US Patent 7568423 Magnet type rodless cylinder

Repulsive magnetic forces in the axial direction of cylinder tubes act between the rows 11 of inner magnets of pistons 10, 10 accommodated in two cylinder tubes 2, 2, and the inner magnets 12 of the pistons 10 come to a halt being slightly deviated relative to the outer magnets 22 in the axial direction of the tube. Due to this deviation, a magnetic holding force Fc is produced between the inner and outer magnets 12, 22. Since the magnetic holding force Fc is produced in a static state, a smooth movement can be attained from a static state suppressing the occurrence of a stick slip phenomenon at the start of movement as compared to the prior art, which does not produce the magnetic holding force in a static state.