Patent ID: 8212181
Filing Date: 2012-07-03
Classification: B23K

Abstract:
1. A welding gun driving device comprising: an electric motor; a feed screw mechanism; and a pressure rod axially moved forward and backward via the feed screw mechanism by the electric motor, wherein a turning of the pressure rod is prevented, wherein a rotor of the electric motor is formed into a hollow shape through which the pressure rod is insertable, wherein the feed screw mechanism comprises: a screw shaft fixed to the rotor concentrically with the rotor; and a nut portion screwed to the screw shaft, wherein the pressure rod comprises: the nut portion; and a hollow rod portion extending toward an axial front from the nut portion, and wherein the rotor is provided, at its inner peripheral face, with a guide portion through which the pressure rod is inserted and supported so as to be relatively rotatable and axially slidable.