Rotary pulse motor

In a rotary pulse motor comprising:

• (A) a first cylindrical magnetic-path forming means made of magnetic material;
• (B) a second cylindrical magnetic-path forming means made of magnetic material and inserted concentrically into said first cylindrical magnetic-path forming means, said first cylindrical magnetic-path forming means or said second cylindrical magnetic-path forming means being rotatably supported;
• (C) slit-like grooves formed at a regular angular pitch P/2 in a peripheral portion of one of said first and second cylindrical magnetic-path forming means;
• (D) teeth formed between said slit-like grooves;
• (E) permanent magnets inserted into said slit-like grooves and so arranged that the magnetic polarities of said teeth are alternately inverted;
• (F) magnetic-pole means formed at a regular angular pitch of a constant multiplier of said P/2, in the other of said first and second cylindrical magnetic-path forming means, said magnetic-pole means facing to said teeth at a constant air gap in the radial direction, and
• (G) coil means provided on the other of said first and second cylindrical magnetic-path forming means so as to generate magnetic flux through said air gap, the improvement comprising:
• the other of said first and second cylindrical magnetic-path forming means comprises plural cylindrical core portions magnetically combined with each other and arranged in the axial direction of said first and second cylindrical magnetic-path forming means, and said magnetic-pole means comprises plural rows of magnetic poles formed on the respective core portions of the other of said first and second cylindrical magnetic-path forming means, said magnetic poles of the respective rows being angularly shifted from one another by a pitch of a predetermined multiplier of said P;
• whereby a magnetic flux flows through a path passing in succession through--an N-polarized magnetic pole of one of said rows--said air gap--an adjacent S-polarized one of said teeth of said one of the first and second cylindrical magnetic-path forming means--an axial path in said one of the first and second cylindrical path forming means along said permanent magnet--an N-polarized one of said teeth adjacent to said adjacent S-polarized one---said air gap--an S-polarized magnetic pole of another of said rows, adjacent to said N-polarized magnetic pole of the one of said rows--another axial path in said other of the first and second cylindrical magnetic path forming means--and returning to the original N-polarized magnetic pole to complete the path, when said coil means is energized.