A high torque dual speed turbine rotor for a lightweight hand held tool for grinding and polishing or for use with a spindle mounted pneumatic machine. The high torque dual speed turbine rotor includes a two-piece shaft with flow control screw disposed within the shaft. The shaft includes a first set of hollow openings, at a first position from one end of the shaft, in fluid communications with a first annular chamber of a rotor. There is also a second set of hollow opening, at a second position from the one end of the shaft, in fluid communications with a second annular chamber of the rotor. The flow control screw moves inside a threaded axial bore of the shaft from an open position inside the axial bore to the closed position corresponding to the second set of hollow openings.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

Lathe control systems and methods are described including stopping a motor prior to reversing direction as well as methods and systems that implement voltage and/or current protection thresholds.

An example method includes performing a machining operation by providing linear movement of a tool along a feed axis relative to a workpiece while superimposing oscillation of the tool onto the feed axis and providing rotation of the tool relative to the workpiece. During an optimization mode, the machining operation is performed on a first workpiece portion while providing the linear movement at an initial feed velocity, and sequentially superimposing the oscillating at a plurality of different frequencies. An optimal oscillation frequency is determined from the plurality of different frequencies which causes the tool to apply less force to the first workpiece portion at the initial feed velocity than others of the frequencies. During a run mode, the machining operation is performed on a second workpiece portion having a same composition as the first workpiece portion while superimposing the oscillation at the optimal oscillation frequency.

The feed axis device of a machine tool is equipped with first and second planetary gear speed reducers, each of which is obtained from an inner element, outer element, and intermediate elements that are disposed between the two, the elements being disposed so as to be mutually rotatable and combined in series so that one of the three elements is a fixed section, one of the two remaining elements is the input section and the other is the output section. The element that is the input section of the first speed reducer and the element that is the input section of the second speed reducer are connected to a single drive source. The element that is the output section of the first speed reducer and the element that is the output section of the second speed reducer are connected. The feed axis device is provided with an actuator.

A variable-speed direct current motor comprising a stator (22), a rotor (23) arranged within the stator, and a motor drive device (40) arranged partly at the stator and partly at the rotor, wherein the stator comprises a yoke (25) defining a cylindrical cavity (31), and a plurality of permanent magnets (24) arranged at the yoke, wherein the rotor comprises a cylindrical core (26) and a conductor structure (47) arranged at the core, wherein the motor drive device comprises an alternating current transformer (41) having a primary winding (42) arranged at the stator and a secondary winding (43) arranged at the rotor, a rectifier device (44) arranged at the rotor and connected with the secondary winding, a direct current supply device (45) arranged at the rotor (23) and connected with the rectifier device (44), and with the conductor structure (47), and an operation control device (48) comprising a first unit (49) arranged at the rotor (23) and a second unit (50) arranged externally of the rotor and wirelessly communicating with the first unit.