METHOD OF CHROMING ROTORS OF SCREW HYDRAULICS Russian patent published in 2017 - IPC C25D17/12 

FIELD: machine engineering.

SUBSTANCE: method involves placing the rotor in a hollow anode, forcing the electrolyte into the space between the surfaces of the coated rotor and the anode, applying a layer of solid chromium at the temperature of 50°C in the electrolyte stream, an anode is used, the inner surface of the anode is made in the form of a helical gear surface, with the end profile of the anode being made in the form of an equidistant of the rotor end profile described by the equations x_a=x_r+H⋅sinν_r, y_a=y_r+H⋅cosν_r, ν_r=ξ_r-δ_r, where x_a, y_a - the coordinates of the anode end profile, x_r, y_r - the coordinates of the rotor end profile, H - the distance along the normal from the rotor tooth end profile to the equidistant, ν_r - the angle between the tangent to the end profile at the current point end of the rotor tooth profile and the axis of ordinates, ξ_r - the angle between the tangent to the end profile at the current point end of the rotor tooth profile and the radius passing through the current point, δ_r - the angle between the radius passing through the current point end of the rotor tooth profile and the axis of ordinates.

EFFECT: creating a chrome coating with the same thickness of chromium over the entire profile of the rotor teeth, increasing the hardness of the coating.

1 tbl, 1 ex, 4 dwg