Abstract: A short-circuit member assembly for short-circuiting a plurality of segments arranged in a circumferential direction is disclosed. The short-circuit member assembly includes first and second short-circuit member groups that are superimposed with each other. The first short-circuit member group includes m first terminals, which are superimposed and joined with m first terminals included in the second short-circuit member group to form m first-terminal joint portions. The m first-terminal joint portions and the remaining first terminals in the short-circuit member groups are arranged in the circumferential direction and connected to the segments. All of the second terminals in the first short-circuit member group are superimposed and joined with all of the second terminals included in the second short-circuit member group.

Abstract: A direct current motor is disclosed. The motor includes a stator, a commutator, an armature core, and brushes. The stator has a yoke and magnetic poles. The magnetic poles are arranged at a predetermined pitch along a circumferential direction of the yoke. The number of the magnetic poles is represented by the expression: 2×P (P is an integer not less than 2). The commutator has segments that are arranged in a circumferential direction of the commutator. The number of the segments is represented by the expression: P×N (N is an odd number not less than 3). The armature core is rotatable integrally with the commutator and includes teeth provided by the number represented by the expression: 2×P×N. A coil is wound around the teeth by distributed winding. Each one of the brushes is pressed against and contacts the segments.

Abstract: A commutator main body has a cylindrical insulating body, and a plurality of segments arranged in an outer circumference of the insulating body. A short-circuit member is arranged in an end in an axial direction of the insulating body. The short-circuit member has a plurality of first short-circuit pieces and a plurality of second short-circuit pieces. A tabular insulating portion covers first coupling portions of the first short-circuit pieces, and second coupling portions of the second short-circuit pieces. The insulating portion has a restriction recess, and the end in the axial direction has a restriction projection. The restriction projection is engaged with the restriction recess, whereby the movement of the short-circuit member in the circumferential direction with respect to the commutator main body is restricted. Accordingly, the assembly of the short-circuit member in the commutator main body is facilitated.

Abstract: In a direct current electric motor, segment pieces of a commutator are generally planar and are arranged one after another in a circumferential direction about a rotational axis of the commutator. A slidably engaging surface of each segment piece, which is slidably engageable with a plurality of brushes of the motor, extends in a plane that is generally perpendicular to the rotational axis, and each segment piece includes a radially inner engaging portion at a radially inner end part of the segment piece. Each conductive line extends along a corresponding straight line and electrically interconnects between the radially inner engaging portions of corresponding two of the plurality of segment pieces to implement the same electric potential in the corresponding two of the plurality of segment pieces.

Abstract: A stator has four or more magnetic poles. A commutator has a plurality of segments arranged in the circumferential direction and a short-circuit conductor for short-circuiting predetermined segments from among these segments. Each segment has an angular width WS, and there is a gap of an angular width WU between the segments. A substantial angular width WB of each of an anode brush and a cathode brush satisfies (n?1)(WS+WU)+WU<WB<n(WS+WU)+WU, where n is an integer no less than two. A plurality of coils are each connected to the corresponding one of the segments in order to form n closed loops. The closed loops each pass through the corresponding segments and are electrically independent of each other.

Abstract: Ferromagnetic bodies, the number of which is n (n is an integer greater than or equal to two), are secured to an inner circumferential surface of a cylindrical yoke. A first gap S1 is provided between ferromagnetic bodies that are adjacent to each other in the circumferential direction. Active magnetic poles, the number of which is m (m is an integer greater than or equal to two), apply magnetic fields to each ferromagnetic body from radially inside. As a result, each magnet has magnetic pole portions the number of which is m. A third gap is provided between each pair of the active magnetic poles that correspond to a common ferromagnetic body. The angular width of the third gap is set greater than a first angular width of the first gap. As a result, all magnetic pole centers are easily arranged at equal angular intervals.

Abstract: A motor includes an annular armature core, a cylindrical yoke, and a permanent magnet that is fixed to the yoke in such a manner as to face the armature core in the radial direction. A plate-like magnetism guiding portion is located between the armature core and the permanent magnet. The magnetism guiding portion is made of a soft magnetic material, and has a first surface facing the permanent magnet and a second surface facing the armature core. With respect to the axial direction of the motor, the length of the first surface is equal to that of the permanent magnet, and the length of the second surface is less than that of the first surface With respect to the axial direction of the motor, the length of the permanent magnet is greater than that of the armature core.

Abstract: Coils are provided on a plurality of tooth sections of a core. The coils are formed by successively winding a conductor on the tooth sections with at least one tooth section between each successive windings, such that each portion of the conductor extending between two tooth sections located with at least one tooth section therebetween forms a jumper wire extending in the circumferential direction of the core. A commutator has a plurality of claw portions projecting to the outside of the commutator. Each of the claw portions electrically connects one of a plurality of segments to one of the jumper wires. When the core and the commutator are attached to a rotary shaft, each claw portion is arranged at a position corresponding to one of the jumper wires as viewed in the axial direction of the rotary shaft.

Abstract: In a process of producing a SiC device, a Si layer is formed on the surface of a SiC substrate, and the Si layer is removed from the surface of the SiC substrate by supplying oxygen gas to the Si layer in a high ambient temperature and a low ambient pressure. The pressure is set at 1×10−2 to 1×10−6 Pa. Thus a cleaned surface of the SiC substrate, not contaminated by carbon and the like in atmospheric air, can be provided. Preferably, the oxygen pressure and temperature are set at about 10−6 Pa and 1000° C. for removing the Si layer. Thereafter, the oxygen is further supplied to raise the pressure to about 104 Pa to form an oxide film on the cleaned SiC substrate. Thus, the SiC substrate is cleaned and then formed with the oxide layer in the same chamber by changing the ambient pressure but without changing the ambient temperature.

Abstract: In a process of producing a SiC device, a Si layer is formed on the surface of a SiC substrate, and the Si layer is removed from the surface of the SiC substrate by supplying oxygen gas to the Si layer in a high ambient temperature and a low ambient pressure. The pressure is set at 1×10−2 to 1×10−6 Pa. Thus a cleaned surface of the SiC substrate, not contaminated by carbon and the like in atmospheric air, can be provided. Preferably, the oxygen pressure and temperature are set at about 10−6 Pa and 1000° C. for removing the Si layer. Thereafter, the oxygen is further supplied to raise the pressure to about 104 Pa to form an oxide film on the cleaned SiC substrate. Thus, the SiC substrate is cleaned and then formed with the oxide layer in the same chamber by changing the ambient pressure but without changing the ambient temperature.

Abstract: A polymer having a blocked terminal group according to the present invention, represented by the following Formula (I): ##STR1## where R is an alkylene group containing 1 to 20 carbon atoms; X.sub.1 is an acyl group containing 2 to 50 carbon atoms; Y is H, an alkyl group containing 1 to 50 carbon atoms or an alkenyl group containing 1 to 50 carbon atoms; m is a positive integer; and n.sub.1 is 0 or a positive integer.

Abstract: A polymer having a blocked terminal group according to the present invention, represented by the following Formula (I): ##STR1## where R is an alkylene group containing 1 to 20 carbon atoms; X.sub.1 is an acyl group containing 2 to 50 carbon atoms; Y is H, an alkyl group containing 1 to 50 carbon atoms or an alkenyl group containing 1 to 50 carbon atoms; m is a positive integer; and n.sub.1 is 0 or a positive integer.