Abstract: A rotor of a starter that employs an SR motor is directly connected to a crank shaft of an engine. The rotor and the crank shaft are set in such a way that when a piston is positioned at a top dead center or the like, salient poles and of the rotor face U-phase poles, so that an output torque of the starter comes to its maximum at a maximum pass-over torque position of the engine. When the engine is stopped, electricity is supplied through U-phase coils, thereby making the salient poles and the U-phase poles stop so as to face each other. In this manner, the piston is stopped at the maximum pass-over torque position. When the engine is started, electricity is supplied to W-phase coils which are adjacent to the U-phase coils, thereby making it possible to overcome a maximum friction torque with maximum outputs.

Abstract: A rotor of a starter that employs an SR motor is directly connected to a crank shaft of an engine. The rotor and the crank shaft are set in such a way that when a piston is positioned at a top dead center or the like, salient poles and of the rotor face U-phase poles, so that an output torque of the starter comes to its maximum at a maximum pass-over torque position of the engine. When the engine is stopped, electricity is supplied through U-phase coils, thereby making the salient poles and the U-phase poles stop so as to face each other. In this manner, the piston is stopped at the maximum pass-over torque position. When the engine is started, electricity is supplied to W-phase coils which are adjacent to the U-phase coils, thereby making it possible to overcome a maximum friction torque with maximum outputs.

Abstract: An electric power steering system 1 uses a brushless motor 3 as a drive source. The brushless motor 3 includes a stator 13 in which stator coils 17 are wound in a distributed manner and a rotor 14 rotatably disposed inside the stator 13. In the rotor 14, four sets of slit groups 31 each having circular-arc shaped slits 31a to 31c are formed. Rotor magnets 32 which are bonded magnets are filled in the slits 31a to 31c. The rotor magnets 32 are polar anisotropically magnetized. The rotor 14 is rotated by a magnet torque generated by the rotor magnets 32 and a reluctance torque based on a difference in inductance between magnetic paths so as to supply a steering assist force.

Abstract: A rotor includes S-pole and N-pole magnets which are arc-shaped in cross-section. Each pole has three magnets. Each magnet is embedded in the rotor in such a way that a convex side portion thereof faces center Or of the rotor. Distance Rs between center Os of circular arcs of S-pole magnets and center Or of the rotor is different from distance Rn between center On of circular arcs of N-pole magnets and center Or of the rotor (Rs?Rn). The ratio of the two distances is 0.92 (Rs/Rn=0.92). An outer peripheral section of an innermost-layer S-pole magnet is disposed in such a way as to protrude into an adjacent pole zone N1 or N2 from a pole zone S1 or S2.

Abstract: A control device 50 that drives and controls a brushless motor 3 of a four-pole 24-slot configuration includes: a base current calculation section 52 that calculates fundamental-wave current indicating a winding current value associated with maximum torque control; a correction component calculation section 59 that calculates 12th-order first higher harmonic wave component B sin 12(?+?) to cancel a torque ripple of magnet torque, and 12th-order second higher harmonic wave component A sin 12(?+?) to cancel a torque ripple of reluctance torque, based on a phase current value detected by a current sensor 64; a correction map 58 in which relation between phase current and parameters A, B, ?, and ? of the both higher harmonic wave components is stored; and a current correction section 60 that corrects supply current by superimposing each 12th-order higher harmonic wave component on the fundamental-wave current in order to create current command values Id? and Iq?.

Abstract: A brushless motor (1) includes a stator (2) including a stator core (5) formed by laminating a plurality of stator core plates (17), and a rotor (3) including a rotor core (15) formed by laminating a plurality of rotor core plates (18). The rotor core (15) includes a core body (15a), a magnet mounting hole (31) in which a magnet (16) is housed, and a salient pole portion (32) formed on an outer peripheral side of the magnet (16). An axial direction length Lr of the rotor core (15) is longer than an axial direction length Lm of the magnet (16) (Lr>Lm). A first overhang portion (41) is formed on both end portions of the rotor core (15). An axial direction length Ls of the stator core (5) is longer than the axial direction length Lr of the rotor core (15) (Ls>Lr). A second overhang portion (42) is formed on both end portions of the stator core (5).

Abstract: A control device 50 that drives and controls a brushless motor 3 of a four-pole 24-slot configuration includes: a base current calculation section 52 that calculates fundamental-wave current indicating a winding current value associated with maximum torque control; a correction component calculation section 59 that calculates 12th-order first higher harmonic wave component B sin 12(?+?) to cancel a torque ripple of magnet torque, and 12th-order second higher harmonic wave component A sin 12(?+?) to cancel a torque ripple of reluctance torque, based on a phase current value detected by a current sensor 64; a correction map 58 in which relation between phase current and parameters A, B, ?, and ? of the both higher harmonic wave components is stored; and a current correction section 60 that corrects supply current by superimposing each 12th-order higher harmonic wave component on the fundamental-wave current in order to create current command values Id? and Iq?.

Abstract: A rotor includes S-pole and N-pole magnets which are arc-shaped in cross-section. Each pole has three magnets. Each magnet is embedded in the rotor in such a way that a convex side portion thereof faces center Or of the rotor. Distance Rs between center Os of circular arcs of S-pole magnets and center Or of the rotor is different from distance Rn between center On of circular arcs of N-pole magnets and center Or of the rotor (Rs?Rn). The ratio of the two distances is 0.92 (Rs/Rn=0.92). An outer peripheral section of an innermost-layer S-pole magnet is disposed in such a way as to protrude into an adjacent pole zone N1 or N2 from a pole zone S1 or S2.

Abstract: It is aimed to provide a connector terminal including a tin layer on an outermost surface and a material therefor which achieves a low insertion force without depending on the detail of the microstructure of the outermost surface and excessively increasing a contact resistance. A composite coating layer including areas where tin is exposed and areas where a copper-tin alloy is exposed on an outermost surface is formed on a surface of a base material in an area including a contact portion to be brought into contact with another electrically conductive member and the glossiness of the surface of the composite coating layer is in a range of 50 to 1000%.

Abstract: It is aimed to provide a plated terminal for connector and a terminal pair having a tin layer on an outermost surface and achieving both a reduction of a terminal insertion force and a reduction of a contact resistance. The plated terminal for connector includes a coating layer containing tin and a hard metal harder than tin at a contact portion to be brought into contact with another electrical conductive member, and both an area where tin is exposed on an outermost surface and an area where the hard metal is exposed on the outermost surface or an area where the hard metal is coated with a tin layer thinner than in other parts are included in the contact portion. Such a material can be obtained, for example, by forming a tin layer on a surface of a base material having an uneven structure on a surface of which a hard metal layer is formed.

Abstract: A control device (50) for an IPM-type brushless motor (3) includes a fundamental-current calculating section (52) for calculating fundamental-wave currents indicating winding current values to be set in maximum-torque control, a correction-component calculating section (59) for calculating a first harmonic component (B sin 6(?+?)) for cancelling a torque ripple for a magnet torque and a second harmonic component (A sin 6(?+?)) for cancelling a torque ripple for a reluctance torque based on phase-current values detected by a current sensor (64), a correction map (58) storing relationships between the phase currents and parameters (A, B, ?, and ?) of the first harmonic component and the second harmonic component, and a current-correcting section (60) for superimposing the first harmonic component and the second harmonic component respectively on the fundamental-wave currents to correct a current to be supplied so as to generate current command values (Id? and Iq?).

Abstract: A brushless motor has a 2P3S×n structure, in which a ratio (W) of a circumferential width (Wm) of each of magnets to a length (Wp) of a chord formed between endpoints of an arc with a center angle ?p=360°/pole-number 3n, the arc being included in an inner-diameter circle C2 of each of the magnets, is in a range of 0.76<W=Wm/Wp<0.86. Therefore, in the brushless motor of the 2P3S×n structure, a skew angle may be set in a range of 36°??skew?57° in terms of electrical angle, while a content ratio of a fifth harmonic component contained in an induced voltage of the brushless motor may be set in a range of 4.5% to 6.5% with respect to a fundamental wave.

Abstract: In a brushless motor having a stator including armature windings for a plurality of phases, and a rotor including a permanent magnet and being rotatably disposed inside or outside of the stator, an inter-phase induced voltage waveform between two different phases in the armature windings is a trapezoidal waveform formed by superimposing a fifth-order component and a seventh-order component on a first-order fundamental wave. A content rate X(=(?5+?7)/?1) of a total of voltage peak values ?5 and ?7 of the fifth-order component and the seventh-order component to a voltage peak value ?1 of the first-order fundamental wave is preferably set to a range of 0.01?X?0.1, and more preferably to a range of 0.02?X?0.09.

Abstract: In a brushless motor for an electric power steering device having a configuration of 2 poles and 3 slots, or of an integral multiple thereof, a stator coil is supplied with current containing a higher harmonic component. A difference of 0.5% to 1.5% is provided between the higher harmonic component content rate of the stator coil current and the higher harmonic component content rate of the induced electromotive force generated in the stator coil with rotation of a permanent magnet, thereby mitigating the influence by an armature reaction generated in the induced electromotive force to reduce torque ripples. The difference between the higher harmonic component content rates is set on the basis of a change that occurs in the induced electromotive force due to the armature reaction at a time of supplying electricity to the armature coil.

Abstract: In a brushless motor including a rotor having 2n magnetic poles and a stator having 3n slots, the magnetic poles of the rotor are composed of segment magnets arranged in three columns extending in an axial direction. The magnets of each column are displaced from the magnet of either adjacent column in a circumferential direction, forming a 3-stage step-skew structure. The segment magnets have a skew angle ?skew ranging from 36° to 57° in terms of electrical angle.

Abstract: In a brushless motor including a rotor having 2n poles and a stator having 3n slots, segment magnets are arranged in three columns in the axial direction, thus constituting rotor poles. The segment magnets of adjacent columns, which are identical in polarity, are displaced in the circumferential direction, thus forming a three-stage step-skew structure. The skew angle ?skew of each segment magnet is set to an electrical angle of 60° to 75°. The center angle of ?m of each segment magnet is set to 46.8° to 52.7°.

Abstract: A brushless motor has rotor cores dividedly formed as plural sections in an axial direction, segment magnets secured to outer circumferential surfaces of the rotor cores, and magnet holders secured to the rotor cores, respectively, for holding the segment magnet. Each of the rotor cores has holder-positioning grooves to which holder arms are fitted, and bridge parts formed corresponding to the holder positioning grooves. Each of the magnet holders has joint grooves fitted in the bridge parts and displaced from the holder arms by a step angle, the bridge parts being fitted in the joint grooves, thereby assembling a rotor.

Abstract: Provided is a brushless motor of a 2P3S×n structure, in which a ratio (W) of a circumferential width (Wm) of each of magnets (16a to 16c) to a length (Wp) of a chord formed between endpoints of an arc with a center angle ?p=360°/pole-number 3n, the arc being included in an inner-diameter circle C2 of each of the magnets (16a to 16c), is in a range of 0.76<W=Wm/Wp<0.86. Therefore, in the brushless motor of the 2P3S×n structure, a skew angle may be set in a range of 36°??skew?57° in terms of electrical angle, while a content ratio of a fifth harmonic component contained in an induced voltage of the brushless motor may be set in a range of 4.5% to 6.5% with respect to a fundamental wave.

Abstract: A rack-assist type electric power steering device (10) uses a motor (1) as a drive source. The stator (11) of the motor (1) includes a stator core (13) having ring-like yoke portion (16) and teeth (17) projecting from the yoke portion (16) in the inner direction. In the stator core (13), the ratio (Wy:Wt) between the width (Wy) of the yoke portion (16) in the radial direction and the width (Wt) of the teeth (17) in the circumferential direction is 1:1.4 to 1.8.

Abstract: In a brushless motor having a stator including armature windings for a plurality of phases, and a rotor including a permanent magnet and being rotatably disposed inside or outside of the stator, an inter-phase induced voltage waveform between two different phases in the armature windings is a trapezoidal waveform formed by superimposing a fifth-order component and a seventh-order component on a first-order fundamental wave. A content rate X(=(?5+?7)/?1) of a total of voltage peak values ?5 and ?7 of the fifth-order component and the seventh-order component to a voltage peak value ?1 of the first-order fundamental wave is preferably set to a range of 0.01?X?0.1, and more preferably to a range of 0.02?X?0.09.