wherein the first support portion is integrally formed with the housing.

3. The power tool according to claim 1, The storage section is configured as a battery mounting section into which a battery can be attached, a terminal holder supported by the housing in the accommodating portion, the terminal holder having a terminal connectable to a terminal of a battery, the terminal holder being located below the control circuit board in a vertical direction and facing the control circuit board; The power tool, wherein the first support portion is formed integrally with the terminal holder.

4. The power tool according to claim 1, An electric power tool characterized in that it has a second support portion extending upward from the bottom surface of the base case directly below the portion, and the portion, the first support portion, and the second support portion are arranged in a vertical line.

5. The power tool according to claim 1, An electric power tool characterized in that it has a second support portion extending upward from the bottom surface of the board case at a position directly below the portion, the second support portion passing vertically through a through hole formed in the control circuit board, and the control circuit board is configured to extend from the front to the rear of the second support portion.

6. A motor; a housing having a body portion that houses the motor and a handle portion that extends downward from the body portion and is gripped by an operator, the housing having a dividing surface that divides the housing in a left-right direction that is a dividing direction; a control circuit unit including a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and a resin filled in the board case so as to immerse the upper and lower surfaces of the control circuit board; a housing portion provided below the handle portion, the housing portion having a protruding portion protruding forward and in left and right directions from the handle portion, the housing portion housing the control circuit portion; an input / output operation unit provided on an upper surface of the protruding portion so as to extend in the left-right direction, and used by an operator to perform input operations; an opening extending in the left-right direction on the upper surface of the protruding portion and divided by the dividing surface, the opening having an outer edge that holds the input / output operation unit so as to sandwich the input / output operation unit in the dividing direction; A power tool comprising: the outer edge has a portion where the outer edge of the opening on the handle portion side intersects with the dividing surface, and the portion is located above the control circuit unit and faces the control circuit unit; a first support portion that supports the control circuit portion from below and is located below the control circuit portion in the vertical direction inside the accommodation portion; a second support portion extending upward from the bottom surface of the board case at a position directly below the portion, and the portion, the first support portion, and the second support portion are arranged in a vertical direction; A power tool characterized by:

7. The power tool according to claim 6, The power tool, wherein the first support portion is integrally formed with the housing.

8. The power tool according to claim 6, The storage section is configured as a battery mounting section into which a battery can be attached, a terminal holder supported by the housing in the accommodating portion, the terminal holder having a terminal connectable to a terminal of a battery, the terminal holder being located below the control circuit board in a vertical direction and facing the control circuit board; The power tool, wherein the first support portion is formed integrally with the terminal holder.

9. A motor; a housing having a body portion that houses the motor and a handle portion that extends downward from the body portion and is gripped by an operator, the housing having a dividing surface that divides the housing in a left-right direction that is a dividing direction; a control circuit unit including a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and a resin filled in the board case so as to immerse the upper and lower surfaces of the control circuit board; a housing portion provided below the handle portion, the housing portion having a protruding portion protruding forward and in left and right directions from the handle portion, the housing portion housing the control circuit portion; an input / output operation unit provided on an upper surface of the protruding portion so as to extend in the left-right direction, and used by an operator to perform input operations; an opening extending in the left-right direction on the upper surface of the protruding portion and divided by the dividing surface, the opening having an outer edge that holds the input / output operation unit so as to sandwich the input / output operation unit in the dividing direction; A power tool comprising: the outer edge has a portion where the outer edge of the opening on the handle portion side intersects with the dividing surface, and the portion is located above the control circuit unit and faces the control circuit unit; a second support portion extending upward from the bottom surface of the board case at a position directly below the portion, the second support portion vertically passing through a through hole formed in the control circuit board, and the control circuit board extending from the front to the rear of the second support portion; A power tool characterized by:

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