Toyoda Koki Kabushiki Kaisha

Hayashi Kodama

Ikuo Suzuki

Tamaki Tomita

Ryuji Wada

Kazuo Moriya

Mineo Ishikawa

A grinding machine wherein a CBN grinding wheel is rotatably carried to grind a workpiece on a work support device and is provided with a re-truing device, in addition to a truing and dressing device rotatably carrying a truing roll and a counter roll. When a truing and dressing instruction is generated, the CBN wheel is first trued with the truing roll, is then dressed by free abrasive grain supplied between itself and the counter roll and is finally re-trued with a diamond impregnated truing bar carried on the re-truing device. A re-truing infeed of the truing bar against the CBN wheel is considerably less than a truing infeed of the CBN wheel against the truing roll, and therefore the re-truing is effected on cutting edges of the wheel abrasive grain damaged by the free abrasive grain in dressing, whereby the cutting edges are made somewhat dull.

Grinding machine with a re-truing device

A grinding machine provided with an apparatus for changing a feed rate of a grinding wheel relative to a workpiece just before the grinding wheel comes into contact with the workpiece. An electrode device is mounted adjacent to the grinding wheel and connected to an electric power source for applying a potential to the surface of the grinding wheel. A detecting device detects a difference of potential between the grinding wheel and the workpiece to generate an output voltage. A memory device memorizes the output voltage detected when the grinding wheel is distant from the workpiece. A setting device reduces the memorized output voltage at a predetermined rate to provide a reference voltage corresponding to a predetermined gap between the grinding wheel and the workpiece. A comparator circuit compares the output voltage with the reference voltage to generate a feed rate changing signal when the output voltage attains the reference voltage. A control device controls a feed device so as to change the feed rate of a wheel slide in accordance with the feed rate changing signal.

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Kariya, Japan

Hayashi Kodama