Miniature electric motor having bearing unit

• Main Authors: HARANO, JUNICHI, IWAMOTO, SHIGEYOSHI, KASE, MITSUO
• Format: Patent
• Language: English; French; German
• Published: 29.12.1997
• Edition: 6
• Subjects: BEARINGS; BLASTING; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; DYNAMO-ELECTRIC MACHINES; ELECTRICITY; ELEMENTS OR CRANKSHAFT MECHANISMS; ENGINEERING ELEMENTS AND UNITS; FLEXIBLE SHAFTS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; GENERATION; HEATING; LIGHTING; MECHANICAL ENGINEERING; ROTARY BODIES OTHER THAN GEARING ELEMENTS; SHAFTS; THERMAL INSULATION IN GENERAL; WEAPONS

A miniature electric motor has a rotor (34) arranged within a casing (31) within which a stator (32) is mounted. A rotary shaft (35) of the rotor is supported by bearing units (36, 37) mounted on spaced ends of the casing. One (37) of the bearing units is provided with a thrust receiving member (51) for supporting an end portion (57) of the rotary shaft in a thrust direction, and a bearing (53) for supporting the rotary shaft in a radial direction within a rotary shaft insertion hole (52). The thrust receiving member has a dimension which is equal to or smaller than an inner diameter of a closed recess (39) formed in the casing and is laid on a substantially planar base surface (54) of the recess. The bearing is securely fixed within the recess in abutment against the thrust receiving member. The rotary shaft insertion hole (52) is in fluid communication with a through-hole (56) formed through the base (55) of said recess. Thus, it is possible to shorten the axial length of the motor and to stably support the rotary shaft whilst preventing deformation of the thrust receiving member. it is also possible to ventilate air when the rotary shaft is inserted into the insertion hole of the bearing impregnated with lubricating oil.