Abstract: A motor has a field body having a number of field poles and an armature body having a number of coils which is placed outside of the above described field body in the radial direction. A commutator secured to the armature body has a number of segments to which the coils are respectively connected. The motor has a power supplying part for supplying a current to the coils and a brush holder which is secured to the field body. The brush holder contains an anode side brush device which makes contact with and slides against the commutator and the power supplying part and a cathode side brush device which makes contact with and slides against the commutator and the power supplying part. Accordingly, the efficiency of use of the coils can be increased.

Abstract: A motor includes a stator having magnets, a rotor having teeth, a commutator secured to the rotor, and brushes. A coil is wound about each tooth. The commutator is connected to the coils. The brushes slidably contact the commutator. The number of the magnets and the number of the teeth are determined such that the resultant of torque vectors that act on the teeth is zero. For example, the number of the magnet is six, and the number of the teeth is eight. As a result, the rotor is prevented from vibrating.

Abstract: A commutator has a tabular holding portion defining a thickness direction. A plurality of segments are arranged in one end in the thickness direction of the holding portion in a radial pattern. Each of the segments has a slidable contact surface which is perpendicular to the thickness direction. A feeding brush is brought into slidable contact with the slidable contact surface. A tabular short-circuit unit short-circuits the segments to be set to the same electric potential with each other. The short-circuit unit is arranged parallel to the slidable contact surface. Accordingly, it is possible to enlarge a cross-sectional area which is perpendicular to a current passing direction of the coupling portion while suppressing an enlargement of a dimension in the axial direction of the commutator.

Abstract: A commutator connected to armature coils includes circumferentially arranged segments, short-circuit conductors, and a surge absorbing element. The number of the segments is a multiple of the number of the armature coils. The segments include a plurality of pairs of segments. The segments in each pair are adjacent to each other in the circumferential direction. Each segment in each pair is connected to one of the ends of corresponding one of the armature coils. The number of the short-circuit conductors is the same as the number of the armature coils. Each short-circuit conductor short-circuits segments that are at the same potential to each other. Each short-circuit conductor is connected, either directly or via corresponding one of the segments, to the surge absorbing element, so that the surge absorbing element is electrically interposed between the ends of each armature coil.

Abstract: A motor has a plurality of excitation coils, a commutator having a plurality of segments, a plurality of supply brushes and a short-circuit line. Each coil is connected to corresponding ones of the segments. The supply brushes include a plurality of supply brushes each having one of an anode and a cathode. At least one supply brush has the other one of an anode and a cathode. The supply brushes each simultaneously contact different one of the segments. The short-circuit line short-circuits segments that simultaneously contact the supply brushes of the same pole. The supply brushes of the same pole separate from the short-circuited segments at different times.

Abstract: A core includes a ring body and a plurality of teeth. The teeth extend radially outward form the outer circumference of the ring body. The core is formed by assembling a first core member and a second core member. Each core member has part of the teeth the number of which is half the total number of the teeth. Each tooth includes a tooth body about which the coil is wound, and a magnetism converging portion provided at the distal end of the tooth body. The tooth height of each tooth body gradually increases from a distal section to a proximal section of the tooth body. The tooth width gradually decreases from the distal section to the proximal section. The wire is wound about each of the teeth of the first and second core members. Then, the first and second core members are assembled to form the core. Accordingly, a rotor core having a high coil accommodation efficiency and a high coil space factor is obtained.

Abstract: A stator of a direct current motor includes six magnetic poles. An armature of the direct current motor includes an armature core having eight slots, a plurality of windings wound around the armature core as concentrated windings, and a commutator having twenty-four segments connected to the windings. The plurality of windings are connected to one another to form a single closed loop. The direct current motor further includes an anode power supply brush and a cathode power supply brush that slidably contact the segments. The aspect ratio, which is the ratio of the diameter of the armature core with respect to the length in the axial direction of the armature core is set to a range of 3.2 through 5.6. This increases the constraint torque/mass ratio of the direct current motor.

Abstract: A motor has a plurality of excitation coils, a commutator having a plurality of segments, a plurality of supply brushes and a short-circuit line. Each coil is connected to corresponding ones of the segments. The supply brushes include a plurality of supply brushes each having one of an anode and a cathode. At least one supply brush has the other one of an anode and a cathode. The supply brushes each simultaneously contact different one of the segments. The short-circuit line short-circuits segments that simultaneously contact the supply brushes of the same pole. The supply brushes of the same pole separate from the short-circuited segments at different times.

Abstract: A motor has a plurality of excitation coils, a commutator having a plurality of segments, a plurality of supply brushes and a short-circuit line. Each coil is connected to corresponding ones of the segments. The supply brushes include a plurality of supply brushes each having one of an anode and a cathode. At least one supply brush has the other one of an anode and a cathode. The supply brushes each simultaneously contact different one of the segments. The short-circuit line short-circuits segments that simultaneously contact the supply brushes of the same pole. The supply brushes of the same pole separate from the short-circuited segments at different times.

Abstract: Teeth of a first core sub-part and teeth of a second core sub-part are alternately arranged in a circumferential direction. Each tooth has a tooth main body, which may include two tilted portions at two opposed circumferential ends, respectively, of the tooth main body. Each tilted portion is angled relative to a corresponding direction parallel to the axial direction of the core. Each one of the first and second core sub-parts may have fitting recesses and fitting projections, which are engaged with the fitting projections and the fitting recesses of the other one of the first and second core sub-parts. Each tapered wall surface of each fitting recess is angled relative to a corresponding direction parallel to the axial direction. Similarly, each tapered wall surface of each fitting projection is angled relative to a corresponding direction parallel to the axial direction.

Abstract: Teeth of a first core sub-part and teeth of a second core sub-part are alternately arranged in a circumferential direction. Each tooth has a tooth main body, which may include two tilted portions at two opposed circumferential ends, respectively, of the tooth main body. Each tilted portion is angled relative to a corresponding direction parallel to the axial direction of the core. Each one of the first and second core sub-parts may have fitting recesses and fitting projections, which are engaged with the fitting projections and the fitting recesses of the other one of the first and second core sub-parts. Each tapered wall surface of each fitting recess is angled relative to a corresponding direction parallel to the axial direction. Similarly, each tapered wall surface of each fitting projection is angled relative to a corresponding direction parallel to the axial direction.

Abstract: A core includes a ring body and a plurality of teeth. The teeth extend radially outward form the outer circumference of the ring body. The core is formed by assembling a first core member and a second core member. Each core member has part of the teeth the number of which is half the total number of the teeth. Each tooth includes a tooth body about which the coil is wound, and a magnetism converging portion provided at the distal end of the tooth body. The tooth height of each tooth body gradually increases from a distal section to a proximal section of the tooth body. The tooth width gradually decreases from the distal section to the proximal section. The wire is wound about each of the teeth of the first and second core members. Then, the first and second core members are assembled to form the core. Accordingly, a rotor core having a high coil accommodation efficiency and a high coil space factor is obtained.

Abstract: Teeth of a first core sub-part and teeth of a second core sub-part are alternately arranged in a circumferential direction. Each tooth has a tooth main body, which may include two tilted portions at two opposed circumferential ends, respectively, of the tooth main body. Each tilted portion is angled relative to a corresponding direction parallel to the axial direction of the core. Each one of the first and second core sub-parts may have fitting recesses and fitting projections, which are engaged with the fitting projections and the fitting recesses of the other one of the first and second core sub-parts. Each tapered wall surface of each fitting recess is angled relative to a corresponding direction parallel to the axial direction. Similarly, each tapered wall surface of each fitting projection is angled relative to a corresponding direction parallel to the axial direction.

Abstract: Teeth of a first core sub-part and teeth of a second core sub-part are alternately arranged in a circumferential direction. Each tooth has a tooth main body, which may include two tilted portions at two opposed circumferential ends, respectively, of the tooth main body. Each tilted portion is angled relative to a corresponding direction parallel to the axial direction of the core. Each one of the first and second core sub-parts may have fitting recesses and fitting projections, which are engaged with the fitting projections and the fitting recesses of the other one of the first and second core sub-parts. Each tapered wall surface of each fitting recess is angled relative to a corresponding direction parallel to the axial direction. Similarly, each tapered wall surface of each fitting projection is angled relative to a corresponding direction parallel to the axial direction.

Abstract: Teeth of a first core sub-part and teeth of a second core sub-part are alternately arranged in a circumferential direction. Each tooth has a tooth main body, which may include two tilted portions at two opposed circumferential ends, respectively, of the tooth main body. Each tilted portion is angled relative to a corresponding direction parallel to the axial direction of the core. Each one of the first and second core sub-parts may have fitting recesses and fitting projections, which are engaged with the fitting projections and the fitting recesses of the other one of the first and second core sub-parts. Each tapered wall surface of each fitting recess is angled relative to a corresponding direction parallel to the axial direction. Similarly, each tapered wall surface of each fitting projection is angled relative to a corresponding direction parallel to the axial direction.

Abstract: A motor has twenty-four segments and a commutator. Each of eight short-circuit members short-circuits three of the segments with one another. Each short-circuit member includes an annular base portion and three arms radially extending from the base portion. Each arm is connected to one of the three segments to be short-circuited. Each arm has a segment connection portion at the distal end. The segment connection portion is connected to the corresponding segment. The base portions are laminated in the axial direction of the commutator such that the short-circuit members form a laminated body. The arms are formed such that all the segment connection portions are located in the same position with respect to the axial direction of the laminated body. As a result, the manufacture of the motor is facilitated.

Abstract: A motor includes a stator having magnets, a rotor having teeth, a commutator secured to the rotor, and brushes. A coil is wound about each tooth. The commutator is connected to the coils. The brushes slidably contact the commutator. The number of the magnets and the number of the teeth are determined such that the resultant of torque vectors that act on the teeth is zero. For example, the number of the magnet is six, and the number of the teeth is eight. As a result, the rotor is prevented from vibrating.

Abstract: A motor includes a stator having magnets, a rotor having teeth, a commutator secured to the rotor, and brushes. A coil is wound about each tooth. The commutator is connected to the coils. The brushes slidably contact the commutator. The number of the magnets and the number of the teeth are determined such that the resultant of torque vectors that act on the teeth is zero. For example, the number of the magnet is six, and the number of the teeth is eight. As a result, the rotor is prevented from vibrating.

Abstract: Teeth of a first core sub-part and teeth of a second core sub-part are alternately arranged in a circumferential direction. Each tooth has a tooth main body, which may include two tilted portions at two opposed circumferential ends, respectively, of the tooth main body. Each tilted portion is angled relative to a corresponding direction parallel to the axial direction of the core. Each one of the first and second core sub-parts may have fitting recesses and fitting projections, which are engaged with the fitting projections and the fitting recesses of the other one of the first and second core sub-parts. Each tapered wall surface of each fitting recess is angled relative to a corresponding direction parallel to the axial direction. Similarly, each tapered wall surface of each fitting projection is angled relative to a corresponding direction parallel to the axial direction.

Abstract: An armature includes a rotor core, winding wires, insulator arrangements and protective members. The rotor core includes a plurality of teeth, each of which extends in a radial direction of the rotor core. Each winding wire is wound around a corresponding one of the teeth. The insulator arrangements electrically insulate between the rotor core and the winding wires. The protective members are provided to the rotor core to protect the rotor core from mechanical damage.