Linear synchronous motor
AssigneeSiemens Aktiengesellschaft
InventorsKlaus Greubel, Axel Knauff
Life of this patent
Estimating the term…
Abstract
In order to suppress virtually completely the cyclic power variation of a linear synchronous motor, the latter has the following features. At least one primary part (1) and at least one secondary part (6), which has a sequence of poles (10) formed by permanent magnets, and is also larger than the length of the primary part (1) in the movement direction (5). The primary part (1) has primary slots (9) which are suitable for receiving monophase or polyphase windings. Moreover, the primary part (1) has means for changing the magnetic force in the movement direction (5) of the linear motor in the region of the end piece (2) of the primary part (1). The end faces (14) of the end pieces (2) extend perpendicular to the movement direction (5) of the linear motor.
Claims12
A linear synchronous motor comprising:
- a) at least one primary part (1) and at least one secondary part (6);
- b) the secondary part (6) has a sequence of poles (10) formed by permanent magnets;
- c) the length of the secondary part (6) is greater than the length of the primary part (1) in the movement direction (5),
- d) the primary part (1) has primary part slots (9) which are suitable for holding monophase or polyphase windings,
- e) the primary part (1) has means which lead to a change in the magnetic force in the movement direction (5) of the linear motor in the region of the end pieces (2) of the primary part (1), and
- f) the end faces (14) of the end pieces (2) extend perpendicular to the movement direction (5) of the linear motor,
- wherein the air gap between the end pieces (2) and the part (6) changes gradually within a single pole pitch so as to realize a continuous increase or decrease in the magnetic force in the movement direction (5) of the linear motor in the region of the end pieces (2) of the primary part (1), wherein the geometry of the parts, facing the air gap, of the end pieces (2) is selected in accordance with the following relationship:
- y ( x ) = δ 0 [ 1 1 - x x 0 · [ 1 - ( 1 1 + y 0 δ 0 ) ] - 1 ]
- wherein
- δ0 is the magnetically active air gap between the secondary part and the primary part, including the height of the permanent magnets,
- x0 is the extent of the part of the end piece in the direction of movement of the linear motor having a non-constant air gap,
- y0 is a height of the part of the end piece having a non-constant air gap at x0 and,
- y(x) is the coordinate of the part of the end piece having a non-constant air gap at the point x.
A linear synchronous motor comprising:
- at least one primary part defined by a length and having slots for receiving monophase or polyphase windings, said primary part having end pieces extending perpendicular to a direction of movement of the linear motor;
- at least one secondary part having a series of poles formed by permanent magnets, said secondary part defined by a length which is greater than the length of the primary part in a direction of movement of the linear motor;
- and means, associated to the primary part, for changing the magnetic force in the direction of movement of the linear motor in the region of the end pieces of the primary part,
- wherein an air gap between the end pieces and the secondary part changes gradually within a single pole pitch so as to realize a continuous increase or
- decrease in the magnetic force in the movement direction of the linear motor in the region of the end pieces of the primary part,
- wherein each said end piece has a part adjacent the air gap, said part of the end piece having a geometry selected in accordance with the following relationship:
- y ( x ) = δ 0 [ 1 1 - x x 0 · [ 1 - ( 1 1 + y 0 δ 0 ) ] - 1 ]
- wherein
- δ0 is the magnetically active air gap between the secondary part and the primary part, including a height of the permanent magnets,
- x0 is the extent of the part of the end piece in the direction of movement of the linear motor having a non-constant air gap,
- y0 is a height of the part of the end piece having a non-constant air gap at x0 and,
- y(x) is the coordinate of the part of the end piece having a non-constant air gap at the point x.
Dependencies are inferred from the claim text.