# US 10,308,307 B2 · Disk-type electric motor, electrically driven vehicle and method for controlling the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,307 B2 - Document ID: US10308307B2 - Status: Granted - Kind: B2 - Application number: 15/429,189 - Filed: 2017-02-10 - Published: 2017-08-17 - Granted: 2019-06-04 - Earliest claimed: 2016-02-16 - Assignees: Allied Treasure Inc, Limited - Applicants: Allied Treasure Inc, Limited - Inventors: Chi-Hsueh Richard - Web page: https://patentgrep.com/patent/US10308307B2 ## CPC - B62M 7/02: with engine between front and rear wheels - B62K 11/04: characterised by the engine being between front and rear wheels - H02K 1/02: characterised by the magnetic material - H02K 7/006: {Structural association of a motor or generator with the drive train of a motor vehicle} - H02K 11/33: Drive circuits, e.g. power electronics (H02K11/38 takes precedence) - H02K 21/16: having annular armature cores with salient poles (with homopolar co-operation H02K21/20) - H02K 21/24: with magnets axially facing the armatures, e.g. hub-type cycle dynamos - H02P 6/182: using back-emf in windings - H02P 6/26: Arrangements for controlling single phase motors - B62K 2202/00: Motorised scooters - B62K 2204/00: Adaptations for driving cycles by electric motor - H02K 2201/03: Machines characterised by aspects of the air-gap between rotor and stator - B62M: RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR {SINGLE-TRACK} CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES (arrangements or mounting of transmissions in vehicles in general B60K; transmission elements per se F16) - B62K: CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDECARS, FORECARS, OR THE LIKE - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract The present disclosure relates to a disk-type brushless direct current (BLDC) motor, which comprises a magnetic rotor and a stator. The magnetic rotor is provided with a rim and a plurality of equally spaced magnetic poles around the rim in circumferential direction. The stator is provided with a stator core having tooth portions and boot portions and a plurality of coil windings wrapped around the tooth portions. The stator is disposed radially in relation to the magnetic rotor such that the magnetic poles are radially polarized to produce radial magnetic flux density, and the magnetic flux density is substantially higher at both edges than middle portion of each magnetic pole in the circumferential direction. ## Claims ### Claim 1 A disk-type electric motor, comprising: a magnetic rotor having a rim and a plurality of equally spaced magnetic poles around the rim; and a stator having a stator core that includes tooth portions and boot portions and a plurality of series connected coil windings, wherein the plurality of series connected coil windings are driven by a driving signal with a single phase control scheme to produce an electromagnetic field of alternating polarity, each of the magnetic poles comprises a permanent magnet, and a radial magnetic flux density of the permanent magnet on a radial outer surface of the permanent magnet is substantially higher at both edges than a middle portion along a circumferential direction of the magnetic rotor. ### Claim 2 (depends on 1) The disk-type electric motor of claim 1, wherein the radial magnetic flux density substantially higher at the both edges, than the middle portion induces, on the coil windings, a back electromotive force (emf) signal approximating to a square wave such that the back emf signal in conjunction with the driving signal with the single phase control scheme reduces power loss. ### Claim 3 (depends on 2) The disk-type electric motor of claim 2, further comprising: a control circuit to adjust a phase difference by which the driving signal leads ahead of the back emf signal. ### Claim 4 (depends on 1) The disk-type electric motor of claim 1 wherein the boot portions are configured to sustain the radial magnetic, flux density at the both edges of the magnetic poles. ### Claim 5 (depends on 1) The disk-type electric motor of claim 1, wherein the number of the coil windings is equal to that of the magnetic poles. ### Claim 6 (depends on 1) The disk-type electric motor of claim 1, wherein each of the boot portions has a first air gap on a first pan and a second air gap which is larger than the first air gap on a second part from the magnetic poles, the second part having shorter arc length than the first part. ### Claim 7 (depends on 1) The disk-type electric motor of claim 1, wherein the magnetic poles are provided with R—Fe—B magnets, R being rare-earth metals, Fe being iron, B being boron. ### Claim 8 (depends on 1) The disk-type electric motor of claim 1, wherein a radial diameter of the magnetic rotor is larger than an axial thickness thereof. ### Claim 9 An electrically driven vehicle, comprising: at least two wheels; a single-phase control circuit; and a disk-type electric motor, further comprising: a magnetic rotor having a rim and a plurality of equally spaced magnetic poles around the rim; and a stator having a stator core that includes tooth portions and boot portions and a plurality of series connected coil windings, wherein the plurality of series connected coil windings are driven by a driving signal generated by the single-phase control circuit to produce an electromagnetic field of alternating polarity, wherein each of the magnetic poles comprises a permanent magnet, and a radial magnetic flux density of the permanent magnet on a radial outer surface of the permanent magnet is substantially higher at both edges than a middle portion along a circumferential direction of the magnetic rotor. ### Claim 10 (depends on 9) The electrically driven vehicle of claim 9, wherein the radial magnetic flux density substantially higher at the both edges than the middle portion induces, on the coil windings, a back electromotive force (emf) signal approximating to a square wave such that the back emf signal in conjunction with the driving signal generated by the single-phase control circuit reduces power loss. ### Claim 11 (depends on 10) The electrically driven vehicle of claim 10, wherein the single-phase control circuit is further configured to adjust a phase difference by which the driving signal leads ahead of the back emf signal. ### Claim 12 (depends on 9) The electrically driven vehicle of claim 9, wherein the number of the coil windings is equal to that of the magnetic poles. ### Claim 13 (depends on 9) The electrically driven vehicle of claim 9, wherein the boot portions are configured to sustain the radial magnetic flux density at the both edges of the magnetic poles. ### Claim 14 (depends on 9) The electrically driven vehicle of claim 9, wherein each of the boot portions has a first air gap on a first part and a second air gap which is larger than the first air gap on a second part from the magnetic poles, the second part having shorter arc length than the first part. ### Claim 15 (depends on 9) The electrically driven vehicle of claim 9, wherein the magnetic poles are provided with R—Fe—B magnets, R being rare-earth metals, Fe being iron, B being boron. ### Claim 16 (depends on 9) The electrically driven vehicle of claim 9, wherein a radial diameter of the magnetic rotor is larger than an axial thickness thereof. ### Claim 17 A method for controlling a disk-type electric motor, wherein the BLDC motor includes a magnetic rotor having a rim and a plurality of equally spaced magnetic poles around the rim and a stator having a stator core that includes tooth portions and boot portions and a plurality of series connected coil windings, the method comprising: with a single phase control scheme, providing a driving signal for driving the plurality of series connected coil windings; in response to the driving signal, producing an electromagnetic field of alternating polarity; and via an interaction of the electromagnetic field with a radial magnetic flux density of the magnetic poles, rotating the magnetic rotor, wherein each of the magnetic poles comprises a permanent magnet, and the radial magnetic flux density of the permanent magnet on a radial outer surface of the permanent magnet is substantially higher at both edges than a middle portion along a circumferential direction of the magnetic rotor. ### Claim 18 (depends on 17) The method of claim 17, wherein a back electromotive force (emf) signal is induced on the coil windings, which approximates to a square wave such that the back emf signal in conjunction with the driving signal reduces power loss. ### Claim 19 (depends on 18) The method of claim 18, further comprising adjusting, by a control circuit, a phase difference by which the driving signal leads ahead of the back emf signal. ### Claim 20 (depends on 17) The method of claim 17, further comprising changing an input power to the disk-type electric motor by modulating a duty time of the driving signal with a pulse width modulation module.