A spot welding system 10 includes a spot welding gun having an opposite electrode 44, a movable electrode 48, and a drive part 52, a position detection part 54 that detects a position of the movable electrode 48, and a pressure change calculation part that calculates an amount of change between first pressurizing force at a first attitude and second pressurizing force at a second attitude based on a first position of the movable electrode 48 when the drive part 52 has been driven by a first pressurizing force command at the first attitude, a second position of the movable electrode 48 when the drive part 52 has been driven by the first pressurizing force command at the second attitude, and the first pressurizing force command. The first pressurizing force command and the first pressurizing force coincide with each other.

An apparatus includes a housing, a lever, a plurality of gears and a sensor. The housing may be configured to receive a weld head. The lever may be rotatably attached to the housing and configured to convert a linear position of a free end of the lever relative to the housing into a first angular position of a first shaft relative to the housing. The gears may be configured to transform the first angular position of the first shaft to a second angular position of a second shaft. The sensor may be coupled to the second shaft and configured to generate a value representative of the linear position of the free end of the lever by a measurement of the second angular position of the second shaft.

Provided is a welding gun control device whereby it is possible to reduce a load placed on a workpiece during workpiece detection in spot welding. This welding gun control device for controlling a welding gun for pressing an object to be welded between a movable electrode driven by a servomotor and a counter electrode facing the movable electrode and performing welding comprises: an operation control unit for causing the movable electrode to move at a first speed in a state in which the object to be welded is disposed between the movable electrode and the counter electrode, and causing the counter electrode or the object to be welded to move at a second speed slower than the first speed; and a workpiece detection unit for detecting the object to be welded on the basis of the operating state of the servomotor for driving the movable electrode, while the movable electrode and the counter electrode are caused to move by the operation control unit.

A weld head for spot welding two or more components together. The weld head includes first and second electrode assemblies and a linear actuator motor to drive the first electrode assembly into a desired position and apply a desired clamping force. The weld head also includes a temperature sensor coupled to the linear actuator motor and configured to measure a temperature of the linear actuator motor. The weld head also includes a controller configured to monitor the temperature measured by the temperature sensor and, based upon the temperature, adjust the current supplied to the linear actuator motor to maintain the desired clamping force.

A spot welding apparatus according to is provided that includes an upper and lower moving unit, an upper welding gun, a left and right moving unit and a lower welding gun. In particular, the upper and lower moving unit includes a slide block that is provided at one side of an arm of a robot to move vertically by actuation of an actuator. The upper welding gun is mounted on the slide block and the left and right moving unit is installed at one side of the upper welding gun to horizontally move the upper welding gun by actuation of the actuator. Additionally, the lower welding gun is mounted to correspond to a lower side of the upper welding gun.

A welding gun equipped with a retaining unit, which includes a first retaining member and a second retaining member, and retains a stationary gun arm and a movable gun arm. A retaining hole for retaining the stationary gun arm, guide grooves for insertion of rolling members provided on an aim holder that retains the movable gun arm, connecting member insertion holes into which connecting members connecting the first retaining member and the second retaining member are inserted, and a retained member insertion hole for inserting a retained member retained by a moving member that moves the retaining unit to a welding operation location, are formed in the first retaining member and the second retaining member, and the regions where these components are formed are set as thick-walled regions having a greater thickness than other regions. Thus, adequate rigidity is ensured while avoiding an increase in weight.