| 摘要 |
PURPOSE:To grasp the condition of welding clearly and perform sure quality control by detecting distortion generated in a pressure transmitting device of the electrode of a resistance welding machine, by comparing it with the set value and controlling welding current. CONSTITUTION:Distortion generated in upper and lower pressure levers of a resistance welding machine is detected by strain gauges 8, 9 and their outputted power is applied to amplifiers 24, 29. Both outputted voltage are applied to a sample hold circuit 34 through an adder 33. This applied voltage is controlled by pulse, and distortion detected by strain gauges 8, 9 is outputted in voltage value by stages. DC power source is applied to the emitter 32 of a transistor 30 and strain gauges 8, 9 are pulse controlled by applying voltage through an erector 33, and inductive voltage is removed. The detected voltage of strain gauges 8, 9 is held at every half cycle, and compared with voltage waveform indicating distortion detected by experiment. When the peak value of detected voltage drops to the set value, welding current is stopped or decreased. |
