Okuma Corporation

Nagoya University

Hajimu Ishii

Kiyoshi Yoshino

Kohei Nishimura

Akihide Hamaguchi

Hiroshi Ueno

Eiji Shamoto

Tomoharu Ando

Norikazu Suzuki

Hiroshi Inagaki

In a machine tool which includes a rotary shaft configured to allow a tool or a workpiece to be attached thereto, a driving unit for causing the rotary shaft to rotate is regulated to change a rotation speed of the rotary shaft in such a manner that the rotation speed oscillates with a given amplitude and a given period with respect to a given mean rotation speed, so that chatter vibrations can be suppressed. A parameter display control unit configured to cause a display device to display parameter information related to predetermined parameters for changing at least one of the mean rotation speed, the amplitude and the period is provided so that the parameters can be changed based upon the parameter information displayed in the display device.

Machine tool

When a rotation speed is fluctuated, a fluctuation diagram showing the relationship between a fluctuation amplitude and a fluctuation period of the rotation speed is displayed on a monitor. In addition to a current setting value, a settable range of the fluctuation amplitude and the fluctuation period is displayed on the fluctuation diagram. At least one of an optimal fluctuation period Pbased on Equation (1) below and an optimal range Pof the fluctuation period based on Equation (2) below is also displayed on the fluctuation diagram, wherein T is a rotation period of a rotary shaft, and a, a, aare preset coefficients.&#x2003;&#x2003;(1)&#x2003;&#x2003;(2)

Monitoring method and monitor apparatus for monitoring rotation speed of rotary shaft in machine tool, and machine tool

In suppressing chatter vibration of a rotary shaft in a machine tool by fluctuating rotation speed of the rotary shaft, easy setting of a fluctuation parameter is realized. In a monitor apparatus of the machine tool, a graph showing a fluctuation amplitude of the rotation speed is displayed. On this graph, a current fluctuation position (first point) is indicated by a black circle marker, and also, a power limit line L of a motor fluctuation period is depicted based on a predetermined equation. In an area not exceeding the power limit line L, a new fluctuation position (second point) having a larger fluctuation amplitude and a shorter fluctuation period than the current fluctuation position is calculated and indicated with an arrow A guiding this new point from the current fluctuation position.

Method for monitoring rotary shaft rotation speed fluctuation in machine tool, monitor apparatus, and machine tool

A vibration suppressing device includes a memory unit storing a stable rotation speed calculated by an arithmetical unit in association with a rotation speed range that includes the stable rotation speed, in which, when a command rotation speed that is a rotation speed of a rotary shaft is inputted in starting machining operation by rotation of the rotary shaft and, the arithmetical unit determines whether the command rotation speed is included in the rotation speed range or not, reads out the stable rotation speed when the command rotation speed is included in the rotation speed range and outputs the stable rotation speed to an NC device instead of the command rotation speed, and starts the machining operation at the stable rotation speed.

Growing community of inventors

Niwa-gun, Japan

Hajimu Ishii