An electric motor apparatus is described that utilizes a Halbach array and a ferrofluid core. The electric motor comprises a rotor assembly and a stator assembly, each of which utilizes a Halbach array. A ferrofluid core is utilized in the stator, which results in a motor that is less susceptible to core loss and operates with increased efficiency.

A PMDC motor includes a housing, a stator magnet fixed to the inner circumferential surface of the housing, a rotor core received in the housing and facing the stator magnet, and rotor windings wound around the rotor core. The rotor core includes a plurality of rotor teeth, each of the rotor teeth including a tooth body and a tooth tip. A ratio of the outer diameter of the rotor core to an outer diameter of the housing is in the range of 0.6 to 0.67. Compared to the existing PMDC motor, the PMDC motor of the present invention can satisfy the same performance requirement, while reducing the size and weight of the rotor core and hence the weight of the rotor windings. In this way, the total weight and hence the moment of inertia of the rotor is reduced, thereby effectively reducing the noise generated during operation of the motor.

A PMDC motor includes a housing, a stator magnet fixed to the inner circumferential surface of the housing, a rotor core received in the housing and facing the stator magnet, and rotor windings wound around the rotor core. The rotor core includes a plurality of rotor teeth, each of the rotor teeth including a tooth body and a tooth tip. A ratio of the outer diameter of the rotor core to an outer diameter of the housing is in the range of 0.6 to 0.67. Compared to the existing PMDC motor, the PMDC motor of the present invention can satisfy the same performance requirement, while reducing the size and weight of the rotor core and hence the weight of the rotor windings. In this way, the total weight and hence the moment of inertia of the rotor is reduced, thereby effectively reducing the noise generated during operation of the motor.

A hand held power tool that includes a housing, a power source input configured to receive power from a power source, and a brushed motor located within the housing. The brushed motor is configured to receive power from the power source input. The brushed motor includes a first primary stator pole including a first pole neck and a first pole arc, a second primary stator pole including a second pole neck and a second pole arc, a first stator interpole including a first interpole neck, and a second stator interpole including a second interpole neck. The first stator interpole and the second stator interpole are each positioned between the first primary stator pole and the second primary stator pole.

A drive unit for an adjustment system for a motor vehicle has an adjustable element moved by an electric motor. The dive motor is operated electromagnetically. A magnetic field sensor is arranged on a pole pot or a housing of the drive motor to provide an electrical sensor signal dependent on a magnetic field. A control unit is configured to detect the magnetic field. The magnetic field varies on rotation of a rotor of the drive motor, so that a relative position change of the adjustable element can be derived from the electrical sensor signal.

A PMDC motor includes a housing, a stator magnet fixed to the inner circumferential surface of the housing, a rotor core received in the housing and facing the stator magnet, and rotor windings wound around the rotor core. The rotor core includes a plurality of rotor teeth, each of the rotor teeth including a tooth body and a tooth tip. A ratio of the outer diameter of the rotor core to an outer diameter of the housing is in the range of 0.6 to 0.67. Compared to the existing PMDC motor, the PMDC motor of the present invention can satisfy the same performance requirement, while reducing the size and weight of the rotor core and hence the weight of the rotor windings. In this way, the total weight and hence the moment of inertia of the rotor is reduced, thereby effectively reducing the noise generated during operation of the motor.

A PMDC motor includes a housing, a stator magnet fixed to the inner circumferential surface of the housing, a rotor core received in the housing and facing the stator magnet, and rotor windings wound around the rotor core. The rotor core includes a plurality of rotor teeth, each of the rotor teeth including a tooth body and a tooth tip. A ratio of the outer diameter of the rotor core to an outer diameter of the housing is in the range of 0.6 to 0.67. Compared to the existing PMDC motor, the PMDC motor of the present invention can satisfy the same performance requirement, while reducing the size and weight of the rotor core and hence the weight of the rotor windings. In this way, the total weight and hence the moment of inertia of the rotor is reduced, thereby effectively reducing the noise generated during operation of the motor.

A hand held power tool that includes a housing, a power source input configured to receive power from a power source, and a brushed motor located within the housing. The brushed motor is configured to receive power from the power source input. The brushed motor includes a first primary stator pole including a first pole neck and a first pole arc, a second primary stator pole including a second pole neck and a second pole arc, a first stator interpole including a first interpole neck, and a second stator interpole including a second interpole neck. The first stator interpole and the second stator interpole are each positioned between the first primary stator pole and the second primary stator pole.

The invention concerns a drive unit for an adjustment system (1), in particular in a motor vehicle, with an adjustable element (2) moved by an electric motor, comprising: a drive motor (4) operated by an electromagnet, a magnetic field sensor (9) which is arranged on a pole pot (42) or a housing of the drive motor (4) in order to provide an electrical sensor signal dependent on the magnetic field, a control unit (7) which is configured to detect a magnetic field which varies on rotation of a rotor (44) of the drive motor (4), so that in particular a relative position change of the adjustable element (2) can be derived from the electrical sensor signal.

Provided are a rotor, a manufacturing method of the rotor, and a DC motor including the rotor, the rotor including: a core around which a winding is wound, the core being rotatable integrally with a shaft; a commutator being fixed to the shaft and having a terminal to be connected to one end of the winding; and a conduction plate being externally fitted onto the shaft via an insulator part between the terminal of the commutator and the core, the conduction plate having a connection part to be connected to the other end of the winding, wherein an axial direction position of the connection part is set in an intermediate portion that is between a winding projection of the winding and the terminal.