A ring element includes a convex, in particular rounded, surface element for arrangement on at least one axial end region of a winding section of an electric motor rotor. The surface element provides a minimum radius curvature for supporting an inner layer of a rotor winding on the winding head. An insulating lamination element for an electric motor rotor onto which a rotor winding is intended to be wound includes the ring element. An electric motor, in particular a universal motor, includes a rotor with a rotor winding having the ring element. An electric machine tool, in particular a handheld electric machine tool such as an angle grinder, a drill, a saw or the like, includes the electric motor.

A pole-number-changing rotary electric machine includes: a rotary electric machine; an n-group inverter; and a control unit for controlling the n-group inverter, wherein the control unit controls current phases of a current flowing through stator coils such that a current phase degree of freedom, which is a number of current phases per pole pair controllable by the n-group inverter, is equal to a number of groups n×a number of phases m/2 at a time of high polarity driving and the number of groups n×the number of phases m at a time of low polarity driving, where the number of groups n is a multiple of 4 and the number of phases m is a natural number of 3 or more and relatively prime to the number of groups n.

A rotor for a rotary electric machine, the rotor having an axis of rotation and including a rotor shaft extending parallel to the axis of rotation, a rotor body mounted on the rotor shaft and having a plurality of teeth protruding radially, and at least one field coil wound around the plurality of teeth, the field coil forming coil ends at axial ends of the teeth. At least one cover mounted on the rotor shaft and configured to cover the coil ends. The cover includes a plurality of holes configured to each receive a solid balancing element which provides an additional mass to the rotor in order to balance said rotor.

A method and apparatus for a rotor assembly. The rotor assembly includes a rotor core having a rotatable shaft and defining at least one rotor post, a winding wound around the post that defines an end turn, and at least one coolant conduit defined in part by an end support and in a thermally conductive relationship with a portion of the winding.

In a method for producing an individual-segment rotor for an electric machine, a shaft is arranged in a mold and a plurality of laminated core segments, which are at a distance from one another, are arranged on the circumference of the shaft in a distributed manner in the mold. The laminated core segments each have a fixing contour for a form closure for radially fixing the laminated core segment on the shaft. In addition, a permanent magnet is arranged between each pair of laminated core segments. An intermediate space between the shaft and each fixing contour of the laminated core segments is filled with a curable nonmagnetic material. The curable nonmagnetic material forms a form closure with respect to the radial direction with each fixing contour, and therefore each laminated core segment is retained on the shaft by the form closure.

A coil bobbin for a brushless alternator includes an integrally formed one piece bobbin body that has a first end, a second end and a central passage that extends from the first end to the second end. A coil support portion of the body is positioned at the first end and has a first cylinder of a first diameter bordered by flanges which extend past the first cylinder. A base portion of the body is positioned at the second end. A bobbin extension portion is positioned between the coil support portion and the base portion. The bobbin extension portion includes a second cylinder of a second diameter which is smaller than the first diameter.

A coil bobbin for a brushless alternator includes an integrally formed one piece bobbin body that has a first end, a second end and a central passage that extends from the first end to the second end. A coil support portion of the body is positioned at the first end and has a first cylinder of a first diameter bordered by flanges which extend past the first cylinder. A base portion of the body is positioned at the second end. A bobbin extension portion is positioned between the coil support portion and the base portion. The bobbin extension portion includes a second cylinder of a second diameter which is smaller than the first diameter.

A rotor for an electric machine is disclosed. The rotor has a rotor shaft, a laminated core arranged on the rotor shaft and a plurality of stacked electrical laminations. The rotor also includes a first end plate arranged on an axial side of the laminated core and having radial protrusions arranged along its circumference, a second end plate arranged on the opposite axial side of the laminated core and having radial protrusions arranged along its circumference, a plurality of rotor windings which are each wound around a protrusion of the first end plate and around an axially opposite protrusion of the second end plate. A central cooling duct runs in the rotor shaft for supplying a coolant, and a radial cooling duct runs outwards from the central cooling duct in the laminated core. In addition, an electric machine and a vehicle having an electric machine of this type are described.

A motor may include a shaft, a rotor coupled to the shaft, a stator disposed outside the rotor, and a bus bar disposed on the stator. The bus bar may include a terminal connected to a coil of the stator, the terminal includes a first terminal and a second terminal separated from each other in a circuit manner, the first terminal includes a first neutral terminal and a plurality of first phase terminals, the second terminal includes a second neutral terminal and a plurality of second phase terminals, first curvature centers of the plurality of first phase terminals are disposed to be different, second curvature centers of the plurality of second phase terminals are disposed to be different, and a position of a curvature center of the first neutral terminal is the same as a position of a curvature center of the second neutral terminal.

A motor may include a shaft, a rotor coupled to the shaft, a stator disposed outside the rotor, and a bus bar disposed on the stator. The bus bar may include a terminal connected to a coil of the stator, the terminal includes a first terminal and a second terminal separated from each other in a circuit manner, the first terminal includes a first neutral terminal and a plurality of first phase terminals, the second terminal includes a second neutral terminal and a plurality of second phase terminals, first curvature centers of the plurality of first phase terminals are disposed to be different, second curvature centers of the plurality of second phase terminals are disposed to be different, and a position of a curvature center of the first neutral terminal is the same as a position of a curvature center of the second neutral terminal.