Numerical control apparatus and machining method

Patent metadata

Field	Value
Publication number	US-10877456-B2
Application number	US-201816349297-A
Country	US
Kind code	B2
Filing date	Mar 5, 2018
Priority date	Mar 5, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A numerical control apparatus includes: a thread-whirling motor controller controlling, based on a thread lead representing a movement amount of a thread whirling tool per rotation of a workpiece, a reference differential speed representing a difference between a predetermined reference rotational speed of the thread whirling tool and a rotational speed of the workpiece, the number of tool blades of the thread whirling tool, and a workpiece spindle speed representing the rotational speed of the workpiece, a first motor moving the thread whirling tool, a second motor rotating the thread whirling tool, and a third motor rotating the workpiece. The thread-whirling motor controller controls: the first motor based on the thread lead and the reference differential speed; the second motor based on the thread lead, the reference differential speed, the number of tool blades, and the workpiece spindle speed; and the third motor based on the workpiece spindle speed.

First claim

The invention claimed is:

1. A numerical control apparatus comprising:
thread-whirling motor control circuitry configured to control, on a basis of a thread lead representing a movement amount of a thread whirling tool per rotation of a workpiece, a reference differential speed representing a difference between a predetermined reference rotational speed of the thread whirling tool and a rotational speed of the workpiece, a number of tool blades representing a number of blades of the thread whirling tool, and a workpiece spindle speed representing the rotational speed of the workpiece, a motor that moves the thread whirling tool, a motor that rotates the thread whirling tool, and a motor that rotates the workpiece,
wherein the thread-whirling motor control circuitry:
calculates movement speed of the thread whirling tool on a basis of the thread lead and the reference differential speed and controls the motor that moves the thread whirling tool such that the thread whirling tool moves at the calculated movement speed;
calculates rotational speed of a spindle of the thread whirling tool on a basis of the thread lead, the reference differential speed, the number of tool blades, and the workpiece spindle speed and controls the motor that rotates the thread whirling tool such that the thread whirling tool rotates at the calculated rotational speed; and
controls the motor that rotates the workpiece on a basis of the workpiece spindle speed.

2. The numerical control apparatus according to claim 1 , further comprising:
thread-cutting command analyzing circuitry configured to analyze a thread cutting command to acquire the thread lead;
differential-speed threading command analyzing circuitry configured to analyze a differential-speed threading command to acquire the reference differential speed and the number of tool blades; and
workpiece-spindle speed command analyzing circuitry configured to analyze a workpiece-spindle speed command to acquire the workpiece spindle speed.

3. The numerical control apparatus according to claim 2 , further comprising:
movement command analyzing circuitry configured to analyze a movement command including a position command value representing a position of a turning tool; and
turning motor control circuitry to control a motor that moves the turning tool on a basis of the position command value.

4. The numerical control apparatus according to claim 3 , wherein:
the thread-whirling motor control circuitry calculates a movement amount of the thread whirling tool per unit time on a basis of the thread lead and the reference differential speed, controls the motor that moves the thread whirling tool on a basis of the calculated movement amount, calculates a rotational speed of the thread whirling tool on a basis of the calculated movement amount, the thread lead, the number of tool blades, and the workpiece spindle speed, controls the motor that rotates the thread whirling tool on a basis of the calculated rotational speed, and controls the motor that rotates the workpiece on a basis of the workpiece spindle speed.

5. The numerical control apparatus according to claim 2 , wherein:
the thread-whirling motor control circuitry calculates a movement amount of the thread whirling tool per unit time on a basis of the thread lead and the reference differential speed, controls the motor that moves the thread whirling tool on a basis of the calculated movement amount, calculates a rotational speed of the thread whirling tool on a basis of the calculated movement amount, the thread lead, the number of tool blades, and the workpiece spindle speed, controls the motor that rotates the thread whirling tool on a basis of the calculated rotational speed, and controls the motor that rotates the workpiece on a basis of the workpiece spindle speed.

6. The numerical control apparatus according to claim 1 , further comprising:
thread-cutting command analyzing circuitry configured to analyze a thread cutting command to acquire the thread lead;
differential-speed threading command analyzing circuitry configured to analyze a differential-speed threading command to acquire the number of tool blades and the reference rotational speed of the thread whirling tool; and
workpiece-spindle speed command analyzing circuitry to analyze a workpiece-spindle speed command to acquire the workpiece spindle speed,
wherein the thread-whirling motor control circuitry calculates the reference differential speed on a basis of the number of tool blades, the reference rotational speed of the thread whirling tool, and the workpiece spindle speed.

7. The numerical control apparatus according to claim 6 , further comprising:
movement command analyzing circuitry to analyze a movement command including a position command value representing a position of a turning tool; and
turning motor control circuitry to control a motor that moves the turning tool on a basis of the position command value.

8. The numerical control apparatus according to claim 7 , wherein:
the thread-whirling motor control circuitry calculates a movement amount of the thread whirling tool per unit time on a basis of the thread lead and the reference differential speed, controls the motor that moves the thread whirling tool on a basis of the calculated movement amount, calculates a rotational speed of the thread whirling tool on a basis of the calculated movement amount, the thread lead, the number of tool blades, and the workpiece spindle speed, controls the motor that rotates the thread whirling tool on a basis of the calculated rotational speed, and controls the motor that rotates the workpiece on a basis of the workpiece spindle speed.

9. The numerical control apparatus according to claim 6 , wherein:
the thread-whirling motor control circuitry calculates a movement amount of the thread whirling tool per unit time on a basis of the thread lead and the reference differential speed, controls the motor that moves the thread whirling tool on a basis of the calculated movement amount, calculates a rotational speed of the thread whirling tool on a basis of the calculated movement amount, the thread lead, the number of tool blades, and the workpiece spindle speed, controls the motor that rotates the thread whirling tool on a basis of the calculated rotational speed, and controls the motor that rotates the workpiece on a basis of the workpiece spindle speed.

10. The numerical control apparatus according to claim 1 , further comprising:
movement command analyzing circuitry to analyze a movement command including a position command value representing a position of a turning tool; and
turning motor control circuitry to control a motor that moves the turning tool on a basis of the position command value.

11. The numerical control apparatus according to claim 10 , wherein:
the thread-whirling motor control circuitry calculates a movement amount of the thread whirling tool per unit time on a basis of the thread lead and the reference differential speed, controls the motor that moves the thread whirling tool on a basis of the calculated movement amount, calculates a rotational speed of the thread whirling tool on a basis of the calculated movement amount, the thread lead, the number of tool blades, and the workpiece spindle speed, controls the motor that rotates the thread whirling tool on a basis of the calculated rotational speed, and controls the motor that rotates the workpiece on a basis of the workpiece spindle speed.

12. The numerical control apparatus according to claim 1 , wherein:
the thread-whirling motor control circuitry calculates a movement amount of the thread whirling tool per unit time on a basis of the thread

Assignees

• Mitsubishi Electric Corp

Inventors

• Kumazawa Tsuyoshi
• Nakajima Kazuya

Classifications

• G05B19/186 Primary

  Generation of screw- or gearlike surfaces · CPC title

• A61B17/1682

  for the foot or ankle · CPC title

• G05B19/232

  with speed feedback only · CPC title

• G05B2219/45215

  Thread cutting · CPC title

• B23G2240/60

  Thread whirling, i.e. production of a thread by means of an annular tool rotating about an axis not coincident with the axis of the thread being produced · CPC title