Electric power tool

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 an electric power tool that is provided with measures against shocks caused by dropping or the like. [Background technology]

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

[0003] In an electric tool such as that disclosed in Patent Document 1, a handle portion is formed extending from approximately the center of a body portion in a direction approximately perpendicular to the axial direction, and a battery attachment portion is provided at the tip of the handle portion and at a position away from the body portion (the end portion opposite the body portion). The battery attachment portion extends in a direction intersecting with the axis of the handle portion, and a pack-type battery is attached to its underside. 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. On the switch panel, soft-touch buttons for setting the motor rotation speed and impact strength, a switch for turning on a lighting device provided near the output shaft, etc. are provided. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-124725 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of handheld power tools, the power tool may be dropped to the ground or the like due to carelessness of the worker. For this reason, power tool manufacturers have been improving power tools to prevent them from breaking as much as possible when dropped by implementing shock countermeasures when dropped. There are various parts that receive shock when dropped, but in the process of implementing shock countermeasures, the inventors found that, for example, in the case of a battery-powered power tool, when a power tool 1 with the battery at the bottom is dropped from a position higher than the normal working position, the vicinity of the base of the handle part and the battery mounting part may be deformed, and the control circuit board arranged below may be damaged. It was also found that the deformation near the connection part between the handle part and the battery mounting part becomes particularly large when an opening is provided for arranging a switch panel near the upper surface of the extending part of the battery mounting part. In addition, some power tools that use commercial power sources, rather than cordless power tools, have a housing part for housing a circuit board at the end of the handle, and there is a risk that the circuit board may be damaged due to deformation of the housing part when 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 portion 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-mentioned background, and its object 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 to the ground or the like. Another object of the present invention is to provide an electric 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. Yet another object of the present invention is to provide an electric 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 tool comprising: a motor, a body portion for accommodating the motor, a housing having a dividing surface in the left-right direction which is a 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 operation portion provided on an upper surface of the protruding portion so as to extend in the left-right direction and for an operator to perform input operations; and an opening provided on the upper surface of the protruding portion so as to extend in the left-right direction and be divided by the dividing surface, the opening having an outer edge that holds the input / output operation portion in such a way that it is sandwiched in the dividing direction, the outer edge has a portion where an outer edge on the handle portion side of the opening and the dividing surface intersect, 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 immediately 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 edges on both the left and right sides of the substrate are held in a non-contact state with the housing. A step or support is provided in front of the housing to support the underside of the front edge of the substrate. A gap is provided between the substrate 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 substrate, 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 substrate, and the support is adapted to suppress deformation of the edge of the opening.

[0009] According to another feature of the present invention, there is provided a power tool having a housing, a motor accommodated in the housing, a power transmission mechanism for transmitting the torque of the motor to a tool tip, and a control unit for controlling the rotation of the motor, the housing having a handle and a battery attachment unit formed at the tip of the handle, the battery attachment unit having an extension extending in a direction intersecting with the axial direction of the handle, the housing being of a type that is sandwiched between the left and right, an opening is formed in the extension so as to straddle the sandwiching division surface at a surface intersecting with the axial direction, and the battery is attached to the extension on the side opposite the handle. In the power tool having such a configuration, a control circuit board mounting the control unit is provided between the battery and the handle inside the extension, the control circuit board is held by being sandwiched between the two-part housing, and a support unit is provided that directly or indirectly holds the control circuit board in a direction perpendicular to the division surface. The support unit is provided at a position that overlaps with a part of the periphery of the opening when viewed in the longitudinal direction (B1 direction) of the handle.

[0010] According to yet another feature of the present invention, the control circuit board is housed in a container-shaped board case having a convex portion formed on the side of the two-split housing in the split direction, and the convex portion of the board case is held by being sandwiched between a concave portion 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 split direction on the lower surface of the board case. The beam portion is preferably formed by integral molding with the housing, and a part of the periphery of the opening and a part of the beam portion are provided at a position overlapping with the longitudinal direction (B1 direction) of the handle portion. Here, it is preferable that the length of the beam portion is formed larger than the width of the control circuit board. Also, the board case may be configured to have a pillar portion formed from the bottom surface to the upper opening, and a through hole for passing the pillar portion through the control circuit board may be formed.

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

[0012] According to still another feature of the present invention, the motor is accommodated in the housing, the handle is held by the operator, and the housing is provided at an end of the handle and protrudes radially from the handle, and accommodates a substrate on which electronic components are mounted. The substrate is accommodated in the housing from a position on the extension of the handle to a protruding portion of the housing. An opening is formed in the protruding portion of the housing at a position facing the substrate, and a support portion is provided in the housing to suppress deformation of the edge of the opening. The substrate is accommodated in the housing so as to face the edge, and the support portion is integrally configured with the housing so as to support the substrate on the opposite side of the edge with respect to the substrate. The substrate has a first surface (upper opening surface) facing the edge and a second surface (bottom surface) opposite the edge with respect to the first surface, and is accommodated in the housing while being accommodated in the substrate case. The support portion is provided in the substrate case so as to extend from the second surface side through the substrate to the first surface side of the substrate, or to extend from the second surface side to the opposite side of the substrate and contact a portion fixed to the housing. The substrate is accommodated in the accommodation section so as to face the edge portion, and another support section may be provided between the edge portion and the substrate. The accommodation section may have a terminal holder that constitutes a battery attachment section for attaching a battery and that is provided with a tool side terminal that connects to a battery side terminal of the battery, the terminal holder may be provided on the opposite side of the substrate from the edge portion so as to face the substrate, and the support section may be provided on the terminal holder.

[0013] According to yet another feature of the present invention, the device includes a body that houses a motor, a handle that is gripped by an operator, and a housing that is provided at an end of the handle and protrudes radially from the handle for housing a circuit board on which electronic components are mounted, the circuit board is housed in the housing from a position on the extension of the handle to the protruding portion of the housing, and an opening is formed in the protruding portion of the housing 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. Effect of the Invention

[0014] According to the present invention, even if a specific portion of the housing is deformed and a pressing force due to the deformation acts on the circuit board when an impact such as a drop is applied to the housing of the power tool, the support portion arranged under the circuit board suppresses the deformation of the circuit board, so that the power tool failure caused by the damage of the circuit board can be effectively suppressed. In addition, the support portion can be manufactured as a beam portion extending in a direction perpendicular to the housing dividing surface by integral molding with the housing, so that the strength can be increased and an increase in manufacturing costs can be suppressed. Furthermore, the other support portion is configured as a metal plate that connects two sides of the circuit board case in a direction perpendicular to the dividing surface, so that the present invention can be easily implemented by simply changing the circuit board case. [Brief description of the drawings]

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

[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 uses a rechargeable battery pack 300 as a power source and a motor as a drive source to apply a rotational force and an impact force to an output shaft 10, and transmits the rotational impact force intermittently to a tip tool (not shown), such as a driver bit, that is attached to a mounting hole 10a and held by a mounting mechanism 11, to perform work such as screwing or bolting. The housing 2 of the power tool 1 is made up of three parts: a substantially cylindrical tubular body 2a for accommodating the motor and the power transmission mechanism, a handle 2b that extends from the approximate center of the body 2a in a direction substantially perpendicular to the axis A1 (downward) and is held by an operator with one hand, and a battery attachment part 2c that is provided at a lower end (opposite the body end) of the handle 2b on the opposite side to the body 2a. The body section 2a of the housing 2 is manufactured by integral molding of a synthetic resin material together with the handle section 2b and the battery attachment section 2c, and is configured to be divided into two parts, left and right, by a vertical plane passing through the rotating shaft 4 of the motor 3. In assembling, the motor, the reduction mechanism, the impact mechanism, etc. are installed in one of the housings 2 (for example, the left housing), and then the other housing 2 (for example, the right housing) is placed on top of the housing and fastened to the screw bosses of the housings with a plurality of screws 29a to 29h. A trigger lever 7a is disposed at the upper part of the handle section 2b so as to protrude forward, and a forward / reverse switching lever 8 for switching the rotation direction of the output shaft 10 between forward and reverse is provided on the rear side of the trigger lever 7a. A battery attachment section 2c is formed to extend horizontally at the lower end (end opposite to the body section) of the end of the handle section 2b located opposite to the body section 2a, and a battery 300 consisting of a secondary battery such as a lithium ion battery is detachably attached thereto. 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 the left and right 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 illumination device 9 using LEDs is provided below the front end of the hammer case 5.

[0019] The battery attachment section 2c is provided with a rail mechanism and a group of connection terminals for mounting the battery 300, and also accommodates a control circuit board (described later in FIG. 2) therein. The width of the battery attachment section 2c is approximately the same as that of the upper surface of the battery 300. A first switch panel 46 is provided on the upper surface of the battery attachment section 2c, in a portion forward of the lower end of the handle section 2b. The first switch panel 46 is provided with a light switch for turning on the illumination device 9 for illuminating an object to be fastened by the tip tool, a battery remaining amount display switch and a battery remaining amount display lamp for displaying the remaining amount of the battery 300, and a strength display lamp for displaying the strength of impact. A second switch panel (not shown) is also provided on the left side surface of the battery attachment section 2c, and a strength / weakness changeover switch (not shown) for adjusting the strength of impact (strength of fastening) is provided.

[0020] FIG. 2 is a vertical cross-sectional view showing the internal structure of the electric power tool 1 of this embodiment. The motor 3 is accommodated in a cylindrical body 2a of the housing 2, which is substantially T-shaped in side view. The motor 3 is a DC (direct current) motor without brushes (commutation brushes), and is a 4-pole, 6-slot brushless DC motor. The motor 3 includes a rotor 3a with a permanent magnet and a stator 3b with a multi-phase armature winding (stator winding) such as a three-phase winding. The motor 3 is operated by switching a DC voltage supplied from a battery or the like by a plurality of semiconductor switching elements 14 using the output of a position detection element 13 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 arranged concentrically with the axis A1 of the cylindrical body 2a, and is journaled to the housing 2 by two bearings 16a, 16b at the front and rear sides. A substantially annular inverter circuit board 12 for mounting three position detection elements 13, six semiconductor switching elements 14, etc. is disposed on the rear side of the stator 3b. The inverter circuit board 12 is a substantially annular double-sided board with a diameter almost the same as the outer diameter of the motor 3. Six semiconductor switching elements 14 are provided to form an inverter circuit, which switches the current supply to the stator windings of each phase. As the semiconductor switching elements 14, FETs (field effect transistors), IGBTs (insulated gate bipolar transistors), etc. are used. The inverter circuit is controlled by a microcomputer, which sets the current supply timing of the armature windings of each phase based on the position detection results of the rotor 3a by the position detection elements 13, making it easy to perform advanced rotation control.

[0021] The hammer case 5, which accommodates the reduction gear mechanism 20 and the impact mechanism 21, 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 corresponding 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] Between the rotor 3a and the bearing 16a, a rotor fan 15 is attached coaxially with the rotary shaft 4. The rotor fan 15 is integrally molded, for example, by plastic molding, and is a so-called centrifugal fan that sucks in 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 part 2a through the air intake 17a and the air intake 17b (see FIG. 1) formed in the housing part 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 a slit-shaped air discharge port 17c (see FIG. 1) to be described later that is formed in the housing part around the rotor fan 15.

[0023] The rotor 3a forms a magnetic path formed by a permanent magnet. The stator 3b is manufactured with a laminated structure of thin iron plates in an annular shape, and six teeth (not shown) are formed on the inner circumference, and enameled wire is 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 a portion to be held by the operator, and is substantially cylindrical along the axis B1, and has a shape suitable for holding 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 side 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 vicinity 43a to 43d of the base of the connection portion is reinforced.

[0025] The battery attachment section 2c of the housing 2 has a portion that protrudes forward and left and right from a position on the extension of the handle section 2b, and accommodates a control circuit section 30 including a control circuit board 31 (described later in FIG. 3) having a function of controlling the speed of the motor 3 by pulling the trigger lever 7a. The control circuit section 30 is electrically connected to the battery 300 and the trigger switch 7 by a plurality of lead wires. The control circuit board 31 is also provided with a connector (not shown) for connecting the control circuit board 31 to the lead wires (not shown). The control circuit board 31 is further electrically connected to the inverter circuit board 12 through a plurality of lead wires. An input / output operation section for performing input operations and display operations using LEDs or the like is provided near the control circuit board 31 and on the upper surface of the battery attachment section 2c. Here, a separate switch panel 46 provided on the housing 2 is provided as the input / output operation section, and a switch for checking the remaining charge of the battery 300, an LED display device for displaying the remaining charge, and a switch for turning on the illumination device 9 are arranged on the panel (described later in detail in FIG. 8). The switch panel 46 is fixed firmly or loosely to the control circuit section 30 side, and is held so as to be sandwiched from 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 section 2c. The battery mounting section 2c corresponds to a housing section that houses a 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, and is rotatably supported at its rear end by the bearing 18b and at its front end by the bearing 18a. The reduction mechanism 20 and the impact mechanism 21 constitute a power transmission mechanism for driving the tool tip by the motor 3. When the trigger lever 7a is pulled to start the motor 3, the motor 3 starts to rotate in the direction set by the forward / reverse switching lever 8, and the rotational force is reduced by the reduction mechanism 20 and transmitted to the spindle 22, so that the spindle 22 is rotated at a predetermined speed. The spindle 22 and the hammer 24 are connected by a cam mechanism, and this cam mechanism 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 these spindle cam grooves 23 and 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 between the steel ball 26 and the spindle cam grooves 23, 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 makes a half rotation, causing the anvil 28 to rotate, but when a relative rotation occurs between the spindle 22 and the hammer 24 due to the engagement reaction force at that time, the hammer 24 starts to move backward toward the motor 3 while compressing the hammer spring 27 along the spindle cam groove 23 of the cam mechanism. Then, when the protrusion of the hammer 24 overcomes the protrusion of the anvil 28 due to the backward movement of the hammer 24 and the engagement between them is released, the hammer 24 is rapidly accelerated in the rotational direction and forward by the action of the cam mechanism and the elastic energy stored in the hammer spring 27 in addition to the rotational force of the spindle 22, and moves forward by the biasing force of the hammer spring 27, and the protrusion engages with the protrusion of the anvil 28 again and starts to rotate together with it. At this time, a strong rotary impact force is applied to the anvil 28, which is transmitted to the screw via the tool tip (not shown) that is attached to the mounting hole 10a of the anvil 28. Thereafter, the same operation is repeated, and the rotary impact force is intermittently and repeatedly transmitted from the tool tip to the screw, and the screw is screwed into a member to be fastened (not shown), such as wood.

[0028] 3A is a partially enlarged cross-sectional view of the battery attachment portion 2c in FIG. 2. The battery attachment portion 2c constitutes an attachment portion for attaching the battery 300, and is a portion for holding a terminal holder 50 on which a terminal on the tool side for connecting to a terminal on the battery 300 side (battery side terminal) is provided, and further functions as a housing portion for housing the control circuit portion 30. The control circuit portion 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 on the top side, and the inside of the board case 35 is filled with a 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 the board case 35 in a liquid state and hardened, and a hardening resin such as urethane is used for the resin 33. Here, the resin 33 is poured up to the upper end opening of the board case 35, and then hardened, so that the upper surface (liquid level) of the resin 33 becomes almost the same as the upper end position of the board case 35, and the part of the control circuit board 31 located inside the board case 35 is completely immersed. The hardening resin used here should have elasticity that allows a certain degree of deformation when subjected to a load caused by external pressure, but any type of hardening resin can be used, and it may be not only one that has elasticity after hardening, but also one that becomes hard after hardening and has weak or almost no elasticity. The board case 35 is formed by integral molding of a synthetic resin such as plastic, and small protrusions 35a and 35b that protrude in the left and right directions are formed on a part of the outer surface of the board case 35, on the side in the direction in which the housing 2 is divided (left and right direction), and further a protrusion 35c that protrudes forward from the front side is formed. The protrusion 35c has a sufficient length that continues in the left and right direction. Further, 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 formed on the inner side wall portion of the housing 2. The board case 35 is sandwiched by 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 stably held by 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 absorb impacts during collisions, to improve the feel when the operator grips the housing, and to provide a non-slip effect. The soft layer 6 is, for example, elastomer, and is formed into a two-layer structure so as to cover the entire surface during injection molding of the housing 2 made of synthetic resin. A beam member 40 is provided on the lower side of the board case 35, extending in the left-right direction and having a flat upper surface. The beam member 40 is provided so as to contact the bottom surface 35d of the board case 35, and is provided at a position contacting the bottom surface slightly forward of the center when viewed in the front-rear direction. The beam member 40 is a hollow rectangular column, and is configured to continue from the right side surface to the left side surface of the battery attachment portion 2c of the housing 2. The beam member 40 is made of synthetic resin like the housing 2, and is molded integrally with the housing 2. A terminal holder 50 is provided on the lower side of the beam member 40, which is rearward and faces the control circuit unit 30 in the up-down direction. The 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 the battery 300 (see FIG. 2), and has a recess 51a formed on the front side edge and a recess 51b formed on the rear side edge, which are fitted into protrusions formed on the housing 2 to be attached to the underside of the battery attachment section 2c. The battery attachment section 2c further has a rail groove 52-2 and a rail section 53-2, and a latch groove 54-2 formed near the front end of the rail section 53-2.

[0030] FIG. 3(B) is a model showing the position where the load is applied and the degree of deformation of the control circuit section 30, and shows the position of the maximum deformation point of the housing as viewed in the front-rear direction and the positional relationship with the beam member 40 serving as the support section (when stationary). The shape of the control circuit section 30 is simplified and shown 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 section 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 down. 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 shown by the arrow in FIG. 3(A). Here, the deformable portion 34 of the housing 2 is located at a position separated from the control circuit section 30 by a gap as shown in FIG. 3(B) when no impact is applied, but at the moment when the power tool 1 is dropped in an upright position and hits the floor, a strong load 36A is applied to the portion 34 via the handle section 2b, causing the portion 34 to move downward (deform) and hit the control circuit section 30. However, in this embodiment, the beam member 40 extending in the left-right direction is located on the opposite side of the board case 35 with respect to the direction in which the load 36A is applied, so that the force of the control circuit section 30 that is about to deform is supported from below by the beam member 40 as shown by the force of the arrow 41. The portion 34 is located above the control circuit section 30 and faces the control circuit section 30 (which holds the control circuit board 31 via the resin 33). The opening 45 is also located above the control circuit section 30 and faces the control circuit section 30.

[0031] Here, for comparison, the shape of the housing 202 of the 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 portion 30 is the same part 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 on the upper side of the front side of the control circuit portion 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, 239b (however, 239a is not visible in the figure) extending in parallel in the vertical direction are formed on the inner side wall portion of the housing 2 near the rear side of the board case 35 so as to abut the left and right sides. FIG. 18(B) is a diagram showing the position (at rest) of the maximum deformation part (specific part 234) of the housing 202 as viewed in the front-rear direction, and FIG. 18(C) is a diagram showing the positional relationship between the position of the maximum deformation part of the housing 202 as viewed in the front-rear direction and the support part (when an impact occurs). As viewed in the front-rear direction, the control circuit part 30 is held by the front recess 238c and the rear ribs 239a, 239b. Also, the specific part 234 is located between the front recess 238c and the rear ribs 239a, 239b. Here, when a downward force in the direction of the arrow 236 acts on the specific part 234 due to the impact tool being dropped, etc., the specific part 234 deforms and comes into contact with the control circuit part 30, and the control circuit part 30 bends downward with the recess 238c and the rear ribs 239a, 239b as fulcrums. At this time, upward forces 240a, 240b act from the ribs 239a, 239b against the downward force 236. Returning to Figure 3, as is apparent 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 in the vertical direction with the maximum deformation point (specific portion 234) of the housing 202, so that deformation of the control circuit section 30 can be effectively suppressed.

[0032] Fig. 4(A) is a cross-sectional view of the AA portion in Fig. 3, and shows the shape of the housing 2 of this embodiment. The left and right sides of the container-shaped board case 35 are wall surfaces, and two protrusions 35a and 35b are formed at the top so as to protrude horizontally. The board case 35 is open on the side (first surface) facing the part 34 of the control circuit board 31 described later, and covers the surface (second surface) located opposite the first surface. Since the AA cross section position in Fig. 3(A) 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, but as can be seen by comparing the position of the AA line in Fig. 3(A), 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-rear direction is not comparable to the length of the board case 35, and the protrusions 35a, 35b are formed only partially on the front side as shown by the dotted line in Fig. 3(A). This is because the weight of the control circuit board 31 is smaller than the other components (motor 3, power transmission mechanism, battery 300), and so it does not require much strength unless it is subjected to an excessive impact from being dropped. Here, the beam member 40 is formed so as to be located at one location that coincides with the deformed portion 34 when viewed in the first direction (front-rear direction) of the control circuit section 30 (or control circuit board 31).

[0033] For comparison, the shape of the housing 202 of a conventional impact tool will be described with reference to FIG. 19. FIG. 19 is a cross-sectional view of the HH portion of FIG. 18. In this example, the beam member 40 is not formed on the lower side of the board case 35, so the ribs 238a and 238b for holding the protrusions 35a and 35b are formed on the housing 202. On the other hand, the lower side of the bottom surface 35d of the board case 35 is a gap. FIG. 19(B) is a diagram showing the position of the maximum deformation part (specific part 234) of the housing 202 viewed from the left and right and the positional relationship (at rest) of the ribs 238a and 238b that hold the protrusions 35a and 35b, and FIG. 19(C) is a diagram showing the position of the maximum deformation part of the housing viewed from the left and right and the positional relationship (at impact) of the ribs 238a and 238b. As can be seen from this figure, when a strong force is applied to the specific part 234 in the direction indicated by the arrow 236, the control circuit part 30 bends downward. At this time, the portions receiving the force of the arrow 236 are the left and right ends, and the points of action thereof are 141a and 141b.

[0034] FIG. 4(B) is a diagram showing the position of the maximum deformation part of the housing 2 in the left-right direction and the positional relationship (at rest) between the beam member 40 as a support part. The beam member 40 is composed of a right beam member 40-1 molded integrally with the right part of the housing 2 and a left beam member 40-2 molded integrally with the left part of the housing 2, and the contact parts of the right beam member 40-1 and the left beam member 40-2 are formed so that one side is concave and the other side is convex, and are configured so that the concave part and the convex part fit together when joined. The beam members 40-1 and 40-2 contact the bottom surface 35d of the board case 35 so as to be continuous in the left-right direction. This state is shown in FIG. 4(B), and when the power tool is at rest (not in a state where it has been dropped and impacted), the specific part 34 that is easily deformed is in a non-contact state with the control circuit part 30 with a predetermined gap. At the moment when the power tool 1 is dropped in an upright position and hits the floor, as shown in FIG. 4(C), a strong load 36A applied via the handle portion 2b moves a specific portion 34 downward and contacts the control circuit unit 30. However, in this embodiment, the beam member 40 extending in the left-right direction is located on the extension line of the position where the load 36A is applied and on the opposite side of the board case 35, so that the beam member 40 (40-1 and 40-2) supports the control circuit unit 30, which is about to be deformed, from below in the direction of the force of the arrow 41A. Here, the beam member 40 (40-1 and 40-2) is formed to be located on the entire left and right including the portion 34 to be deformed when viewed in the second direction (left-right direction) of the control circuit unit 30 (or the control circuit board 31). By providing the beam member 40 in this manner, it is possible to effectively prevent the control circuit board 31 from being deformed due to an excessive load applied to the control circuit board 31 of the control circuit unit 30. In particular, when comparing the degree of bending of the control circuit section 30 in FIG. 4(C) with the degree of bending of the control circuit section 30 in FIG. 19(C), it will be understood that the structure shown in FIG. 4 causes significantly less bending to the control circuit board 31.

[0035] FIG. 5 is a perspective cross-sectional view taken from the BB portion of FIG. 3. At this cross-sectional position, no protrusions are formed on either the left or right side of the board case 35. A microcomputer and other electronic components are actually mounted on the control circuit board 31, but these are not shown. The left and right sides of the board case 35 are held by wall portions 37 so that the board case 35 does not wobble in the left-right direction. Beam members 40 (40-1, 40-2) are provided on the lower side of the board case 35. The beam member 40 is formed in a cylindrical shape that is hollow in the longitudinal direction and in the cross-sectional shape, but may be a solid beam portion instead of hollow. 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, so that the strength is sufficiently high. The upper surface of the battery 300 is located below the beam member 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 sides of the rail portions 53-1 and 53-2.

[0036] An opening 45 is formed on the upper surface of the battery attachment portion 2c so as to intersect with the joint surface of the battery attachment portions 2c-1 and 2c-2. The opening 45 is formed to provide a switch panel 46 (see FIG. 1), and is disposed near the front side of the base of the handle portion 2b (2b-1, 2b-2) of the housing 2. If the opening 45 is provided near the base 43d of the handle portion 2b (2b-1 and 2b-2) and the battery attachment portion 2c (2c-1, 2c-2) in this manner, the strength of the portion (specific portion 34) close to the base 43d of the opening 45 is reduced compared to other portions. When the power tool 1 falls in an upright position and hits the floor, the battery 300 often hits the floor first, and at that time, the weight of the falling heavy object such as the motor 3 and the power transmission mechanism is applied to the battery attachment portion 2c via the handle portion 2b, so that the specific portion 34 is deformed 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 as in FIG. 3(A), showing the state when an impact is applied by dropping the battery mounting portion 2c in an upright state. In the case where the handle portion 2b is formed extending upward perpendicularly from the horizontally extending portion of the battery mounting portion 2c as in this embodiment, and an opening 45 for the switch panel 46 (see FIG. 1) is formed on the upper surface of the extension portion, a specific portion 34 is deformed by being pushed downward when it receives an impact from a drop. This is because the battery mounting portion 2c of the housing 2 has a large opening 45, and the portion of the opening 45 that is closest to the portion to which the impact from the handle portion 2b is transmitted and is weak in strength is deformed the most. As a result, the central rear side edge of the opening 45 is deformed and sinks downward as shown by 34c in FIG. 6, and the portion 34 is pushed into the resin 33. When the battery mounting portion 34 is deformed in this manner, a force is applied to bend the control circuit portion 30 downward. The forces acting on the control circuit board 31 include compressive stress and bending stress, but bending stress is 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 close to the center of the control circuit board 31. Therefore, if the portion close to the center of the control circuit board 31 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 and directly below the specific portion 34, so that even if stress is applied to the specific portion 34, deformation that bends the control circuit section 30 is suppressed, and therefore damage to electronic components mounted on the control circuit board 31 caused by bending the control circuit board 31 can be effectively suppressed.

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

[0039] FIG. 8 is a top view showing the extension of the battery attachment portion 2c, and is a diagram showing the switch panel 46. The outer edge shape near the base of the handle portion 2b is approximately circular, and an extension is formed that extends in a plane from the base to the front side, the right side, and the left side. The switch panel 46 is disposed approximately near the center of the extension that extends forward. The switch panel 46 is disposed in an opening 45 formed in the housing 2, and it is advantageous in terms of wiring and assembly if the board case 35 that houses the control circuit board 31 is disposed directly below the opening 45. The switch panel 46 is made of synthetic resin, and is provided with switches and lighting means using soft touch switches. The light switch 47 is a switch that sets the irradiation mode of the lighting device 9, and there are a continuous irradiation mode that turns on the light for a certain period of time (for example, 2 minutes) regardless of whether the trigger lever 7a is operated or not, and a switch-linked irradiation mode that turns on the light when the trigger lever 7a is operated and turns off in a short period of time (for example, 10 seconds) when the trigger lever 7a is released. Each time the light switch 47 is pressed, the mode is switched from continuous irradiation mode to switch-linked irradiation mode to off. In the continuous irradiation mode, the LED 48a is on, and in the switch-linked irradiation mode, the LED 48b is on, and when the lighting device 9 is off, neither the LED 48a nor the LED 48b is on. On the right side of the switch panel 46, only a logo is displayed here, and no other switches are provided. However, a switch and multiple LEDs for checking the remaining battery level may be provided, or a tightening mode switching switch and multiple LEDs for switching the tightening mode may be provided. The switch panel 46 is manufactured as a separate part 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 FIG. 8, the area surrounded by an ellipse is the specific portion 34 that is easily deformed by the impact when dropped. The position where the beam member 40 is provided is the position shown by the dotted line. When the specific portion 34 is seen through from above in FIG. 8, it can be understood that the specific portion 34 is in a positional relationship that is included in the internal region of the beam member 40. In addition, the region occupied by the beam member 40 shown by the dotted rectangular line is positioned so as to partially overlap the region occupied by the switch panel 46, so that it not only serves as a measure against the impact when dropped on the specific portion 34, but also effectively counters the weight that tends to deform the control circuit board 31 due to the influence of the pressing force applied to the switch panel 46 on the control circuit unit 30 when the switch panel 46 is operated. In this way, when a part of the housing 2, particularly the specific portion 34, is deformed when the product is dropped, it is possible to prevent the control circuit board 31 from being pushed in and damaged by the housing 2.

[0041] As described above, in this embodiment, the beam member 40 is formed on the inside of the battery attachment portion 2c of the housing 2, extending in a direction perpendicular to the dividing surface, and holds 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 the control circuit board 31 being damaged when the power tool 1 is accidentally dropped. In addition, the beam member 40 can be formed simply by changing the injection molding mold of the housing 2, and the control circuit board 31 and the board case 35 can be kept in their conventional shapes, so that the present invention is easily applicable. In particular, this is 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 (housing portion) that protrudes radially from the handle portion 2b, that is, 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, in a configuration in which the control circuit unit 30 is housed (supported) only in the protruding portion, there is little risk of the control circuit unit 30 being bent even if it is pushed by the portion 34. EXAMPLES

[0042] FIG. 9 is a partially enlarged cross-sectional view of the vicinity of the control circuit board 61 of the housing 2 according to the second embodiment of the present invention. The second embodiment has the same structure as the first embodiment in that the beam member 40 is formed on the housing 2, but in addition to forming the beam member 40, a column portion 65e is formed on a part of the board case 65, extending upward from the bottom surface 65d (the second surface side of the control circuit board 61). The column portion 65e is formed directly below a specific portion 34 that is easily deformed by the impact of a fall, and a cylindrical or rectangular columnar member extends upward to the vicinity of the specific portion 34 so as to penetrate the control circuit board 61. The height of the column portion 65e is set to the same position or approximately the same position as the upper opening surface of the board case 65. The column portion 65e is formed by integral molding of synthetic resin, which is a non-conductor, like the board case 65. The shape and configuration of the column portion 65e of the board case 65 are the same as those of the board case 35 of the first embodiment, except that the through hole 61a is provided. Convex portions 65a, 65b (65a is not visible in FIG. 9) are formed on both the left and right sides of the front, and a convex portion 65c is formed on the front edge portion. In addition, a through hole 61a is formed in the control circuit board 61 to allow the pillar portion 65e to penetrate vertically. The shape of the through hole 61a is preferably an appropriate size for positioning the control circuit board 61 in the board case 65 while allowing the pillar portion 65e to penetrate, and here, the gap between the through hole 61a and the pillar portion 65e is almost zero, but a gap may be present. The periphery of the control circuit board 61 accommodated in the board case 35 is filled with a hardening resin 63. The hardening resin is a material that does not conduct electricity, and is a smooth liquid when filled in the board case 35, so that it can be filled into every corner of the inside of the board case 35 without any gaps. The pillar portion 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 a specific portion 34 is about to deform due to an impact when dropped as shown in Figures 6 and 7, the portion 34 comes into contact with the upper surface of the pillar portion 65e. The pillar portion 65e is a member extending in the vertical direction, and the beam member 40 for receiving the load during the impact is provided on the lower side of the board case 65 on the extension of its longitudinal axis. In particular, when viewed in a cross-sectional view such as Figure 9, the portion 34, the pillar portion 65e, and the beam member 40 are arranged so as to be aligned in the vertical direction, so that the load that is about to deform due to the impact can be firmly received by the pillar portion 65e and the beam member 40, and it is possible to prevent the application of a strong bending force or compressive force to the control circuit board 61. EXAMPLES

[0044] 10 is a partially enlarged cross-sectional view of the vicinity of the control circuit section 70 of the housing 2 according to the 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 board case 75. The reinforcing member 76 is made of a highly rigid member such as a long and thin iron plate or stainless steel plate that is pressed to increase its strength and then projected so as to be continuous in the longitudinal direction.

[0045] FIG. 11 is a cross-sectional view of the DD portion of FIG. 10. Recesses 75e and 75f are formed at two locations on the opening edge of the substrate case 75, and both ends of the reinforcing member 76 are positioned in the recesses 75e and 75f. When a deforming load is applied downward from a specific portion 34 near the center of the reinforcing member 76, the deforming portion comes into contact with the center portion 76a of the reinforcing member 76, so that the deforming load can be effectively prevented from being directly applied to the control circuit board 31. The material of the reinforcing member 76 is not limited to metal such as iron, but may be made of a resin member having high bending rigidity such as carbon or other high strength material. In addition, one or more rods may be used instead of a plate material. The reinforcing member 76 is appropriately positioned in the recesses 75e and 75f after the control circuit board 31 with the components mounted thereon is accommodated inside the substrate case 75, and the hardening resin 73 is poured into the substrate case 75 so as to fill the substrate case 75 up to the portion excluding the upper surface of the reinforcing member 76. Since the curable resin 73 also has adhesive properties, the reinforcing member 76 is stably held by the cured resin 73 without rattling.

[0046] 10, the housing 2 is formed with the beam member 40 of this embodiment, but it is also possible to add only the reinforcing member 76 of the third embodiment to a conventional housing 202 (see FIGS. 18 and 19) that does not have the beam member 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. EXAMPLES

[0047] 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 almost 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 sufficiently secure a gap 237 below the specific portion 234, so that even if the specific portion 234 is deformed as shown in FIGS. 6 and 7 due to the impact of the drop, the deformed portion does not come into contact with the control circuit section 30, or the force applied even if it does come into contact is not large. By providing such a gap, even if the stress caused by the deformation of the specific portion 234 is not directly transmitted to the control circuit section 30, the control circuit board 31 can be prevented from being damaged by the impact of the drop.

[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, this only needs to be applied when the design of the housing 202 is changed, so it can 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 portions 30, 60, and 70 of the first to third embodiments, rather than being used alone. EXAMPLES

[0049] 14 is a partially enlarged cross-sectional view of the control circuit section 80 of the housing 2B according to the fifth embodiment of the present invention. In the fifth embodiment, the control circuit section 80 is substantially the same as that used in the first embodiment, but the beam member 40 is not formed on the housing 2B side, but is formed integrally with the terminal holder 55 side. In addition, since the terminal holder 55 is configured to receive the load during impact, the mounting rigidity of the terminal holder 55 to the housing 2B is significantly increased. In addition, a plurality of ribs 86a, 86b, 87a, 87b for firmly holding the terminal holder 55 are provided on the inner wall side of the battery mounting portion of the housing 2B. The terminal holder 55 is a member for fixing a plurality of terminals 57a, 57b, etc. that are engaged with the connection terminals of the battery 300, and is manufactured by casting a metal plate-shaped member (terminals 57i, 57g, etc.) into the base portion 56 in a non-conductor such as synthetic resin. When the battery 300 is attached and detached, a strong force is applied to the terminal holder 55 in the front-rear direction, so that the front edge (projection 55c) of the terminal holder 55 is sandwiched and held by a set of ribs 86a, 86b extending continuously and parallel to the left and right direction, and the rear edge (projection 55d) of the terminal holder 55 is sandwiched and held by a set of ribs 87a, 87b extending continuously and parallel to the left and right direction. In addition, abutment rib 55f is formed on the lower rear side of the terminal holder 55, and is abutted against a rib 87c on the inner wall of the housing 2B. A support portion 58 is formed on the upper surface side of the terminal holder 55, protruding upward. The support portion 58 has the same function as the beam member 40, and when an impact is applied to a specific portion 234 during a drop, the support portion 58 can receive the weight applied to the control circuit portion 80. In the fifth embodiment, the shape of the terminal holder 55 is changed to realize the power tool 1 that is provided with a measure against impact during a drop.

[0050] FIG. 15 is a cross-sectional view of the FF portion in FIG. 14. The terminal holder 55 has a total of nine terminals 57a to 57i provided on the base. The terminals 57a and 57b are positive terminals for discharging. The 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). The terminal 57d is a T terminal for outputting a signal serving as identification information of the battery 300 to the power tool body or the charging device. The terminal 57e is a V terminal for inputting a control signal from an external charging device (not shown). The 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. The terminals 57g and 57h are negative terminals (- terminals). The 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 contacts the lower surface of the board case 85. The support portion 58 is a convex portion extending continuously in the left-right direction, and the left-right length of the support portion 58 is longer than the left-right length of the board case 85. EXAMPLES

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

[0052] Fig. 17 is a cross-sectional view of the GG portion in Fig. 16. As shown in this figure, a total of nine terminals 57a to 57i are provided on the base portion 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 cross section, the protrusion 95f and the lower surface of the terminal holder 55A come into contact with each other. 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 attachment portion 2c (a housing portion that houses the board). EXAMPLES

[0053] FIG. 20 is a perspective view of a control circuit unit 130 of an electric power tool 101 according to a seventh embodiment of the present invention. The control circuit unit 130 is configured such that a control circuit board 131 on which a microcomputer (not shown), other electronic elements, connectors, and other electronic components are mounted is housed inside a board case 135, which is a dish-shaped container with an opening at the top, and a switch panel 150 is provided on the front side of the board case 135. The components mounted inside the board case 135 are basically the same as those in the first embodiment. The outer edge shape of the board case 135 is basically a rectangle when viewed from above as in the conventional case, but is a shape (octagonal) in which each corner is cut off obliquely. The board case 135 is in the shape of a tray or container having an opening surface 136 on the top side, and is shaped so that liquid will not leak even if it is filled inside. The control circuit board 131 has an outer edge shape that conforms to the inner wall shape of the board case 135, and the control circuit board 131 is held inside the housing 102 by sandwiching the board case 135 between the right and left parts 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 divided 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 hardened. In the first embodiment, the entire outer edge of the control circuit board 131 is fixed at a step portion 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 part 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 portion exposed to the outside from an opening 104 (see FIG. 22 described later) of the housing 102, 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 a wall portion that is in close contact with the inner wall surface of the board case 135 and a portion (rib 154, flat plate portion 155) that abuts against the control circuit board 131 by extending downward from the main portion. The switch panel 150 has a flat upper surface 151 formed 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 in FIG. 20. In the seventh embodiment, the method of fixing the control circuit board 131 to the board case 135 is different from that in the first embodiment. As in the second embodiment shown in FIG. 9, the board case 135 is formed with a support portion (protruding portion 138) that penetrates the through hole of the control circuit board 131 and extends upward. The shape of the board case 135 in a top view is almost the same as the outer edge shape of the control circuit board 131, and is a tray-like or dish-like container having an opening surface 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 provided slightly forward of the center position in a top view.

[0056] A circular step portion 138b is formed near the center of the raised portion 138 in the vertical direction, and a cylindrical portion 138c is formed on the inner periphery of the step portion 138b so as to extend upward from the step portion 138b. The cone portion 138a below the step portion 138b is cone-shaped, and is shaped so that the diameter increases from top to bottom, and is connected to the bottom surface 134. By making the cone portion 138a funnel-shaped, the stress applied from top to bottom is reduced. The shape of the cone portion 138a is arbitrary, and as long as the step portion 138b can hold the substrate, the shape of the cone portion 138a is arbitrary. The upper end of the cylindrical portion 138c becomes a small circular surface 138d, and a thin non-through hole for a screw is formed in the center. A screw 141 is screwed into the inner hole of the cylindrical portion 138c and is tightened until the bottom surface of the head of the screw 141 abuts against the circular surface 138d. If a metal tapping screw is used as the screw 141, even if a female thread is not formed beforehand inside the cylindrical portion 138c, the screw can be threaded into the cylindrical portion 138c while tapping itself as long as there is a pilot hole.

[0057] The switch panel 150 is formed to have the same width as the board case 135, and its front position is approximately the same as the front wall of the board case 135. The right and left edges of the switch panel 150 are formed in a stepped shape, and the stepped portions abut against the outer edge of the opening surface 136 of the board case 135, and ribs 153a and 153b are formed below the stepped portions. A rib 153c is also formed in the center of the lower front edge of the switch panel 150, extending downward, and the bottom surfaces of these ribs 153a, 153b, and 153c abut against the control circuit board 131, and play a role in keeping 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, and this makes it possible to keep the openings 152a and 152b and the plungers 161a and 162a horizontal. On the other hand, the switch panel 150 and the board case 135 are positioned by the contact surfaces of the outer peripheries of the ribs 153a, 153b, and 153c with the board case 135 and the through holes 156 through which the screws 141 penetrate. 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 flat plate portion 155 extends rearward from the rib 154 in a tab-like shape, and a through hole 156 is formed in the center of the flat plate portion 155. The control circuit board 131, the lower portion of the switch panel 150, the rib 154, and the flat plate portion 155 are each joined to the board case 135 with a hardening resin. The through hole 156 is large enough to allow the cylindrical portion 138c of the raised portion 138 to penetrate through the through hole 156.

[0058] The upper surface 151 of the switch panel 150 is formed with two openings 152a and 152b to form a pressing surface for pressing the plungers 161a and 162a of the switches 161 and 162. An elastic resin film (not shown) is provided on the entire upper surface 151 including the two openings 152a and 152b, and a button display showing the pressing positions of the switches 161 and 162, a transparent window for the LED, and the like are printed on the film. In the portion sandwiched between the openings 152a and 152b of the switch panel 150, five rectangular through holes 152c in a top view and two circular through holes 152d are arranged to transmit light from the LEDs (not shown) mounted on the control circuit board 131.

[0059] The switches 161 and 162 are, for example, tactile switches. The plungers 161a and 162a are pressed in by an operator (push operation) to turn on the switch 161 or 162. The plungers 161a and 162a are biased upward by a spring, i.e., to a state in which the switch is turned off, so that the switch performs a "momentary action" in which the switch is turned on when the plungers 161a and 162a are pressed in and turned off when the pressed state is released. A plurality of terminals (for example, four terminals) not shown protrude from the lower side 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, 132b and two rectangular cutouts 132c, 132d are formed in the control circuit board 131. The through hole 132a is for determining the vertical position of the control circuit board 131 by abutting against a step portion of a support portion (raised portion 138) described later. The through hole 132a is a hole for passing a screw 142 through. The cutout portions 132c, 132d are formed to pass a cable or the like from the lower surface side to the upper side, but if there is no need to pass a cable or the like through, the cutout portions 132c, 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 surface. The step 137 is nearly 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 of the parallel right sides of the control circuit board 131. Therefore, no support portion is formed in the vicinity of the right and left edges of the control circuit board 131 in the downward direction. The screw 142 is screwed into the board case 135 by penetrating the through hole 132b. However, a small cylindrical screw boss 139 (not shown in the figure) described later is formed in the lower part of the through hole 132b.

[0062] FIG. 22 is a perspective view showing the mounting state of the control circuit unit 130 in FIG. 20 to the housing 102. Here, only the right side of the housing 102 is shown, and the left side of the housing 102 is not shown. The board case 135 is sandwiched between the left and right housings 102 so as to be fitted into beams and recesses formed on the inner sidewall of the housing 102. An opening 120 for fixing the terminal holder 50 (see FIG. 3) is formed on the lower side of the board case 135. As can be seen from this figure, the screw 141 is located at a position passing through the vertical dividing plane of the housing 102 and is located directly below the specific portion 104 that is most likely to be deformed by the impact of a drop. Moreover, the lower surface of the specific portion 104 and the screw 141 are kept in a non-contact state 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 attachment portion 102c of the housing 102. Although the film 160 provided on the switch panel 150 is not shown in FIG. 22, dust and water can be prevented from reaching the control circuit board 131 by covering the entire upper surface 151 with the film 160.

[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 vertical cross-sectional view based on the left and right dividing plane of the housing 102. The board case 135 is arranged perpendicular to the dividing plane of the left and right dividing housing 102, and is fixed by being sandwiched between the right and left housings 102. The front lower side of the board case 135 is held by a holding surface 121a formed on the inner wall portion of the housing 102. In addition, a rib 122 extending in the up, down, left and right directions is formed in the approximate center of the board case 135 in the front-rear direction. The rib 122 is arranged in the vicinity of the location where local deformation of the housing occurs when it is dropped, that is, in the vicinity of the installation position of the screw 141. Here, the positional relationship is such that the downward projection range of the raised portion 138 partially overlaps with the installation range of the rib 122 when viewed from above. With this positional relationship, the impact applied from above to below the raised portion 138 can be effectively received by the rib 122 acting as a beam portion. Incidentally, the rib 122 also serves as a member forming part of the front edge of the opening 120 formed in the housing 102 for mounting the terminal holder 50 (see FIG. 3). The upper rear part and the lower rear part of the board case 135 are not held by the ribs 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 occurring 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 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 only by the raised portion 138 and harden it with hardening resin. However, in an electric tool, not only an unexpected heavy load caused by a drop impact but also vibrations applied during operation are transmitted to the control circuit board 131. Therefore, in order to prevent the control circuit board 131 from moving downward relative to the board case 135, the lower front edge of the control circuit board 131 is held by a stepped portion 137 formed on the board case 135. Furthermore, by fixing the rear end side of the control circuit board 131 with a screw 142, it is possible to prevent the control circuit board 131 from being distorted and tilted when the hardening resin is filled inside the case. 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 in the vertical direction when the switch panel 150 is operated.

[0066] A screw boss 139 is formed in the center of the rear of the board case 135, and the control circuit board 131 is screwed in by screwing a screw 142 into the screw boss 139. The screw boss 139 is a cylindrical member that is formed integrally 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. No member that abuts against the lower surface of the control circuit board 131 is formed on either side of the screw boss 139. It is preferable that the screw boss 139 is located in the center of the left and right so as to be on the dividing surface of the housing 102. However, the position of the screw 142 does not need to be strict, and there is no problem even if it is slightly shifted in the horizontal direction from the dividing surface. In FIG. 23(A), the screw boss 139 is located near the inner rear end of the board case 135, but the screw boss 139 may be located slightly forward of the rear end.

[0067] A switch panel 150 is provided on the front upper side of the board case 135. The operation surface buttons are printed on the upper 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 mounting the terminal holder 50 (see FIG. 3), 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, etc. Through hole 132a formed in the approximate center of control circuit board 131 is a hole that is sufficiently larger than not only screw 141 but also cylindrical portion 138c (see FIG. 21 for the symbol) of protruding portion 138. Therefore, the vicinity of the center of control circuit board 131 is not restricted in the up-down direction by screw 141. In addition, since the curable resin covering the entire control circuit board 131 has a certain degree of elasticity, control circuit board 131 can move slightly relative to protruding portion 138.

[0070] FIG. 24 is a diagram of the board case 135 of the seventh embodiment, where (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). The inner portion of the board case 135 is formed with three holding portions for holding the control circuit board 131 from below. In this embodiment, the most important role is played by the protuberance 138 provided near the left-right center near the position where a specific portion of the housing 102 deformed by the impact of the drop first hits the control circuit board 131. The protuberance 138 plays two roles: one is to determine the vertical position of the control circuit board 131, and the other is to allow the specific portion of the deformed housing 102 to hit the protuberance, so that the impact is not transmitted to the control circuit board 131 but is transmitted to the beam portion of the housing 102 (the ribs 122 to 124 shown in FIG. 23) via the board case 135. Below step 138b of raised portion 138, cone-shaped portion 138a is formed, the diameter of which increases toward bottom surface 134, or the diameter of which increases toward an inverted funnel. The reason for using such a cone-shaped portion is to disperse the impact applied to raised portion 138 via screw 146 and transmit it to bottom surface 134, thereby preventing stress from concentrating on a local portion of board case 135. By using cone-shaped portion 138a, it is possible to suppress a reduction in the mounting area of ​​electronic elements mounted on the lower surface side of control circuit board 131.

[0071] A cylindrical portion 138c is formed above the conical portion 138a. The cylindrical portion 138c becomes a screw boss for fixing the screw. The upper surface of the cylindrical portion 138c becomes a small-diameter annular surface 138d. The screw 141 is made of metal, and even if a strong impact is applied from above to below, the impact point is not destroyed, and the impact can be effectively dispersed and transmitted from the protruding portion 138 to the bottom surface 134. The portion where the screw 142 is provided is almost directly below a specific portion of the handle portion 102b of the housing 102 that is most likely to deform. The screw 141 is not essential, and the cylindrical portion 138c may be configured to receive a load by having a columnar shape without providing the screw 141. 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 in a non-contact state with a small distance therebetween. 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 to 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 raised portion 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 vicinity of the front edge of control circuit board 131 is held in a state where the lower surface is placed on step portion 137. Therefore, control circuit board 131 cannot move downward, but can move upward. The vicinity of 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 screw 142. In this way, control circuit board 131 is screwed at only one point, so even if control circuit board 131 is deformed at a point other than the screwed point, it can slide with board case 135, so stress is not concentrated at a specific point of control circuit board 131, and damage to the mounted elements and circuit pattern 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 control circuit board 131. To enable double-sided mounting, a predetermined gap is provided between the lower surface of control circuit board 131 and bottom surface 134 of board case 135. In addition, a predetermined gap is provided between the upper surface of control circuit board 131 and opening surface 136 of board case 135.

[0074] FIG. 25 is a partial enlarged view of the M portion in FIG. 23. As can be seen from this enlarged view, the height of the cylindrical portion 138c extending upward from the step portion 138b is slightly higher than the total height of the control circuit board 131 and the flat plate portion 155 of the switch panel 150. Therefore, the fastening by the screw 141 does not completely restrict the vertical movement of the control circuit board 131 and the switch panel 150. Also, the size of the through hole 132a of the control circuit board 131 is sufficiently larger than the size of the cylindrical portion 138c. The screw 141 is made of metal, and the top of the screw 141 has a gap between it and a specific portion 104 of the housing 102. Therefore, during normal operation, the housing 102 and the screw 141 maintain a non-contact state, but if the housing 102 is dropped in an upright position, the specific portion 104 deforms downward and comes into contact with the top of the screw 141. The screw 141 is connected to the board case 135, but is not firmly fixed to the control circuit board 131 and the switch panel 150. In other words, although raised portion 138 restricts the movement of control circuit board 131 in the front / back, left / 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 greatly 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 greatly 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 curable resin and cured so that all or almost all of the electronic components mounted on control circuit board 131 are covered with the resin. The resin should be 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 the conventional control circuit unit 230. In FIG. 26A, the screws 141 and 142 and the electronic elements mounted on the control circuit board 131 are omitted. Here, the portion (step 137) of the board case 135 that contacts the lower front edge of the control circuit board 131 is shown by a dotted line. In the board case 135, a step 137a (see also FIG. 21) that continues in the left-right direction is formed on the inside of the front edge 135a. In addition, the shape is a rectangle with the corners cut diagonally when viewed from above, and steps 137b and 137c are formed on the inside of the step 137a, so that the lower front portion of the control circuit board 131 is stably held. 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 ribs 137f, 137g (see Figure 21) extending in the vertical direction.

[0077] A raised portion 138 that supports the lower surface of the control circuit board 131 is provided near the center of the control circuit board 131. The raised portion 138 is preferably provided at the left-right center, and this left-right center is located at a position that passes through the dividing surface of the housing 102. The raised portion 138 is provided slightly forward of the center point when viewed in the front-rear direction. This is because when the switches 161 and 162 arranged on the control circuit board 131 are pressed, a downward force is applied to the control circuit board 131, and the raised portion 138 must be provided to resist this force. The plungers of the switches 161 and 162 are each included within a pentagonal (approximately triangular) range surrounded by the steps 137, the imaginary line 36a connecting the rightmost position 137d of the step 137b and the rear contact of the step 138b of the step 138, the imaginary line 36b connecting the leftmost position 137e of the step 137c and the rear contact of the step 138b of the step 138, and the step 137. Such a positional relationship allows the force applied to control circuit board 131 when switch 161 or switch 162 is operated to be effectively transmitted to board case 135, making it possible to favorably support switch panel 150 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 favorable operability of switch panel 150.

[0078] A through hole 132b for passing a screw 142 (see FIG. 21) is formed on the rear side of the control circuit board 131. A screw boss 139 with a screw hole is formed on the board case 135. The screw boss 139 and the through hole 132b are preferably located at a position that coincides with the dividing surface of the housing 102 or at a position close to the dividing surface. The rear side of the raised portion 138 is in a state of being raised above the board case 135 except for the screw boss 139. Therefore, even if a strong downward impact is applied from directly above the screw 141 of the board case 135, the impact is directly transmitted to the board case 135 via the raised portion 138, so that an excessive force that may distort the control circuit board 131 is unlikely to be transmitted. Even if a force that may distort the board case 135 is applied, the force is unlikely to be transmitted to the control circuit board 131, so that the risk of damage to the circuit elements mounted on the control circuit board 131 can be effectively reduced.

[0079] 26(B) is a top view of conventional board case 235 and control circuit board 231. The shape of control circuit board 231, the shape of board case 235, and the arrangement of switches 161 and 162 are not the same, but this is the result of matching them to the shape of the housing. However, the lower surface of control circuit board 231 is held by step portion 236 all around the 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] The switch panel fixing holes 232a and 232b are holes provided in the control circuit board 131 to fix 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 the fixing holes 232a and 232b, respectively, and the underside of the control circuit board 131 is hooked by the fixing hooks. In addition, the control circuit board 131 is biased against the fixing hooks by an elastic body (not shown) on the upper surface of the control circuit board 131, so that the switch panel is stably fixed. As described above, the conventional board case 235 had a problem of high cost due to the use of an elastic body, but the present invention uses only a minimum number of screws and hardening resin to fix the switch panel, which reduces the stress generated in the control circuit board 131 and also reduces the number of parts (cost reduction).

[0081] FIG. 27 is a partial enlarged view of the vicinity of the support part of the control circuit board 131 according to a modification of the seventh embodiment. The shape of the protruding part 188 serving as the support part is different from the shape shown in FIG. 25. The protruding part 188 has the same shape as the cone part 188a and the step part 188b protruding from the bottom surface of the board case 185, but the height (axial length) of the cylindrical part 188c is formed to be lower. The height of the cylindrical part 188c is made higher than the plate thickness of the control circuit board 131, and the positional relationship is set so that the flat plate part 155 of the switch panel 150 and the control circuit board 131 do not come into strong contact with each other. In this modification, the specific part 104 and the upper surface position (opening 186) of the board case 185 are formed to have a small gap. Therefore, the vibration transmitted from the housing 102 to the control circuit board 131 during normal operation is suppressed to a small value.

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

[0083] FIG. 28(B) is a diagram showing the position of stress transmitted from the maximum deformation point of the conventional housing 202 to the board case 135. In the conventional housing 202, the force applied to a specific portion as shown by the arrow 248 is transmitted to the control circuit board 231, and then transmitted to the board case 235 via the step on the lower side of the outer edge of the control circuit board 231. The force applied to the control circuit board 231 is supported in the directions of the arrows 249a and 249b by the step portion 236 of the board case 235. In this way, the deformation caused by a strong impact such as a drop passes through the control circuit board 231 in the process of being transmitted to the housing 202 on the lower side of the board case 235, so that the electronic elements mounted on the control circuit board 231 are easily damaged. On the other hand, if the force is directly transmitted to the housing 202 via the raised portion 138 as shown in FIG. 28(A), the risk of the control circuit board 231 being damaged is reduced. EXAMPLES

[0084] FIG. 29 is a cross-sectional view showing the control circuit unit 130 of the power tool 101 according to the eighth embodiment of the present invention, where (A) is a vertical cross-sectional view passing through the dividing surface 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 switches 161 and 162 are not provided in the board case 135A. When the switches 161 and 162 are not provided, an opening for the switch unit is not provided in the housing 102. In addition, it is not necessary to form a step corresponding to the step portion 137 (see FIG. 24) on the inner side of the front wall of the board case 135A as shown in FIG. 24. 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 approximately 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, the inner space of board case 135A is substantially filled with hardening resin, so that control circuit board 131 does not move excessively.

[0086] The present invention has been described above based on the first to eighth embodiments, but the present invention is not limited to the above-mentioned embodiments and can be modified in various ways without departing from the spirit of the present invention. For example, in the above-mentioned embodiments, an impact tool is used as an example of the power tool 1, but the present invention is not limited to the impact tool, and can be applied to other battery-driven tools in which a battery attachment part is formed at the tip of the handle part and a battery and a circuit board are provided. Furthermore, the present invention is not limited to the cordless type power tool driven by a battery, and can be applied to a corded type power tool that is driven by connecting the power cord to an external power source such as a commercial power source. When applied to a corded type power tool, the battery attachment part 2c is made into a storage part with a closed shape at the bottom, the storage part is made into a split type like the body part and the handle part of the housing, an opening surface is provided so as to intersect with the split surface, a switch panel is attached to the opening surface, and the control circuit part 30, 60 to 90 is stored inside the storage part. [Explanation of symbols]

[0087] 1 Power tool 2, 2A, 2B Housing 2a Body part 2b Handle section 2c Battery mounting section 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 portion 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 Recess 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 section 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 Electric tool 102 Housing 102b Handle part 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 Front edge (of board case) 135c, 135d (board case) inner wall portion 136 opening surface 137, 137a~137c Stepped portion 137d Rightmost position (of the stepped portion) 137e (step) leftmost position 137f, 137g Rib 138 raised portion 138a cone portion 138b step portion 138c cylindrical portion 138d toric surface 139 thread boss 141, 142 Screw 146 Screw 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 cone 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 Rib 238c Recess 239a, 239b Rib 300 Battery 301 Latch button A1 (motor and output shaft) axis B1 (Handle) central axis C1 (Battery mounting part) left and right center line (split surface)

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 section including a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and a resin filled inside the board case so as to immerse upper and lower surfaces of the control circuit board; a housing section provided below the handle section, the housing section having a protruding portion protruding forward and in left and right directions from the handle section, the housing section housing the control circuit section; an input / output operation unit provided on an upper surface of the protruding portion so as to extend in the left-right direction and through which an operator can perform an input operation; an opening extending in the left-right direction on an upper surface of the protruding portion and divided by the dividing surface, the opening having an outer edge for holding 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, the portion being located above the control circuit unit and facing 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 and below the control circuit portion in the up-down direction and at a position coinciding with the 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 that is supported by the housing in the accommodating portion and that has 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 integrally formed 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 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 section including a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and a resin filled inside the board case so as to immerse upper and lower surfaces of the control circuit board; a housing section provided below the handle section, the housing section having a protruding portion protruding forward and in left and right directions from the handle section, the housing section housing the control circuit section; an input / output operation unit provided on an upper surface of the protruding portion so as to extend in the left-right direction and through which an operator can perform an input operation; an opening extending in the left-right direction on an upper surface of the protruding portion and divided by the dividing surface, the opening having an outer edge for holding 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, the portion being located above the control circuit unit and facing the control circuit unit; a first support portion that supports the control circuit portion from below, the first support portion being located below the control circuit portion in the up-down direction within the housing portion; a second support portion extending upward from a 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 that is supported by the housing in the accommodating portion and that has 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 integrally formed 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 section including a control circuit board for controlling the motor, a board case for accommodating the control circuit board, and a resin filled inside the board case so as to immerse upper and lower surfaces of the control circuit board; a housing section provided below the handle section, the housing section having a protruding portion protruding forward and in left and right directions from the handle section, the housing section housing the control circuit section; an input / output operation unit provided on an upper surface of the protruding portion so as to extend in the left-right direction and through which an operator can perform an input operation; an opening extending in the left-right direction on an upper surface of the protruding portion and divided by the dividing surface, the opening having an outer edge for holding 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, the portion being located above the control circuit unit and facing 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 penetrating a through hole formed in the control circuit board, and the control circuit board configured to extend from the front to the rear of the second support portion; A power tool characterized by:

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