Abstract: A motor for electric power tools according to an embodiment includes: a rotor having a rotational shaft; a stator having a coil to rotate the rotor; a first substrate mounting a sensor element to detect a rotational position of the rotor; and a second substrate mounting a switching element to change, based on a result of detection by the sensor element, a conducting direction in which a current flows with respect to the coil. The first substrate and the second substrate are arranged side by side along, and intersect at right angles with, the rotational shaft.

Abstract: An electric power tool includes a bearing retainer that retains a bearing for supporting a motor shaft, a transmission mechanism that transmits a rotational output of a motor to a front-end tool and a rotating body attached to an end of the motor shaft. The bearing retainer includes an extension that extends in a direction of axial line from an end face position on the bearing. At least a part of the rotating body is provided in front of a rear end of the extension.

Abstract: A secondary hammer support structure in a rotary impact tool is structured such that a plurality of steel balls are disposed between a secondary hammer and a retaining member. The plurality of steel balls are arranged between the first retaining groove of the secondary hammer and the second retaining groove of the retaining member. The retaining member is formed as a member separate from the spindle and has a retaining surface for retaining steel balls and a mounting surface mounted to the spindle so as not be rotatable. The mounting surface of the retaining member is mounted to a front member of a carrier.

Abstract: A motor for electric power tools according to an embodiment includes: a rotor having a rotational shaft; a stator having a coil to rotate the rotor; a first substrate mounting a sensor element to detect a rotational position of the rotor; and a second substrate mounting a switching element to change, based on a result of detection by the sensor element, a conducting direction in which a current flows with respect to the coil. The first substrate and the second substrate are arranged side by side along, and intersect at right angles with, the rotational shaft.

Abstract: An electric power tool includes a bearing retainer that retains a bearing for supporting a motor shaft, a transmission mechanism that transmits a rotational output of a motor to a front-end tool and a rotating body attached to an end of the motor shaft. The bearing retainer includes an extension that extends in a direction of axial line from an end face position on the bearing. At least a part of the rotating body is provided in front of a rear end of the extension.

Abstract: A secondary hammer support structure in a rotary impact tool is structured such that a plurality of steel balls are disposed between a secondary hammer and a retaining member. The plurality of steel balls are arranged between the first retaining groove of the secondary hammer and the second retaining groove of the retaining member. The retaining member is formed as a member separate from the spindle and has a retaining surface for retaining steel balls and a mounting surface mounted to the spindle so as not be rotatable. The mounting surface of the retaining member is mounted to a front member of a carrier.

Abstract: An impact wrench includes a driving unit, a spindle configured to be rotated by the driving unit, an anvil arranged in front of the spindle in a direction of a rotational axis of the spindle, a primary hammer that is capable of rotating about the rotational axis of the spindle and moving in the direction of the rotational axis of the spindle, a secondary hammer having a cylindrical part in which the primary hammer is housed and that rotates synchronously with the primary hammer, the cylindrical part being configured to receive the spindle, and a rotary impact mechanism that impulsively engages the primary hammer with the anvil to rotate the anvil about the rotational axis of the spindle.

Abstract: To improve the durability of a bearing mechanism such as a rolling bearing that is provided between a secondary hammer and a spindle in an impact wrench configured to firmly tighten screws by applying an impact in the rotational direction of an anvil, using a primary hammer and the secondary hammer, a technique is provided in which a rolling bearing is used as the bearing mechanism, the inner circumference of the secondary hammer is press-fitted to an outer ring of the rolling bearing, and a gap is created between the outer circumference of a spindle and an inner ring of the rolling bearing. The created gap can exhibit the effect of cushioning precession rotation of the secondary hammer to reduce the radial load that is applied to the rolling bearing, and, as a result, improve the durability of the rolling bearing and extend the life of the bearing.