# US 10,312,771 B2 · Brushless motor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,771 B2 - Document ID: US10312771B2 - Status: Granted - Kind: B2 - Application number: 15/286,926 - Filed: 2016-10-06 - Published: 2017-05-18 - Granted: 2019-06-04 - Earliest claimed: 2015-11-13 - Assignees: Tokyo Parts Industrial Co., Ltd. - Applicants: Tokyo Parts Industrial Co., Ltd. - Inventors: Masahiro Nishidate - Web page: https://patentgrep.com/patent/US10312771B2 ## CPC - H02K 7/085: {radially supporting the rotary shaft at only one end of the rotor (H02K7/086, H02K7/09 take precedence)} - H02K 5/1675: {radially supporting the rotary shaft at only one end of the rotor (H02K5/1677 takes precedence)} - H02K 21/16: having annular armature cores with salient poles (with homopolar co-operation H02K21/20) - H02K 21/22: with magnets rotating around the armatures, e.g. flywheel magnetos - H02K 2205/03: Machines characterised by thrust bearings - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract The bottom end of a rotary shaft contacts a cover part of a cover member, while the top end of the rotary shaft protrudes upwards from a retaining plate. A planar first washer member, which is made from a hard material, is fastened to the rotary shaft, between a bottom plate of a rotor case and an oil-impregnated bearing. The first washer member is disposed without contact with the bottom plate of the rotor case and the oil-impregnated bearing. ## Claims ### Claim 1 A brushless motor comprising: a bearing holder having a first cylindrical portion; an oil-impregnated bearing fastened to the inner circumferential face of the bearing holder; a rotary shaft supported by the oil-impregnated bearing so as to be rotatable around a vertically oriented central axis; a rotor having a rotor case, which is fastened to the rotary shaft, and a rotor magnet, the rotor case having a second cylindrical portion and a bottom plate portion, the bottom plate portion closing a bottom end of the second cylindrical portion, and the rotor magnet fastened to a circumferential face of the rotor case; a stator, arranged so as to face the rotor magnet in a radial direction; a retaining plate that extends radially outward from a top of the first cylindrical portion; and a cover member, which has a third cylindrical portion and a cover portion that closes a bottom end of the third cylindrical portion, a top end of the third cylindrical portion being fastened directly to the retaining plate, so as to cover the rotor and the stator, wherein: a bottom end of the rotary shaft contacts the cover member and a top end of the rotary shaft protrudes upward from the retaining plate; a first washer member, which is made from a hard material and has a flat face, is fastened to the rotary shaft, between the bottom plate portion and the oil-impregnated bearing; and the first washer member is disposed without contact with the bottom plate portion and the oil-impregnated bearing. ### Claim 2 (depends on 1) The brushless motor according to claim 1, wherein a burring part, which fastens the rotary shaft, rises upward in the center or the bottom plate portion; and the first washer member is disposed without contact with a top end of the burring part. ### Claim 3 (depends on 2) The brushless motor according to claim 2, wherein: a second washer member, which is made from a soft material and has a flat face, is provided on the rotary shaft, between the first washer member and the oil-impregnated bearing; and the second washer member is disposed without contact with the oil-impregnated bearing. ### Claim 4 (depends on 3) The brushless motor according to claim 3, wherein the outer diameters of the first washer member and the second washer member are smaller than the inner diameter of the first cylindrical portion. ### Claim 5 (depends on 1) The brushless motor according to claim 1, wherein: the rotor magnet is fastened to an inner circumferential face of the second cylindrical portion; the stator has a stator core fastened to an outer circumferential face of the first cylindrical portion; and the stator core is disposed facing an inner circumferential face of the rotor magnet in a radial direction. ### Claim 6 (depends on 2) The brushless motor according to claim 2, wherein: the rotor magnet is fastened to an inner circumferential face of the second cylindrical portion; the stator has a stator core fastened to an outer circumferential face of the first cylindrical portion; and the stator core is disposed facing an inner circumferential face of the rotor magnet in a radial direction. ### Claim 7 (depends on 3) The brushless motor according to claim 3, wherein the rotor magnet is fastened to an inner circumferential face of the second cylindrical portion; the stator has a stator core fastened to an outer circumferential face of the first cylindrical portion; and the stator core is disposed facing an inner circumferential face of the rotor magnet in a radial direction. ### Claim 8 (depends on 4) The brushless motor according to claim 4, wherein: the rotor magnet is fastened to an inner circumferential face of the second cylindrical portion; the stator has a stator core fastened to an outer circumferential face of the first cylindrical portion; and the stator core is disposed facing an inner circumferential face of the rotor magnet in a radial direction. ### Claim 9 (depends on 1) The brushless motor according to claim 1, wherein the top end of the third cylindrical portion is fastened in direct contact to an outer circumference of the retaining plate, so that the retaining plate covers the rotor magnet, the second cylindrical portion, and the stator.