METHOD AND APPARATUS FOR DETERMINING THE VOLTAGE AT THE ELECTRODES OF A SPOT WELDING GUN
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Abstract
A method and an apparatus for determining the temporal curve of the voltage (ue(t)) at the electrodes (3) of a spot welding gun (1) during a spot welding process as an indicator of the welding quality, wherein the electrodes (3) are fastened to gun arms (2) that can be moved relative to each other are provided. The apparatus includes a device (9) for measuring a measuring voltage (um(t)) between the electrodes (3), that measuring device (9) being connected to measuring leads (6) extending along the gun arms (2), and further includes a compensating coil (7) for measuring a compensating voltage (uk(t)) for compensating measuring errors within measuring leads. In order to determine the temporal curve of the voltage (ue(t)) at the electrodes (3) of the spot welding gun (1) during a spot welding process as precisely as possible, the device (9) for measuring the measuring voltage (um(t)) and the device (10) for measuring the compensating voltage (uk(t)) are designed as separate units for separate detection and are connected to a device (11) for processing the detected values.
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Citations
28 Claims
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1-16. -16. (canceled)
- 17. Method for determining the temporal curve of the voltage (ue(t)) at the electrodes (3) of a spot welding gun (1) during a spot welding process as an indicator for the welding quality, wherein the electrodes (3) are fastened to gun arms (2) that can be moved relative to each other, wherein a measuring voltage (um(t)) is measured via measuring leads (6) and an induced compensating voltage (uk(t)) is measured using a compensating coil (7), wherein the measuring voltage (um(t)) and the compensating voltage (uk(t)) are detected separately and the relation (v(t)) between measuring voltage (um(t)) and compensating voltage (uk(t)) is determined at those times, when erratic voltage changes occur, and the compensating voltage (uk(t)) is multiplied by the determined relation (v(t)) and subtracted from the measuring voltage (um(t)) to determine the electrode voltage (ue(t)).
- 24. Apparatus for determining the temporal curve of the voltage (ue(t)) at the electrodes (3) of a spot welding gun (1) during a spot welding process as an indicator for the welding quality, wherein the electrodes (3) are fastened to gun arms (2) that can be moved relative to each other, comprising a device (9) for measuring a measuring voltage (um(t)) between the electrodes (3), said measuring device (9) being connected to measuring leads (6) extending along the gun arms (2), and further comprising a compensating coil (7) for measuring a compensating voltage (uk(t)) for compensating measuring errors in the measuring leads (6), wherein the device (9) for measuring the measuring voltage (um(t)) and the device (10) for measuring the compensating voltage (uk(t)) are designed as separate units for separate detection and connected to a device (11) for processing the detected values, said processing device (11) being designed for detecting the measuring voltage (um(t)) and the compensating voltage (uk(t)) and for determining a relation (v(t)) between the measuring voltage (um(t)) and the compensating voltage (uk(t)) at those times, when erratic voltage changes occur, and for multiplication of compensating voltage (uk(t)) by the determined relation (v)t)) and subtraction of the compensating voltage (uk(t)) multiplied by relation (v(t)) from the measuring voltage (um(t)) to determine the electrode voltage (ue(t)).
Specification