Dengensha Manufacturing Company Limited

Keiji Kameta

Yoshio Sato

Junichi Taniguchi

A motor-driven resistance spot welding machine includes: a drive rod having an electrode tip on an end thereof and making a linear motion; a linear guide for guiding the linear motion of the drive rod, the linear guide including a bearing; and a reduction gear being supported by a gun arm or a gun bracket. The machine also linearly drives the drive rod in an electrode force direction by transmitting an output torque of an electric motor to the reduction gear. In the machine, a rear portion of the drive rod is connected to a swing lever through a link, the swing lever being secured either to an output shaft of the reduction gear or to a main body of the reduction gear, whereby an arcuate motion is transmitted to the swing lever by an output of the electric motor, and is then converted into a linear motion of the drive rod by the link to thereby drive the drive rod so as to apply electrode force. As a result of this construction, the reduction gear is sealed, so that the reduction gear is free from welding splashes. Such problems as the large moment of inertia (GD.sup.2) and the restricted strokes of the ball-bearing leadscrew and the nut can be overcome. Further, gun parts are grouped by function. That is, the functions are unitized into a drive unit for generating electrode force, and a welding unit including the electrode tips, the gun arm, the welding transformer, and the like, so that parts are unitized into common parts so as to be standardized. Further, a new bracket which can be used irrespective of the posture of the gun attached to the robot can be realized.

Motor-driven resistance spot welding machine

A motor-driven X-type resistance spot welding gun. A servo-controlled motor torque is converted into force to drive gun arms and into electrode force by using a reduction gear without converting rotational output of the motor into rectilinear motion. The two arms are respectively attached to an output shaft of the reduction gear or a case, and the rotational output of the motor can be converted into swing-wise movement to close and open the arms. The electrode tips on the arms nip a workpiece to apply electrode force to the workpiece, and current is passed through the workpiece to perform spot welding. A motor, a reduction gear and the like are assembled on a common base to form a driving unit so that an arm actuator for the X-type resistance spot welding gun is formed. The same driving unit can be used commonly to various X-type gun models. The independent properties of functions of a bracket for attaching the welding gun to a robot are improved. Since properties of the arm actuator and the bracket are not dependent on a welding unit of the gun (portion through which welding current flows), the production cost for a manufacturer and maintenance cost for a user are reduced.

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Kanagawa, Japan

Keiji Kameta