Linear motor with reduced cogging

Claim 2

A linear driving device utilizing linear motors, which comprises: a set of two linear motors each linear motor including a stator field member having a plurality of permanent magnets and a yoke, and a movable member having polyphase windings and a magnetic pole iron plate and disposed to confront said stator field member in a plane, thereby to relatively displace said movable member with respect to said stator field member through polyphase exciting of said polyphase windings; a rigid structure member connecting, the two movable members in the two linear motors disposed in the direction of displacement, said two movable members being disposed in a parallel relation to each other; and relative positions of the magnetic poles in one of said stator field members of one motor being offset from magnetic poles in the stator field member of the second motor.

Claim 3

A linear driving device utilizing linear motors, which comprises: a set of two linear motors each including a stator field member having a plurality of permanent magnets and a yoke, and a movable member having polyphase windings and a magnetic pole iron plate and disposed to confront said stator field member in a plane, thereby to relatively displace said movable member with respect to said stator field member through polyphase exciting of said polyphase windings; a rigid structure member connecting, the two movable members in the two linear motors disposed in the direction of displacement, said two movable members being disposed in a parallel relation to each other, with relative positions of the magnetic poles in said two stator field members corresponding to said two movable members being arranged to be identical; and a magnetic pole iron plate in a movable member on one of said motors being offset from a magnetic pole iron plate in said movable member of a second motor.

Claim 4

A linear driving device utilizing linear motors, which comprises: a set of two linear motors each including a stator field member having a plurality of permanent magnets and a yoke, and a movable member having polyphase windings and a magnetic pole iron plate and disposed to confront said stator field member in a plane, thereby to relatively displace said movable member with respect to said stator field member through polyphase exciting of said polyphase windings; a rigid structure member connecting, the two movable members in the two linear motors disposed in the direction of displacement, said two movable members being disposed in a parallel relation to each other, with relative positions of the magnetic poles in said two stator field members corresponding to said two movable members being arranged to be identical; and a magnetic pole iron plate in a movable member on one of said motors being offset from a magnetic pole iron plate in said movable member of a second motor.

Claim 5

The apparatus of claim 1, wherein said poles are offset by a value of P/2 wherein P is a pole pitch.

Claim 6

The apparatus of claim 3, wherein said linear direction represents a forward and backward direction of a displacement of said linear motor.

Claim 7

The apparatus of claim 2, wherein said iron plates are offset from each other by a value of P/2 wherein P is a pole pitch.

Claim 8

The apparatus of claim 5, wherein said linear direction represents a forward and backward direction of a displacement of said linear motor.

Claim 9

A linear driving apparatus comprising: two linear motors located substantially parallel to each other; each of said motors including a stator field member having a plurality of permanent magnets and a movable member having windings, a magnetic pole iron plate in operative relationship to said stator field member functioning to relatively displace said movable member with respect to said stator field member through polyphase exciting of said windings; a rigid structure member connecting each movable member which are spaced in parallel relation to each other in the two linear motors; each of said movable members providing cogging of opposite phases; means for substantially cancelling the cogging forces, wherein said movable member of each motor includes a leading and trailing edge, the leading and trailing edge of the movable member of each motor in alignment with each other respectively.

Claim 10

A linear driving apparatus comprising: two linear motors located substantially parallel to each other; each of said motors including a stator field member having a plurality of permanent magnets and a movable member having windings, a magnetic pole iron plate in operative relationship to said stator field member functioning to relatively displace said movable member with respect to said stator field member through polyphase exciting of said windings; a rigid structure member connecting each movable member which are spaced in parallel relation to each other in the two linear motors; each of said movable members providing cogging of opposite phases; means for substantially cancelling the cogging forces, wherein said movable member of each motor includes a leading and trailing edge, the leading and trailing edge of the movable member of each motor in alignment with each other respectively.

Claim 11

A linear driving apparatus comprising: two linear motors located substantially parallel to each other; each of said motors including a stator field member having a plurality of permanent magnets and a movable member having windings, a magnetic pole iron plate in operative relationship to said stator field member functioning to relatively displace said movable member with respect to said stator field member through polyphase exciting of said windings; a rigid structure member connecting each movable member which are spaced in parallel relation to each other in the two linear motors; each of said movable members providing cogging of opposite phases; means for substantially canceling the cogging forces, wherein the magnets of each of said motors has side edges adjacent to side edges of another magnet, and the side edges of the magnets of one motor being in alignment with the side edges of the magnets of the other motor.

Claim 12

A linear driving apparatus comprising: two linear motors located substantially parallel to each other; each of said motors including a stator field member having a plurality of permanent magnets and a movable member having windings, a magnetic pole iron plate in operative relationship to said stator field member functioning to relatively displace said movable member with respect to said stator field member through polyphase exciting of said windings; a rigid structure member connecting each movable member which are spaced in parallel relation to each other in the two linear motors; each of said movable members providing cogging of opposite phases; means for substantially canceling the cogging forces, wherein the magnets of each of said motors has side edges adjacent to side edges of another magnet, and the side edges of the magnets of one motor being in alignment with the side edges of the magnets of the other motor.

Claim 13

The apparatus of claim 7 wherein the magnets of each of said motors has side edges adjacent to the side edges of another magnet and said means includes at least the side edges of at least on of said plurality of magnets of each of said motors being offset from each other.

Claim 14

The apparatus of claim 8 wherein the movable member of each of said motors having leading and trailing edges and said means includes the leading and trailing edges of said movable members being offset from each other.