JPH03213245A - Control device for machine tool - Google Patents

Abstract

PURPOSE:To reduce cost of a control device for a machine tool by driving a spindle motor at a preset speed simultaneously inputting its preset value to a shaft feed speed arithmetic part and calculating a shaft feed speed from an each rotational feed preset value and a spindle rotational speed preset value. CONSTITUTION:A spindle motor 12 is driven at a preset rotational speed by outputting a spindle rotational speed command, set from a spindle rotational speed setting part 21, to a spindle driving gear 22 of the spindle motor 12. Simultaneously, a preset value of the spindle rotational speed setting part 21 is input to a shaft feed speed arithmetic part 26, and a shaft feed speed of a shaft feed device 14 is calculated, by the shaft feed speed arithmetic part 26 from an each rotational feed preset value, which is an output of an each rotational feed setting part 25, and from the preset value of the spindle rotational speed setting part 21, and commanded to a shaft feed driving gear 27 of a feed motor 15. Accordingly, a spindle rotational speed in the point of time, a spindle rotational speed preset value is fetched to the shaft feed speed arithmetic part 26, is prevented from generating a difference from the spindle rotational speed preset value commanded to the spindle driving gear 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for main shaft rotation and blade feed of a machine tool.

[Prior Art] Conventionally, when automatic machining is performed using a machine tool, for example, as shown in FIG. 12
A set rotation speed is commanded to the main shaft drive device 22, which is constituted by an inverter or the like. The main shaft motor 12 is provided with a pulse generator 13 that detects the amount of rotation, and generates pulses corresponding to the amount of rotation (rotation angle or number of rotations) of the main shaft, and the pulses are counted by a counter 23. The value of the counter 23 is read at regular intervals, and based on this value, the spindle rotation speed calculation unit 24 calculates the spindle rotation speed and feeds it back to the spindle drive device 22.

On the other hand, the shaft feeder 1 of the cutter per rotation of the main shaft 11
Set the axis feed amount of 4 (hereinafter referred to as the transfer amount each time) in the transfer setting section 25 every time, and set the axis feed speed to 7 m -ys.
#t li ; 1 The shaft feed speed of the shaft feed device 14 is calculated from the main shaft rotation speed calculated by the central shaft rotation speed calculated by the staff 24, and the shaft feed speed of the feed motor 15 is driven. Device 2
7.

[Problems to be Solved by the Invention] However, in the above configuration, the spindle rotation speed is calculated by counting the pulses of the pulse generator 13 at a constant period, so if there is a fluctuation in the spindle rotation speed, the calculation process may be slow. Even if the control device calculates the shaft feed speed, the spindle rotation speed at the time when the spindle rotation speed is taken into the shaft feed speed calculation section 26 via the counter 23 and the spindle rotation speed calculation section 24 is not transmitted to the spindle drive device 22. An error may occur between the commanded spindle rotation speed setting value. As a result, the shaft feed speed changes, and in the case of thread cutting, the pitch of the thread changes.

Furthermore, the pulse generator 13 that detects the amount of rotation of the main shaft motor 12 may be used, such as sensorless vector control in which the main shaft motor 12 is an induction motor and the main shaft drive device 22 is frequency-controlled from the vector of the secondary interlinkage magnetic flux of the induction motor. Otherwise, the control device would be complicated, such as requiring a separate rotation amount detection circuit to calculate the shaft feed speed.

An object of the present invention is to calculate the shaft feed speed of a shaft feed device with a simple configuration without using a detector for detecting the rotation speed of a spindle motor.

[Means for Solving the Problems] The present invention provides a spindle drive device that drives a spindle motor of a machine tool, a shaft feed drive device that drives a feed motor of a shaft feed device of the machine tool, and a spindle drive device that drives a feed motor of a shaft feed device of the machine tool. a spindle rotation speed setting section for setting the spindle rotation speed; a transfer setting section for setting the amount of transfer each time of the shaft feed device per revolution of the spindle rotation speed; In a control device for a machine tool, which is provided with an axis feed rate calculation unit that calculates, an every-time transfer setting value sent from the every-time transfer setting unit and a spindle rotation speed setting value sent from the spindle rotation speed setting unit. is input to the shaft feed speed calculation section, and the calculation result by the shaft feed speed calculation section is input as a command value for the shaft feed drive device.

[Operation] A spindle rotation speed command is sent to the spindle drive device from the spindle rotation setting section, and at the same time the spindle motor is driven at the set rotation speed,
Input the setting value of the spindle rotation setting section to the axis feed speed calculation section,
The speed calculation section calculates the shaft feed speed of the feed device from the every-time transfer setting value that is the output of the every-time transfer setting section and the setting value of the spindle rotation setting section, and instructs the shaft feeding drive device.

Therefore, no error occurs between the spindle rotation speed at the time when the spindle rotation speed setting value is taken into the shaft feed speed calculating section and the spindle rotation speed setting value commanded to the spindle drive device.

[Example] The present invention will be described with reference to embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which a spindle rotation speed setting section 21 sets the rotation speed of the spindle 11 of the machine tool 1.
is provided in the control device 2 to command a set rotation speed to the main shaft drive device 22 using an inverter or the like of the main shaft motor 12. In addition, the control device 2 includes an every-time transfer setting section 25 that sets the every-time transfer amount of the blade axis feed device 14 per rotation of the main shaft 11, and an every-time transfer setting section 25 that is the output of the every-time transfer setting section 25. A shaft feed speed calculation section 26 is provided to calculate the shaft feed speed of the shaft feed device 14 from the set value and the set value of the main shaft rotation setting section 21, and the shaft feed speed is commanded to the shaft feed drive device 27 of the feed motor 15. That's what I do.

With the above configuration, the spindle rotation speed command set from the spindle rotation speed setting section 21 is commanded to the spindle drive device 22 of the spindle motor 12 to drive the spindle motor 12 at the set rotation speed, and at the same time, the spindle rotation speed setting section 21 The set value is input to the shaft feed speed calculation section 26, and the shaft feed speed calculation section 26 calculates the setting value of the shaft feed device 14 from the every time transfer setting value which is the output of the every time transfer setting section 25 and the setting value of the spindle rotation setting section 21. The shaft feed speed is calculated and commanded to the shaft feed drive device 27 of the feed motor 15.

Therefore, there is no difference between the spindle rotation speed at the time when the spindle rotation speed setting value is taken into the shaft feed speed calculation section 26 and the spindle rotation speed setting value commanded to the spindle drive device 22.

[Effects of the Invention] As described above, according to the present invention, even if there is no detector for detecting the rotation speed of the spindle motor, the spindle rotation speed can be directly input into the shaft feed speed calculation section with a simple configuration. Since it is possible to accurately calculate the feed rate and drive the axis feed device without causing errors due to delays in calculations, etc., it has a great effect on reducing the cost of the control device of the machine tool.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. DESCRIPTION OF SYMBOLS 1... Machine tool, 11... Spindle, 12... Spindle motor, 14... Axis feed device, 2... Control device, 21
...Spindle rotation speed setting section, 22...Spindle drive device, 2
5... Every time transfer setting unit, 26... Axis feed speed calculation unit, 27... Axis feed drive device

Claims (1)

[Claims] 1. A spindle drive device that drives a spindle motor of a machine tool;
a shaft feed drive device that drives a feed motor of the shaft feed device of the machine tool; a spindle rotation speed setting unit that sets the spindle rotation speed of the spindle drive device; In a control device for a machine tool, comprising a transfer setting section for setting a transfer amount each time, and an axis feed speed calculation section for calculating an axis feed speed of the shaft feed drive device,
inputting the every-time transfer setting value sent from the every-time transfer setting section and the spindle rotation speed setting value sent from the spindle rotation speed setting section into the shaft feed speed calculation section; A control device for a machine tool, characterized in that a calculation result obtained by is inputted as a command value for an axis feed drive device.