Linear motor with magnet rail support, end effect cogging reduction, and segmented armature
View Patent ↗A linear motor is provided which includes members for engaging a magnet rail to prevent bending of the magnet rail. Such members may include a wheel or sliding block, for example. The members exert a force proximate an upper edge of the magnet rail to counter potential bending of the magnet rail during operation of the motor, and thereby avoid substantial variations in the air gaps. Furthermore, an armature yoke is provided which includes at least one partial tooth at one end of the armature yoke for reducing an end effect cogging of the linear motor armature in relation to a magnet rail along which the armature will run. In addition, an armature yoke is provided which includes multiple segments which are held end-to-end via fasteners. Such fasteners may serve as part of the magnetic flux path. A support strip may be provided to reduce bowing.
1. A linear motor armature, comprising:
an armature yoke including N teeth separated by slots, where N is an integer, and coil windings within the slots which are energized during operation of the motor; and
wherein the armature yoke further comprises at least one partial tooth at one end of the armature yoke for reducing an end effect cogging of the linear motor armature in relation to a magnet rail along which the armature will run, and does not include any partial teeth at the other end of the armature yoke.
2. The linear motor armature of claim 1 , wherein the armature yoke including the at least one partial tooth is made of a soft magnetic material.
3. The linear motor armature of claim 1 , wherein an end effect cogging force of the at least one partial tooth is approximately 180 degrees out of phase from an end effect cogging force of the armature yoke without the at least one partial tooth.
4. The linear motor armature of claim 1 , wherein the teeth and slots are skewed to reduce slot cogging.
5. The linear motor armature of claim 1 , wherein the armature yoke comprises a plurality of partial teeth at the one end.
6. The linear motor armature of claim 5 , wherein the plurality of partial teeth are spaced apart from one another.
7. A linear motor armature yoke, comprising;
a relatively long yoke having a front face comprising a plurality of slots for receiving armature windings, a rear face and two side faces; and
at least one thin support strip secured to one of the side faces to reduce bowing along the length of the yoke.