Coil unit and coil assembly for iron-less linear motor

A coil unit comprising:

• an insulation wire bent continuously to form a loop which encloses a hollow portion, the coil unit having two vertical function sides and two axial non-function sides, a bent section formed adjacent to each of the two axial non-function sides so as to alternatively arrange the multiple coil units by inserting the vertical function side of one coil unit into the hollow portion of the adjacent coil unit, the coil unit having two side areas, a width D1 of the vertical function side being defined from the side area corresponding to the vertical function side, a distance between two respective insides of the two vertical function sides being defined as D2, D2=m×D1+ΔL, wherein m represents a number of the vertical function sides of other coil units received in a vertical direction of the hollow portion, ΔL being a width of a gap which receives a separation plate between at least two adjacent vertical function sides.