Process for controlling the rotational speed of a grinding machine, and device therefor

• Main Author: SCHAEDLICH, FRITZ
• Format: Patent
• Language: English; French; German
• Published: 07.08.1985
• Edition: 4
• Subjects: DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS; GRINDING; MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; PERFORMING OPERATIONS; POLISHING; TRANSPORTING

Es wird ein Verfahren vorgeschlagen, mittels dem die Umfangsgeschwindigkeit einer Schleifscheibe einer Schleifmaschine auch bei unterschiedlichen Durchmessern konstant gehalten werden kann. Zu diesem Zwecke wird das Massenträgsheitsmoment der Schleifscheibe beim Anlaufen des Werkzeuges ermittelt und wird zur Bestimmung der Drehzahl verwendet. Geeignete Meßgrößen sind beispielsweise der Anlaufstrom oder die Anlaufdrehzahl und deren Änderung. A signal representative of the mass moment of inertia of a grinding wheel and its drive motor is integrated for a fixed time interval during start-up of the motor beginning when the motor speed or the motor current has reached a predetermined small value, and the integration result is stored until the integrator and storage circuit are reset by a new start-up operation. The integrator result is used to modify a voltage which represents a desired operating speed so as to compensate for differences in value of the mass moment of inertia, making the desired speed smaller when the mass moment of inertia is greater, and vice versa. The result is to hit the desired speed in a manner compensating for the wearing down of the diameter of the grinding wheel, so that the peripheral speed of the grinding wheel is regulated at a substantially constant speed, even though in successive start-ups the grinding wheel diameter diminishes. The integrated signal may be the motor current which varies directly with the mass moment of inertia, or the rotary speed of the shaft which varies inversely with the mass moment of inertia. Sensitivity to changes in diameter is greater when the operating voltage is reduced during start-up and at least until the end of the measuring interval.