# US 2018/0026486 A1 · Bldc motor and cleaner having the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026486 A1 - Document ID: US20180026486A1 - Status: Published application - Kind: A1 - Application number: 15/547,174 - Filed: 2016-01-28 - Published: 2018-01-25 - Earliest claimed: 2015-01-28 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Changhum JO; Kyunghoon LEE; Kwangyong JANG; Jongwon KIM - Web page: https://patentgrep.com/patent/US20180026486A1 ## CPC - H02K 1/278: Surface mounted magnets; Inset magnets - A47L 9/22: Mountings for motor fan assemblies - H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - A47L: DOMESTIC WASHING OR CLEANING (brushes A46B; cleaning quantities of bottles or of other hollow articles of one kind B08B9/00; laundry D06F); SUCTION CLEANERS IN GENERAL (cleaning in general B08) ## Abstract A brushless direct current (BLDC) motor is disclosed. The BLDC motor includes a shaft made of a nonmagnetic material, a plurality of magnets surrounding the outer circumference of the shaft, a stator surrounding the outer circumferences of the magnets, wherein each of the magnets has an arc-shaped outer circumferential surface, an arc-shaped inner circumferential surface facing the shaft, and opposite side surfaces facing other adjacent magnets, and the magnets include a first magnet magnetized in a direction directed from the outer circumferential surface to the inner circumferential surface, a second magnet magnetized in a direction directed from the inner circumferential surface to the outer circumferential surface, and a third magnet magnetized in a direction directed from one side surface to the other side surface. The efficiency of the motor is improved while eddy current loss is minimized. ## Claims ### Claim 1 A brushless direct current (BLDC) motor comprising: a shaft made of a nonmagnetic material; a plurality of magnets surrounding an outer circumference of the shaft; and a stator surrounding outer circumferences of the magnets, wherein: each of the magnets has: an outer circumferential surface; an inner circumferential surface facing the outer circumference of the shaft; and opposite side surfaces extending between the inner circumferential surface and the outer circumferential surface, each of the side surfaces facing an adjacent other one of the magnets, and the magnets include: a first magnet magnetized in a direction from the outer circumferential surface of the first magnet to the inner circumferential surface of the first magnet; a second magnet magnetized in a direction from the inner circumferential surface of the second magnet to the outer circumferential surface of the second magnet; and a third magnet magnetized in a direction from one of the side surfaces of the third magnet to another of the side surfaces of the third magnet. ### Claim 2 (depends on 1) The BLDC motor according to claim 1, wherein the first magnet and the second magnet are positioned on opposite radial directions of the shaft is. ### Claim 3 (depends on 1) The BLDC motor according to claim 1, wherein the third magnet is located between the first magnet and the second magnet in a circumferential direction. ### Claim 4 (depends on 3) The BLDC motor according to claim 3, wherein the third magnet includes a plurality of third magnets provided along the outer circumference of the shaft between the first magnet and the second magnet. ### Claim 5 (depends on 2) The BLDC motor according to claim 2, wherein: the third magnet is included in: a first plurality of third magnets positioned between the first magnet and the second magnet in a first circumferential direction of the shaft, and a second plurality of third magnets positioned between the first magnet and the second magnet in a second circumferential direction of the shaft that is opposite to the first circumferential direction, and the first plurality of third magnets are magnetized in the first circumferential direction toward the second magnet, and the second plurality of third magnets are magnetized in the second circumferential direction toward the second magnet. ### Claim 6 (depends on 1) The BLDC motor according to claim 1, wherein each of the magnets is configured such that an angle between a first extension line connecting from a center of rotation of the shaft to the one side surface and a second extension line connecting from the center of rotation of the shaft to the other side surface is one of 36 degrees, 45 degrees, or 60 degrees. ### Claim 7 (depends on 1) The BLDC motor according to claim 1, further comprising a sleeve surrounding the magnets, the sleeve being made of carbon fiber. ### Claim 8 (depends on 1) The BLDC motor according to claim 1, wherein the shaft is made of stainless steel (STS). ### Claim 9 A cleaner comprising: a brushless direct current (BLDC) motor having a shaft; an impeller mounted at the shaft; and an impeller cover surrounding the impeller, the impeller cover being configured to guide air driven by the impeller into the BLDC motor, wherein: the BLDC motor includes: a plurality of magnets surrounding an outer circumference of the shaft; and a stator surrounding outer circumferences of the magnets, each of the magnets has: an outer circumferential surface; an inner circumferential surface facing the shaft; and opposite side surfaces extending between the inner circumferential surface and the outer circumferential surface, each of the side surfaces facing an adjacent other one of the magnets, and the magnets include: a first magnet magnetized in a direction from the outer circumferential surface of the first magnet to the inner circumferential surface of the first magnet; a second magnet magnetized in a direction from the inner circumferential surface of the second magnet to the outer circumferential surface of the second magnet; and a third magnet magnetized in a direction from one of the side surfaces of the third magnet to another of the side surfaces of the third magnet. ### Claim 10 (depends on 9) The cleaner according to claim 9, wherein the first magnet and the second magnet are positioned on opposite radial directions of the shaft. ### Claim 11 (depends on 9) The cleaner according to claim 9, wherein the third magnet is located between the first magnet and the second magnet in a circumferential direction. ### Claim 12 (depends on 11) The cleaner according to claim 11, wherein the third magnet includes a plurality of third magnets arranged along the outer circumference of the shaft. ### Claim 13 (depends on 9) The cleaner according to claim 9, wherein: the third magnet includes: a first plurality of third magnets positioned between the first magnet and the second magnet in a first circumferential direction of the shaft, and a second plurality of third magnets positioned between the first magnet and the second magnet in a second circumferential direction of the shaft that is opposite to the first circumferential direction, and the first plurality of third magnets are magnetized in the first circumferential direction toward the second magnet, and the second plurality of third magnets are magnetized in the second direction toward the second magnet. ### Claim 14 (depends on 9) The cleaner according to claim 9, wherein each of the magnets is configured such that an angle between a first extension line connecting from a center of rotation of the shaft to the one side surface and a second extension line connecting from the center of rotation of the shaft to the other side surface is one of 36 degrees, 45 degrees, or 60 degrees. ### Claim 15 (depends on 9) The cleaner according to claim 9, wherein the BLDC motor further includes a sleeve surrounding the magnets, the sleeve being made of carbon fiber. ### Claim 16 A brushless direct current (BLDC) motor comprising: a shaft made of a nonmagnetic material; a plurality of magnets extending around an outer circumference of the shaft; and a stator positioned around outer circumferences of the magnets, wherein the magnets include a first magnet and a second magnet that are positioned on opposite radial directions of the shaft, the first magnet is magnetized in a first direction that extends radially inward toward the shaft, and the a second magnet magnetized in a second direction the extends radially outward from the shaft. ### Claim 17 (depends on 16) The BLDC motor according to claim 16, wherein the magnets include a third magnet that is positioned between the first magnet and the second magnet in a circumferential direction, the third magnet being magnetized in a third direction that extends from the first magnet to the second magnet. ### Claim 18 (depends on 17) The BLDC motor according to claim 17, wherein the third magnet includes: a first plurality of third magnets positioned between the first magnet and the second magnet in a first circumferential direction of the shaft, and a second plurality of third magnets positioned between the first magnet and the second magnet in a second circumferential direction of the shaft that is opposite to the first circumferential direction, the first plurality of third magnets being magnetized in the first circumferential direction toward the second magnet, and the second plurality of third magnets being magnetized in the second circumferential direction toward the second magnet. ### Claim 19 (depends on 17) The BLDC motor according to claim 17, wherein each of the first magnet, the second magnet, and the third magnet has a corresponding shape that includes: an arc-shaped outer circumferential surface; an arc-shaped inner circumferential surface facing the shaft; and opposing side surfaces extending between the inner circumferential surface and the outer circumferential surface. ### Claim 20 (depends on 16) The BLDC motor according to claim 16, further comprising a sleeve surrounding the magnets, the sleeve being made of carbon fiber.