Patent ID: 7839030
Filing Date: 2010-11-23
Classification: H02K

Abstract:
1. A linear motor which includes a stator and a movable element, comprising: an armature disposed on one of the stator and the movable element, the armature including: a plurality of permanent magnet magnetic pole rows disposed on the other of the stator and the movable element, the permanent magnet magnetic pole rows each including: a plurality of the permanent magnets disposed at one side ends of the plurality of permanent magnet magnetic pole rows are different in length from one another as measured in the moving direction, and an average length of the permanent magnets disposed at the one side ends is defined as W a plurality of the permanent magnets disposed at the other side ends of the plurality of permanent magnet magnetic pole rows are different in length from one another as measured in the moving direction, and an average length of the permanent magnets disposed at the other side ends is defined as W the average length W the number of slots per pole per phase is ⅜, three-eighths; and when a pitch between centers of two adjacent magnetic pole portions of the plurality of magnetic pole portions constituting the armature is defined as τs, the length W of the permanent magnet is defined as W=τs; a ratio W