A power tool is provided including a housing including a grip portion; and a brushless direct-current (BLDC) motor at least partially disposed within the grip portion of the housing. The motor includes a stator having a rotor core, a rotor, and front and rear bearing support structures. The stator core includes a non-segmented construction with a maximum diameter of approximately smaller than or equal to 34 mm, and a ratio of a motor size (Km) constant of the motor to a length of the motor is in the range of approximately 0.39 to 0.59 (Nmm/√W)/mm. When powered by a 20V battery pack, a ratio of a maximum power output of the motor to a volume of the motor is at least approximately 0.0106 W/mm{circumflex over ( )}3.

A workpiece spindle for a magnetic-shoe external cylindrical grinding machine a spindle for rotating a ring-shaped workpiece, a holding device for holding the ring-shaped workpiece and a hydraulic magnetic core lifting device coupled to the spindle and to the holding device to vary an axial spacing between the holding device and the spindle. The holding device has a magnetic shoe for clamping the ring-shaped workpiece in the holding device.

A motor assembly includes a stator having a stator core, stator windings, and a routing insulator configured to electrically insulate the stator core from the stator windings; a rotor rotatably received within the stator; and a bearing bridge received at least partially within the routing insulator and including a main body forming a center pocket arranged to support a bearing of the rotor shaft. A circuit board is provided including a circuit board, and an overmold structure forming an annular body on a surface of the circuit board arranged to mate with the main body of the bearing bridge to substantially seal the center pocket from ingress of debris particles.

A device (21) for controlling a spindle of a grinding machine (1) is disclosed. The spindle includes a rotor (5) supported by two radial magnetic bearings, one axial bearing, and a grinding wheel (6). The device includes a storage means (22) for storing control coefficients of the magnetic bearings. The device includes a means for determining a type of the grinding wheel and a type of the rolling bearing ring. A selection means (23) selects control coefficients associated with the determined types of grinding wheel and of rolling bearing ring from among the control coefficients stored in the storage means. The device also includes a means (23) for controlling the radial and axial magnetic bearings. Said means controlling the radial and axial (12) magnetic bearings on the basis of the control coefficients of the determined types of grinding wheel and of rolling bearing ring.

A motor assembly includes a stator having a stator core, stator windings, and an end insulator configured to electrically insulate the stator core from the stator windings; a rotor rotatably received within the stator; a bearing bridge received at least partially within an inner portion of the end insulator and including a main body forming a center pocket arranged to support a bearing of the rotor shaft; and stator terminals supported by the end insulator and extending away from the stator. A circuit board assembly is provided including: an annular body mounted in contact with the main body of the bearing bridge and located radially inward of the stator terminals, and a circuit board mounted on the annular body and being electrically connected to the stator terminals.

A power tool, wherein a lubricant for gearbox lubrication can be accommodated in a gearbox housing interior of the gearbox housing, wherein the output shaft has a first end on which an insert tool unit can be mounted, and has a second end, wherein the output shaft is designed as a hollow spindle with a cavity. A hollow cylinder section is formed at its second end. An actuator is arranged in a rotationally resistant manner to the gearbox housing, which engages with the hollow cylinder section. Between the hollow cylinder section and the actuator, a gap extends along the axis of rotation which at its first end is connected to the cavity and at its second end to the gearbox housing interior. A shaft seal is disposed in the gap, which counteracts the leakage of lubricant from the gap towards the first end of the output shaft.

The invention refers to power tool (10) comprising a tool housing (12), a motor (24) located therein and a tool shaft (36) with a rotational axis (40) and actuated by the motor (24) when in operation. A distal end of the tool shaft (36) is accessible from outside the tool housing (12). The power tool (10) further comprises a polishing pad (38) releasably attachable to the distal end of the tool shaft (36) from outside the tool housing (12) in an axial direction parallel to the rotational axis (40) and, after attachment to the tool shaft (36), held in respect to the tool shaft (36) in the axial direction by means of an axial holding arrangement (80). The axial holding arrangement (80) comprises a first element (36; 38) constituted by the polishing pad (38) or the tool shaft (36) and a second element (38; 36) constituted by the other one of the tool shaft (36) or the polishing pad (38), and at least one locking element (70) held in the first element (36; 38) movably in a radial direction between a retracted position and a locking position, at least one radially extending recess (76) provided in the second element (38; 36) and configured to receive part of the at least one locking element (70) when in its locking position. The locking elements (70) and the second element (38; 36) in and/or around the at least one radial recess (76) are made of a magnetic or ferromagnetic material so that the locking elements (70) are automatically held in their locking positions and in the at least one radial recess (76) by magnetic force.

The invention refers to hand-held power tool (10) comprising a tool housing (12), a motor (24) and a tool shaft (36) having a rotational axis (40) and actuated by the motor (24), and further comprising a working element (38) releasably attachable to the tool shaft (36) from outside the tool housing (12) in an axial direction and, after attachment to the tool shaft (36), held in respect to the tool shaft (36) by means of an axial holding arrangement (80). The axial holding arrangement (80) comprises a first element (36; 38) constituted by one of the working element (38) and the tool shaft (36) and a second element (38; 36) constituted by the other one of the working element (38) and the tool shaft (36), and at least two locking elements (70) assigned to the first element (36; 38) movably in a radial direction between a retracted position and a locking position, at least one recess (66) assigned to the second element (38; 36) for receiving the locking elements (70) when in their locking positions. The locking elements (70) or the second element (38; 36) in and/or around the at least one radial recess (66) comprises a magnetic material and the at least other one of the locking elements (70) and the second element (38; 36) in and/or around the at least one radial recess (66) comprises a magnetic material or a ferromagnetic material. The locking elements (70) are automatically moved into and held in their locking positions and in the at least one radial recess (66) by means of magnetic force after attachment of the working element (38) to the tool shaft (36).

A power tool is provided including a housing having a grip portion with a grip circumference of smaller than or equal to approximately 120 mm; and a brushless direct-current (BLDC) motor at least partially disposed within the grip portion of the housing and configured to output a maximum power output of at least 450 watts. The motor includes a stator including a stator core and stator windings; and a rotor rotatably received within the stator and including a rotor shaft extending along a longitudinal axis and a series of permanent magnet rings mounted sequentially along the longitudinal axis and surrounding the rotor shaft, each permanent magnet including a plurality of magnetic poles.

The invention refers to hand-held power tool (10) comprising a tool housing (12), a motor (24) and a tool shaft (36) having a rotational axis (40) and actuated by the motor (24), and further comprising a working element (38) releasably attachable to the tool shaft (36) from outside the tool housing (12) in an axial direction and, after attachment to the tool shaft (36), held in respect to the tool shaft (36) by means of an axial holding arrangement (80). The axial holding arrangement (80) comprises a first element (36; 38) constituted by one of the working element (38) and the tool shaft (36) and a second element (38; 36) constituted by the other one of the working element (38) and the tool shaft (36), and at least two locking elements (70) assigned to the first element (36; 38) movably in a radial direction between a retracted position and a locking position, at least one recess (66) assigned to the second element (38; 36) for receiving the locking elements (70) when in their locking positions. The locking elements (70) or the second element (38; 36) in and/or around the at least one radial recess (66) comprises a magnetic material and the at least other one of the locking elements (70) and the second element (38; 36) in and/or around the at least one radial recess (66) comprises a magnetic material or a ferromagnetic material. The locking elements (70) are automatically moved into and held in their locking positions and in the at least one radial recess (66) by means of magnetic force after attachment of the working element (38) to the tool shaft (36).