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

Patent metadata

Field	Value
Publication number	US-11243221-B2
Application number	US-202017061693-A
Country	US
Kind code	B2
Filing date	Oct 2, 2020
Priority date	Oct 30, 2019
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

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.

First claim

What is claimed is:

1. A monitoring device of a main spindle rotation speed in a machine tool that displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool, the machine tool including a main spindle and the rotation speed variation unit, the main spindle to which a tool or a workpiece is mounted being motor-driven, the rotation speed variation unit continuously varying the rotation speed of the main spindle in any given pattern, the monitoring device comprising:
a variation value setting unit configured to set a variation amplitude and a variation cycle of the rotation speed;
a drawing unit configured to display a variation diagram in the display unit, the variation diagram illustrating a relationship between the variation amplitude and the variation cycle;
a first display unit configured to display a current variation position in the variation diagram; and
a settable range calculating unit configured to calculate a settable range of the variation amplitude and the variation cycle based on a calculation formula, the calculation formula including 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 as a reference for the rotation speed, an inertia of a rotating body including the tool or the workpiece and the main spindle, a rated output of a motor that drives the main spindle, and a usage proportion to the rated output of the motor, wherein
the calculation formula is Math. 1 below,

R
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J

e
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P

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P
C

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S
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R: Variation cycle
S 1 : Rotation speed at any given timing t 1 (first rotation speed)
S 2 : Rotation speed at any given timing t 2 (second rotation speed)
J: Inertia of rotating body
P: Rated output of motor
P c : Sum of cutting output and loss output
e: Usage proportion.

2. The monitoring device of the main spindle rotation speed in the machine tool according to claim 1 , wherein
the calculation formula includes a ratio of the first rotation speed to the second rotation speed.

3. The monitoring device of the main spindle rotation speed in the machine tool according to claim 1 , wherein
any one of the first rotation speed and the second rotation speed is set as a maximum value of the rotation speed and another is set as a minimum value of the rotation speed.

4. The monitoring device of the main spindle rotation speed in the machine tool according to claim 1 , further comprising
an output limit line display unit configured to generate an output limit line of the motor based on the settable range calculated by the settable range calculating unit and display the output limit line on the variation diagram.

5. The monitoring device of the main spindle rotation speed in the machine tool according to claim 1 , wherein
the variation value setting unit is configured to simultaneously set the variation amplitude and the variation cycle based on the calculation formula.

6. A machine tool comprising:
a main spindle to which a tool or a workpiece is mounted is motor-driven;
a rotation speed variation unit configured to continuously vary the rotation speed of the main spindle in any given pattern; and
the monitoring device of the main spindle rotation speed according to claim 1 .

7. The monitoring device of the main spindle rotation speed in the machine tool according to claim 4 , further comprising:
a variation position calculating unit configured to calculate a new variation position where the variation amplitude is larger than the variation amplitude of the current variation position and the variation cycle is shorter than the variation cycle of the current variation position in a range equal to or less than the output limit line, or a new variation position where the variation amplitude is larger than the variation amplitude of the current variation position or the variation cycle is shorter than the variation cycle of the current variation position in a range equal to or less than the output limit line; and
a second display unit configured to display the new variation position in the variation diagram together with a guide display, the guide display guiding a change from the current variation position.

8. The monitoring device of the main spindle rotation speed in the machine tool according to claim 7 , wherein
the new variation position is set to a position on the output limit line where the variation amplitude is same as the variation amplitude of the current variation position.

9. The monitoring device of the main spindle rotation speed in the machine tool according to claim 7 , wherein
the new variation position is set to a position where the variation amplitude becomes a maximum on the output limit line.

10. The monitoring device of a main spindle rotation speed in a machine tool that displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool, the machine tool including a main spindle and the rotation speed variation unit, the main spindle to which a tool or a workpiece is mounted being motor-driven, the rotation speed variation unit continuously varying the rotation speed of the main spindle in any given pattern, the monitoring device comprising:
a variation value setting unit configured to set a variation amplitude and a variation cycle of the rotation speed;
a drawing unit configured to display a variation diagram in the display unit, the variation diagram illustrating a relationship between the variation amplitude and the variation cycle;
a first display unit configured to display a c

Assignees

• Okuma Machinery Works Ltd

Inventors

• Fujimaki Shunsuke
• Hamaguchi Akihide

Classifications

• G01P1/07

  Indicating devices, e.g. for remote indication (indicating working conditions of vehicles G07C5/00) · CPC title

• B23Q17/10 Primary

  for indicating or measuring cutting speed or number of revolutions · CPC title

• B23Q17/0976 Primary

  Detection or control of chatter (B23Q15/12 takes precedence) · CPC title

• G05B19/406

  characterised by monitoring or safety (G05B19/19 takes precedence) · CPC title

• G01P3/02 Primary

  Devices characterised by the use of mechanical means · CPC title