A power tool comprising a housing and a brushless direct-current (BLDC) motor disposed within the housing. The motor includes a stator and a rotor rotatable relative to the stator. The power tool is configured to generate a power output from the motor such that a quotient obtained by the power output measured in Watts (Wout), divided by an input measured in Volt-Amperes (Vain), and further divided by a diameter of the motor measured in meters (m), is greater than 10 Wout/Vain/m.

An electric working machine according to one aspect of the present disclosure includes an output shaft, a motor, a transmitting device, a drive device, a controller, and a current path. The transmitting device has transmittable allowable torque and transmits rotation of the motor to the output shaft. The drive device energizes the motor with electric supply from a battery in accordance with a command from outside the electric working machine. The current path is configured to be able to energize the motor with a current value larger than an allowable current value required to limit torque generated in the transmitting device due to rotation of the motor to the allowable toque or smaller.

Batteries having different form factors and power tools that are capable of using such batteries are described. In some embodiments, a power tool may use batteries having a post form factor as well as batteries having a slide form factor.

A brushless direct-current motor is provided includes an inner stator and an outer rotor. A rotor shaft extends through a stator core of the inner stator. A first end cap includes a radial back plate disposed on a first side of the stator and a front center opening through which the rotor shaft is supported via a front bearing. A second end cap includes an inner annular body extending axially inwardly and forming a rear center opening, an outer annular body, and a main body extending on a second side of the stator. The inner annular body includes a first portion that extends at least partially into an opening of the stator core and supports the rotor shaft via a rear bearing, and a second portion rearward of the first portion that received a rear end of the rotor shaft therein and houses a sensor board therein.

A brushless motor includes a stator assembly including a generally-cylindrical stator body having a center bore, teeth extending from the stator body towards the center bore and defining slots in between, and windings wound around the teeth; and a rotor assembly rotatably received within the center bore and includes a rotor shaft and a generally-cylindrical rotor body. The motor further includes at least one rotor bearing mounted on the rotor shaft, and at least one bearing support member supporting the rotor bearing. The bearing support member includes a radial body forming a bearing pocket for receiving the rotor bearing therein, and axial post inserts received within the slots of the stator assembly between adjacent sets of windings and engaging an inner surface of the stator body to support the rotor bearing with respect to the stator assembly along a center axis of the center bore of the stator assembly.

A remote controlled vibration imparting device for a concrete finishing tool uses a housing having a chamber surrounded by an inner surface of the housing. A vibrator with a support, a rotor with a shaft and weighted body, a motor, and a resilient link between the shaft and the motor is positioned within the housing chamber. The vibrator also includes a resilient band to separate the vibrator from the housing inner surface. First and second adaptors are employed for the housing to be placed between the handle and the terminus of a concrete finishing tool.

A power tool with a combined printed circuit board (PCB) having a doughnut shape and located coaxially with a motor shaft. The combined PCB is secured to a heat sink on one end of the motor and a metal end piece is positioned on an opposite end of the motor. The metal end cap and heat sink are secured to one another via fasteners to provide a rigid coupling. A tabbed end piece is provided between the heat sink and the motor stator and is also secured into place via the fasteners. The tabbed end piece includes wire support tabs that provide strain relief to motor coil leads. The wire support tabs extend axially from circumferential locations of the tabbed end piece and include channels to guide the motor coil leads to solder contact points on the combined PCB.

A motor drive system is provided, which includes: an inverter including an upper-half bridge and a lower-half bridge, the upper-half bridge and the lower-half bridge each including at least two semi-conductive switch elements, where the inverter is configured to convert a voltage provided by a power supply to an alternating current to drive a motor; a microcontroller configured to output a drive signal to the alternately turn on each two of the at least two semi-conductive switch elements of the upper-half bridge and each two of the at least two semi-conductive switch elements of the lower-half bridge when the motor performs braking, whereby a motor winding and the turned-on semi-conductive switch elements form a circuit a capacitor configured to supply power to the microcontroller when the motor performs braking.

A brushless direct current motor for a power tool. The motor includes a stator assembly including a stator core having stator laminations with an annular portion and inwardly extending stator teeth. The motor also includes a rotor assembly including a rotor core having rotor laminations and defining a central aperture that receives an output shaft. The rotor assembly also includes a rotor end cap on a first side of the rotor core having a bearing holder and defining a channel, wherein the channel is open on a side of the rotor end cap facing the rotor core. The motor further includes a bearing provided in the bearing holder that couples the rotor end cap to the output shaft and a position sensor board assembly provided in the channel of the rotor end cap and configured to provide position information of the rotor core to a motor controller.

A power tool is configured to receive power from a power supply. The power tool may include a rectifier that may output a rectified signal to a DC power bus. A switching arrangement may operate to deliver electric power from the DC power bus to an electric motor. A switch path may be electrically coupled in parallel with the rectifier on the DC power bus. The switch path includes an auxiliary capacitor in series with a switch and a state of the switch controls a discharging path for the auxiliary capacitor. A switch control circuit may be configured to detect voltage associated with at least one of the AC power supply or the DC power bus and to control state of the switch in accordance with magnitude of the detected voltage.