A High Precision Servomechanism of a Constant Speed for NC Machines

这台数控机床对大批量生产很有用。特别地，它适合于生产复杂的机器元件。然而，数控机床不适合制造齿轮等特殊部件。例如，直到几年前，还无法通过数控切割或数控磨削工艺获得高精度齿轮。这是因为数控齿轮加工需要高精度的同步伺服系统。本研究课题的负责人江村在大约10年前开发了一种非常高精度的伺服机构，他试图将其伺服机构应用于NC型齿轮切削机床。然后，他成功地用数控滚齿机切削了高精度齿轮。这项研究工作是为了通过直接驱动技术提高切削或磨削速度而进行的。由于直驱伺服机构的等效转动惯量很小，为了减小伺服主轴的旋转振动，采用了惯性阻尼器，并充分提高了伺服机构的位置环增益。此外，作者还采用了T.他们的高速伺服主轴。经过实验，他们成功地以4,000 rpm的速度旋转主轴，精度达到20“pp。这些速度和精度对于数控滚齿机和数控磨齿机来说是足够高的。

The NC machine is useful for mass production. In particular, it is suitable for producing a complex machine element. However, the NC machine is not suitable for making a special component such as gears. For example, until several years ago, it had been unable to get high precision gears by NC cutting or NC grinding process. It is because a high precisely synchronized servomechanisms are required for NC gear process.T. Emura of the head of this research project developed a very high precision servomechanism about ten years ago, and he tried to apply his servomechanism to gear cutting machines of NC type. Then he succeeded in cutting high precision gears by a NC hobber.This research work is carried out in order to increase cutting or grinding speed by means of a direct-drive technique. Since the equivalent moment of inertia of the direct-drive servomechanism is extremely small, an inertial damper was used and the position loop-gain of the servomechanism was increased sufficiently in order to decrease the rotary vibration of a servo- spindle. Moreover the authors applied a new PLL developed by T. Emura to their high speed servo-spindle. After experiments, they succeeded in rotating their spindle at a speed of 4,000rpm and with the accuracy of 20"pp. These speed and accuracy are high enough for NC gear hobbers and NC gear grinders.