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US 10,029,340 B2Granted
Machine tool
AssigneeFanuc Corporation
InventorGaku Isobe
Life of this patent
Estimating the term…
Abstract
In a machine tool in which a spindle head is driven by a spindle head drive motor via a ball screw/nut mechanism, tools of different weights are each installed in the spindle head beforehand, a load torque applied to the spindle head drive motor is obtained, and relational data between the tool weight and the load torque is stored. When each tool is installed in the spindle head, the weight of the tool is estimated from, the load torque detected by a load torque detection unit while the spindle head is stopped, and the relational data between the tool weight and load torque.
Claims14
A machine tool, comprising:
- a spindle head to/from which a tool is attachable/detachable;
- a spindle motor configured to rotate the spindle head;
- a spindle head drive motor configured to move the spindle head in a vertical direction;
- a ball screw/nut mechanism coupled between the spindle head and the spindle head drive motor, wherein the spindle head drive motor is configured to move the spindle head in the vertical direction via the ball screw/nut mechanism;
- a load torque detection unit configured to detect a load torque applied to the spindle head drive motor;
- a data storage unit configured to
- obtain beforehand a relationship between a weight of a tool installed in the spindle head and a load torque that is applied to the spindle head drive motor under a predetermined drive condition, with respect to a plurality of objects of different weights, and
- store the relationship as relational data between weights of installed objects and load torques;
- and
- a processor configured to
- detect a load torque of the spindle head drive motor under the predetermined driving condition when the tool is installed in the spindle head using the load torque detection unit, and
- estimate the weight of the tool installed in the spindle head based on the detected load torque and the relational data between weights of installed objects and load torques which are stored in the data storage unit,
- wherein an operation of the spindle head is changed in accordance with the estimated weight of the tool.
10 more elements
A machine tool, comprising:
- a spindle head to/from which a tool is attachable/detachable;
- a spindle motor configured to rotate the spindle head;
- a spindle head drive motor configured to move the spindle head in a vertical direction;
- a ball screw/nut mechanism coupled between the spindle head and the spindle head drive motor, wherein the spindle head drive motor is configured to move the spindle head in the vertical direction via the ball screw/nut mechanism;
- a load torque detection unit configured to detect a load torque applied to the spindle head drive motor;
- and
- a processor configured to, in use of a relational expression between a weight of a tool installed in the spindle head and a load torque applied to the spindle head drive motor under a predetermined driving condition and on the basis of the load torque detected by the load torque detection unit under the predetermined driving condition,
- calculate and estimate the weight of the tool installed in the spindle head,
- wherein an operation of the spindle head is changed in accordance with the estimated weight of the tool.
6 more elements
A machine tool, comprising:
- a spindle head to/from which a tool is attachable/detachable;
- a spindle head drive motor for driving the spindle head;
- a load torque detection unit configured to detect a load torque applied to the spindle head drive motor;
- a data storage unit configured to
- obtain beforehand a relationship between a weight of a tool installed in the spindle head and a load torque that is applied to the spindle head drive motor under a predetermined drive condition, with respect to a plurality of objects of different weights, and
- store the relationship as relational data between weights of installed objects and load torques;
- and
- a processor configured to
- detect a load torque of the spindle head drive motor under the predetermined driving condition when the tool is installed in the spindle head using the load torque detection unit, and
- estimate the weight of the tool installed in the spindle head based on the detected load torque and the relational data between weights of installed objects and load torques which are stored in the data storage unit,
- wherein
- an operation of the spindle head is changed in accordance with the estimated weight of the tool,
- the spindle head is configured to be driven in a vertical direction,
- the machine tool further comprises a ball screw/nut mechanism configured to drive the spindle head, and the processor is further configured to calculate and estimate a tool weight m and the load torque T from the relational expressions below, established between the load torque T and the tool weight m of the spindle head drive motor when the spindle head is driven,
- T=((M+m)gL/2πη+Tp)Z+(J1+Z2(J2+(M+m) (L/2π)2))α
- where
- M represents the weight of the spindle head,
- Z represents a reduction rate of a deceleration mechanism provided between the spindle head drive motor and the ball screw,
- L represents a lead of the ball screw,
- η represents an efficiency of the ball screw,
- TP represents a frictional torque,
- J1 represents an inertia moment of the spindle head drive motor,
- J2 represents an inertia moment of the ball screw, and
- α represents an angular acceleration of a motor shaft of the spindle head drive motor.
21 more elements
Dependencies are inferred from the claim text.