A cutting insert is provided, comprising a top surface, a bottom surface, a plurality of side surfaces spanning therebetween, and a cutting edge formed at an intersection of the side surface and a forwardly-disposed portion of the top the surface. It further comprises a cooling cavity projecting into the insert, a top end thereof being disposed further forwardly than an open bottom end thereof. The cooling cavity defines at least one molding axis such that a solid element having the shape of the cooling cavity and completely inserted therein may be retracted intact therefrom along a linear path parallel to the molding axis. A circumscribing portion is formed on the side surfaces encircling the cutting insert. The circumscribing portion is formed parallel to the molding axis and has a non-zero height along its entire extent. The cutting insert does not extend beyond the circumscribing portion.

A rectifier circuit for rectifying an AC voltage supplied from a commercial power supply into a DC voltage, a smoothing capacitor for smoothing the output of the rectifier circuit, and an electrically powered tool for supplying the smoothed pulsating DC voltage to a motor by an inverter circuit, wherein when the motor is driven while no load is being applied to a tip tool, the smoothed DC voltage repeatedly generates a maximal value and a minimum value so as to synchronize with the fluctuation in the AC voltage. During no-load rotation, control is performed so that driving is performed at a value that is less than a threshold value D.sub.1 for the duty ratio at which the generation of a gear sound starts in any of the speed dial setting values 1-6. It is thereby possible to suppress a gear sound generated by a power transmission mechanism during no-load rotation.

A hand-held power tool includes an electric motor, a housing, and a housing cover. The housing includes an opening located in the vicinity of carbon brushes of the electric motor, such that the carbon brushes can be removed through the opening in the housing. The housing cover includes air inlets through which cooling air can flow into the interior of the housing. The opening in the housing is detachably closed by the housing cover.

An electric hammer can collect dust without using an external dust collection device. An electric hammer includes a motor, a body incorporating the motor, a striker assembly operable in response to the motor being driven to strike a bit attached along a striking axis, a dust collection fan rotatable in response to the motor being driven, a dust collection channel having a suction port being open toward a tip of the bit to generate a suction force in the suction port in response to rotation of the dust collection fan, and a dust collector located on the dust collection channel to collect dust sucked through the suction port.

A hand-held power tool, in particular a hammer drill or combi-hammer, including a tool housing having an accommodating region designed for accommodating a rechargeable tool battery, wherein, in the accommodating region, a contact region for electrically contacting the rechargeable tool battery as well as a connection region that is electrically connected to the contact region is provided, wherein the connection region is designed to convey a supply current provided by the rechargeable tool battery to an electric drive motor of the hand-held power tool, wherein the hand-held power tool has a cooling fan arranged in the tool housing and operated by the electric drive motor, by which cooling air for cooling the accommodating region can be sucked through the accommodating region, wherein at least one partitioning element is provided in the accommodating region in such a way that the contact region remains substantially free from cooling air sucked through the accommodating region.

An electric powered work machine in one aspect of the present disclosure includes a motor, a current-carrying path, a switching circuit, a circuit board, a metal case, and a heat radiation sheet. The circuit board includes a first surface, a second surface, a first hole group, a board conductive line, and a circuit arrangement area.

A handheld machine tool has a drive motor for driving a tool holder, in which a tool is able to be accommodated. In addition, a cam-action mechanism for generating a hammer function is provided, which includes a cam-action mechanism holder and a notched disk. The cam-action mechanism holder is in contact with a heat-dissipating component situated inside the housing.

A power tool efficiently cools a motor and a brush, with a distance for insulation left between an inlet and an urging member. A power tool includes a motor, an output unit, a fan, a housing accommodating the motor and the output unit, having an inlet to suck in air from outside in response to rotation of the fan and an outlet to discharge the air sucked in, and accommodating the motor along a flow of the air between the inlet and the outlet, a brush retainer downstream from the inlet and including a brush and a conductive urging member urging the brush against a commutator, and a nonconductive cover located between the urging member and the inlet and covering the urging member.

A work machine includes: a motor; an output shaft, rotated by driving of the motor; a first fan, fixed to and rotating integrally with the output shaft; a second fan, located on one side of the first fan in an axial direction of the output shaft, fixed to and rotating integrally with the output shaft; and a rectification member, accommodating the first and second fans, and, when the output shaft rotates to one side in a rotation direction, causing a first airflow blown out from the first fan and a second airflow blown out from the second fan to join together and flow out toward one side in the axial direction. The rectification member includes a rectification section in which the second airflow is rectified to flow to the one side in the axial direction and is prevented from flowing to the other side in the axial direction.

A power tool having a hammer mechanism, including: a connecting part connectable with a dust collector, and with a connection flow path to suck in the air from the dust collector to generate a suction power in the dust collector; a motor with a rotating shaft; a first fan to rotate with the rotating shaft and generate a first air flow to cool down the motor; a second fan to rotate with the first fan and generate a second air flow to generate the suction power; a housing with a first exhaust port to discharge the first air flow and a second exhaust port to discharge the second air flow; a first exhaust flow path to guide the first air flow to the first exhaust port; and a second exhaust flow path separated from the first exhaust flow path to guide the second air flow to the second exhaust port.