Okuma Corporation

Nagoya University

Akihide Hamaguchi

Hiroshi Ueno

Eiji Shamoto

Tomoharu Ando

Kiyoshi Yoshino

Norikazu Suzuki

Hajimu Ishii

Shunsuke Fujimaki

Hiroshi Inagaki

Kohei Nishimura

A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a variation value setting unit, a drawing unit, a first display unit, and a settable range calculating unit. The settable range calculating unit is configured to calculate a settable range of a variation amplitude and a variation cycle based on a calculation formula. The calculation formula includes the variation cycle, a difference between a first rotation speed and a second rotation speed at mutually different timings among the rotation speeds varied relative to a reference rotation speed, an inertia of a rotating body, a rated output of a motor that drives a main spindle, and a usage proportion to the rated output of the motor.

Monitoring device and monitoring method of main spindle rotating speed in machine tool, and machine tool

A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a drawing unit, a variation position display unit, and a reduction effect index display unit. The drawing unit is configured to display a variation diagram that illustrates a relationship between a variation amplitude and a variation cycle of the rotation speed. The reduction effect index display unit is configured to display a reduction effect index on the variation diagram. The reduction effect index represents a reduction effect of chatter vibration. The reduction effect index is calculated based on a speed ratio that is a ratio of a rotation speed of one rotation before to a rotation speed at an identical rotation position of the main spindle at any given timing.

Monitoring device and monitoring method of main spindle rotation speed in machine tool, and machine tool

The monitoring apparatus includes vibration sensors that detect vibration accompanying machining, a rotation detector and a rotation detection section that detect rotation of a main spindle, and a stability limit and vibration distribution calculation section that creates, on the basis of vibration information obtained from the vibration sensors and a rotation speed of the main spindle detected by the rotation detector and rotation detection section, both a stability limit diagram illustrating a relationship between the rotation speed and a stability limit of the machining and a vibration distribution diagram illustrating a relationship between the rotation speed and the vibration, and displays the created diagrams on a monitor in a vertical arrangement.

Monitoring method and monitoring apparatus for machine tool, and machine tool

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

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.

Vibration suppressing device

A calculating member carries out Fourier analysis of a vibrational acceleration to calculate a maximum acceleration and frequency thereof. The calculating member then compares the maximum acceleration with a threshold value, and when the acceleration exceeds the threshold value, the calculating member calculates a k-value and phase information, and stores each calculated value. When retrying is selected, the calculating member determines a type of a current chatter vibration from the phase information, determines the existence of a chatter vibration which is different from the determined chatter vibration, and calculates each new phase information according to the determined chatter vibration and an existence of a different chatter vibration which had been generated before generation of the current vibration. The calculating member then calculates a k-value from new phase information, calculates the optimum rotation speed by using the k-value, and changes the rotation speed to the optimum rotation speed.

Growing community of inventors

Niwa-gun, Japan

Akihide Hamaguchi