US 4,905,417 AGranted

Numerical control grinding machine

AssigneeToyoda Koki Kabushiki Kaisha

InventorsYukio Oda, Yoshio Wakazono

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Abstract

In a numerical control grinding machine using a grinding wheel made of cubic boron nitride, a computerized numerical controller controls the infeed movement of a wheel head to effect a rough grinding, a drifty grinding and a fine grinding on a rotating cylindrical workpiece. The drifty grinding due to a spring-back motion which is caused by a flexed workpiece is initiated in response to a sizing signal from a sizing device which measures the workpiece diameter varying momentarily during the grinding operation and is terminated upon the expiration of a predetermined time which is sufficient to vanish the variation of the workpiece diameter. A sizing device measures the actual diameter thereafter, and the sizing signal is compensated in order to approximate the actual diameter to a desired set size which is the sum of a finish diameter and a predetermined allowance for the subsequent fine grinding operation, as the number of the workpieces increases. That is, the numerical controller diminishes a set size which determines the time point to issue the sizing signal from the sizing device, toward the desired set size on a step-by-step basis with the increase in number of the workpieces ground.

Claims3

Dependent claims

A grinding machine wherein a sizing device is provided for outputting a sizing signal when a cylindrical workpiece is ground to a set size, and wherein in response to said sizing signal from said sizing device, the infeed movement of a wheel head rotatably carrying a grinding wheel is halted in a rough grinding operation prior to a fine grinding operation, the improvement comprising:

size setting means for storing a workpiece diameter upon which said sizing signal is to be issued;
infeed halt means for halting the infeed movement of said wheel head upon the issuance of the sizing signal;
diameter read command means for outputting a diameter read command to said sizing device in order to cause said sizing device to measure the actual diameter of said workpiece when a grinding caused by a spring-back motion of said workpiece ends after the halt of said infeed movement;
reference value storing means for storing a reference value which indicates a diameter size of said workpiece having a desired allowance on account of said subsequent fine grinding operation;
difference value calculation means for calculating a difference between said reference value and said actual workpiece diameter measured in response to said diameter read command;
and
sizing compensation means for compensating said workpiece diameter stored in said size setting means for said difference calculated by said difference value calculation means.

4 more elements

Dependencies are inferred from the claim text.