Patent EP-0237778-A2 (EP)
Inventor: MARUYAMA TOSHIKI C O ISE FACTO
IPC: H02P8/14
Filed: 1987-02-11
Abstract: A pulse motor comprises primary side magnetic flux generator unit having a plurality of magnetic poles and a secondary side magnetic member provided rotatably in the primary side magnetic flux generator, characterized in the primary side magnetic flux generator unit generating a magnetic flux passing through a magnetic flux path formed by at least two of the magnetic poles and the secondary side magnetic member to produce attraction force between the magnetic pole and the secondary side magnetic member for thereby moving any of the primary side magnetic flux generator unit and the secondary side magnetic member, the magnetic poles having coils respectively provided therebetween and semihard magnetic member provided over tip ends thereof forming a magnetic flux path among a plurality of the magnetic poles, the semihard magnetic member being magnetized by a magnetic flux produced in the magnetic flux path every time the magnetic flux is produced, the semihard magnetic member producing a magnetic flux directed in the opposite direction to that of a residual magnetic flux formed beteen each of the magnetic poles and a secondary side magnetic member when the primary side magnetic flux generator means stops the generation of the magnetic flux, for thereby cancelling the residual magnetic flux. 
     A driving method of a pulse motor including a primary side magnetic flux generator unit having a plurality of magnetic poles and a plurality of secondary side magnetic members, the primary side magnetic flux generator unit generating a magnetic flux passing through a magnetic flux path formed by at least two of the magnetic poles and the secondary side magnetic member to produce attraction force between the magnetic pole and the secondary side magnetic member for thereby moving any of the primary side magnetic flux generator unit and the secondary side magnetic member, the driving method comprising the steps of providing a semihard magnetic member over tip ends of magnetic poles forming the same magnetic flux path among a plurality of the magnetic poles of the primary side magnetic flux generator means, magnetizing the semihard magnetic member by a magnetic flux produced in the magnetic flux path every time the magnetic flux is produced, and permitting the semihard magnetic member to produce a magnetic flux directed in the opposite direction to that of a residual magnetic flux formed between each of the magnetic poles and a secondary side magnetic member when the primary side magnetic flux generator means stops the generation of the magnetic flux, for thereby cancelling the residual magnetic flux. 
     A driving method of a pulse motor including a stator, a movable member, and a plurality of main coils wound around the stator for relatively moving the stator and the movable member by allowing the main coils to be excited in succession, the driving method comprising the steps of providing auxiliary coils in the vicinity of the respective main coils and exciting the auxiliary coil after the main coils have been excited so as to generate a magnetic flux oppositely to a magnetic flux produced by the main coils.