JPH02124265A - Cnc grinder equipped with control device for synchronizing position - Google Patents

Abstract

PURPOSE:To constrain the cause disturbing a synchronous control operation by providing a control device for outputting a control signal to a master driving circuit and slave driving circuit and making in an operation state the current limit circuit of the slave driving circuit according to the detection signal transmitted from a detector and to the rotating state of a master servomotor and slave servomotor. CONSTITUTION:A master driving circuit 51 and slave driving circuit 54 feed current to a master servomotor 14 driving a master axis 13 and to a slave servomotor 24 driving a slave axis 19 respectively. A control device 30 also outputs a current limit command actuating the current limit circuit 541 of the slave driving circuit 54, according to a detection signal output by a detector and the rotating state of the master servomotor and slave servomotor by clamping a work W on both axes of master and slave axes, limiting the driving force of the slave servomotor 24 driving the slave axis 19 to the driving force of the master servomotor driving the master axis and making the master servomotor 14 as a main leader.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a CNC grinding machine that grinds a workpiece while fixing it to two work spindles, a master spindle and a slave spindle.

[Prior art]

Conventionally, in CNC grinding machines that have two work spindles, a master axis and a slave axis, for grinding workpieces such as crankshaft crank bins, the driving method for these work spindles is to drive one work spindle. Machining was performed by controlling the drive of the other machining spindle as a synchronous axis using a mechanical connection such as a gear from a servo motor. In this configuration with mechanical coupling of gears, etc., there is a transmission loss in the gear system to the driving force of the servo motor that drives the master shaft, the driving force of the dual shafts is not generated in the same way, and there is backlash in the gear system. Therefore, it was not possible to perform complete synchronous control machining. Furthermore, due to the complexity of the mechanical system, a lot of time is required for maintenance and the like.

[Problem to be solved by the invention]

As an improvement to the method of driving the work spindle described above, a servo motor is connected to each of the two work spindles, a master axis and a slave axis, and the mechanical connection of the two work spindles is separated, and the mechanical system is simplified as a servo synchronous axis. is possible. However, by clamping the workpiece to the workpiece spindle, both servo motors are fixed to each other through the workpiece, which can cause interference between the two servo motors (subtle deviations in the timing of correction operations by the servo system). This causes a slight difference in their movements, and when the driving force of one servo motor is applied to the other servo motor, the two servo motors try to cancel each other's driving forces, resulting in an unstable positioning situation.
(hunting phenomenon), which affects each other's spindle operations. The present invention has been made to solve the above problems, and its purpose is to simplify the mechanical system by coupling servo motors to two work spindles and separating the mechanical coupling, In addition, position synchronization enables synchronous control without causing interference between both servo motors even when the two work spindles, the master axis and slave axis, are fixed together by clamping the workpiece. An object of the present invention is to provide a CNC grinding machine equipped with a control device.

[Means to solve the problem]

The structure of the invention for solving the above problems has two work spindles, a master axis and a slave axis, which pivotally support a workpiece on both end faces and apply rotational force to the workpiece. A CNC grinding machine that synchronously controls the rotational position of axes, wherein a master servo motor that drives the master shaft, a slave servo motor that drives the slave shaft, and a current is supplied to the master servo motor according to a control signal. a master drive circuit that supplies current to the slave servo motor according to a control signal, and a current limit circuit that limits the output current of the slave drive circuit;
a detector that outputs a detection signal by clamping the workpiece to both the master axis and the slave axis; a detector that outputs a control signal to the master drive circuit and the slave drive circuit; and a detection signal from the detector; The present invention is characterized by comprising a control device that outputs a current limiting command to put a current limiting circuit of the slave drive circuit into an operating state in accordance with a signal and a rotational state of the master servo motor and the slave servo motor.

[Effect]

The control device outputs a control signal to a master drive circuit and a slave drive circuit, and the master drive circuit and slave drive circuit supply current to a master servo motor that drives the master axis and a slave servo motor that drives the slave axis, respectively. . Furthermore, the control device adjusts the current of the slave drive circuit according to the detection signal output by the detector by clamping the workpiece to both the master axis and the slave axis and the rotational state of the master servo motor and slave servo motor. Outputs a current limit command that activates the limit circuit. By limiting the driving force of the slave servo motor that drives the slave axis relative to the driving force of the master servo motor that drives the master axis, and making the master servo motor take the initiative.
It is possible to suppress causes that disturb the synchronous control operation.

【Example】

The present invention will be described below based on specific examples. FIG. 1 is a configuration diagram showing the mechanical configuration and electrical configuration of a CNC grinding machine equipped with a position synchronization control device. Reference numeral 10 denotes a bed of a CNC grinding machine, and a table 11 driven by a servo motor 16 via a feed screw 17 is disposed on the bed 10 so as to be slidable in the Z-axis direction parallel to the spindle axis. A headstock 12 on which a master shaft 13 is mounted and a headstock 15 on which a slave shaft 19 is mounted are arranged on the table 11.
9 are rotated by a master servo motor 14 and a slave servo motor 24, respectively. And the master axis 13
A workpiece W consisting of a crankshaft is fixed by a chuck mechanism (path shown) with one slave shaft and one slave shaft. A tool stand 20 that can move forward and backward toward the workpiece W is guided behind the bed 10, and a grinding wheel G that is rotationally driven by a motor 21 is supported on the tool stand 20. This tool stand 20 is connected to a servo motor 23 via a feed screw 22, and is moved forward and backward by forward and reverse rotation of the servo motor 23. The drive units 51 and 54 that constitute the master drive circuit and the slave drive circuit, and the drive units 52 and 53 that drive the servo motors of the other axes receive a speed command, which is a control signal, from the numerical control device 30 that constitutes the control device. , respectively servo motors 14, 24.16.23
This is the circuit that drives the . And master servo motor 1
4. The slave servo motor 24 is equipped with an absolute encoder (A/E) that detects its rotational position as an absolute position.
) 55 and 56 are connected, and their output signals are input to the drive CPU 36 via the interface 38 of the numerical control device 30. In addition, the master servo motor 14 and the slave servo motor 2
4 are connected to speed detectors 57 and 58 for detecting their rotational speeds, and their output signals are input to drive units 51 and 54, respectively. The numerical control device 30 is a device that mainly numerically controls the rotation of the control shaft to control the grinding of the workpiece W and the correction of the grinding wheel G. The numerical control device 30 includes a CPU 31 for controlling the CNC grinder and a ROM that stores a control program.
33 and a RAM 32 for storing input data and the like. A JC data area 321 for storing NC data is formed in the RAM 32. The numerical control device 30 also includes servo motors 14 and 16.
, 23. As the drive system of 24, the drive CPU 36 and R
AM35 is provided. RAh435 is CPU31
This is a storage device into which positioning data of the grinding wheel G, table J1, master shaft 13, and slave shaft 19 are input. The drive CPU 36 sends speed commands calculated from slow-up, slow-down, angle of the master axis and positioning data of the Snob axis relative to the feed of the control axis related to machining to each drive unit at regular intervals.
3.54, and further outputs a current limit command signal that activates the current limit circuit 541 in the drive unit 54. Further, a tape reader 41 for inputting data etc. through an interface 34, a keyboard 42 for inputting data, and a CRT display 43 for displaying data are connected to the CPU 31, and an interface 39 is connected to the CPU 31.
A detector 18 that outputs a workpiece detection signal and an operation panel 45 that outputs signals such as machining start commands are connected through the. Next, its effect will be explained. Figure 2 shows a numerical control device 300C that constitutes the same embodiment device.
It is a flowchart which showed the processing procedure of PU31. According to the example of the NC program shown in FIG.
The flowchart in FIG. 2 will be explained with reference to the time chart in FIG. 4 which explains the timing at which the current limiter outputs the current limiter command to the current limiter circuit 541 of the drive unit 54. First, in step 100, the NC data is stored in the NC data area 321 of R, A, M32, and is shown in FIG.
Decipher the contents of data block N000 in the program. This content is a command to attach the workpiece W to the workpiece spindle, and the process moves to step 102.
It is determined whether the contents of the data book D_tsku decoded in step 1 are an END command. Since it is not an END command, the process moves to step 104 and reads the workpiece detection signal from the detector 18. At this point, the workpiece W is not attached to the workpiece spindle and is not clamped, so the workpiece detection signal is OFF. Next, the process moves to step 10G, in which the clamping states of the master shaft 13 and slave shaft 19 of the workpiece W are determined. Since the detection signal from the detector 18 is OFF, this determination is NO.
Proceeding to step 126, an OFF multiplier signal is input as a current limit command to the current limit circuit 541 of the drive unit 54, and the current limit remains canceled (to in the time chart of FIG. 4). Next, the process moves to step 128, and as processing using the C and NC data, for example, handling by a robot, etc.
Attach the workpiece W to the workpiece spindle. Then, the process returns to step 100 and the contents of data block N001 in the NC program shown in FIG. 3 are decoded. Since this content is a clamp command for the work spindle of the workpiece W, steps 102 to 126 are explained in the same manner as described above, and the process moves to step 128, in which the master axis 13 and slave axis 1 are
The two work spindles 9 clamp the workpiece W. Then, the detection signal from the detector 18 becomes mouth N. Then, the process moves to step 100, and the contents of data block N002 in the NC program shown in FIG. 3 are decoded. Since this content is a movement command for the table 11, steps 102 to 104 will be explained in the same way as the above explanation, and in the judgment of step 106, since the detection signal from the detector 18 is ON, this judgment is YES. Therefore, the process moves to step 108, where it is determined whether or not the driving of the two work spindles, the master spindle 13 and the slave spindle 19, is stopped. At this point, the spindle drive is stopped, so step 1
10, an ON signal is output as a current limit command to the current limit circuit 541 of the drive unit 54 that drives the slave servo motor 24, and the slave servo motor 2
4 starts current limiting (ti in the time chart of FIG. 4. Next, proceed to step 112, and step 1
It is determined whether the contents of the data block decoded with 00 is a spindle drive start command. Since it is not a spindle drive start command, the determination at step 112 is NO, and the process moves to step 118, where it is determined whether the content of the data block decoded at step 100 is a spindle drive stop command. Since it is not a spindle drive stop command, step 118
The determination is NO, and the process moves to step 120 where the NC
As a process based on the data, the table 11 is moved and the workpiece W is moved to the designated position for grinding. and,
Proceeding to step 100, the contents of data block N003 in the NC program shown in FIG. 3 are decoded. Since this content is a spindle drive start command, steps 102 to 110 will be explained in the same way as the above explanation, and in the determination at step 11.2, since it is a spindle drive start command, this determination will be YES, and step 11.
4, the current limiting circuit 54 of the drive unit 54
1, an OFF signal is output as a current limit command to cancel the current limit. Next, the process moves to step 116, and the driving of the two work spindles, the master axis and the slave axis, is started (t2 in the time chart of FIG. 4). Next step 100
Then, the contents of data blocks N004 to N007 in the NC program shown in FIG. 3 are sequentially decoded. In these contents, steps 102 to 106 are explained in the same manner as described above, and step 10
In the determination of step 8, since the main shaft is being driven, the determination is No and the process moves to step 112. Steps 112 to 118 are explained in the same manner as described above, and in step 120, these contents are sequentially executed as processing using NC data, and steps 102 to 120 are repeated. Then, in step 120, the third
When the content of the data block N007 in the NC program shown in the figure has been executed, the process moves to step 100.
Decipher the contents of data block 8. Since this content is a spindle drive stop command, steps 102 to 1 are executed.
12 is explained in the same way as above, and in the judgment of step 118, since it is a command to stop driving the spindle, this judgment becomes YES, and the process moves to step 122, in which the drive of the two work spindles, the master axis and the slave axis, is stopped. Stop. Next, the process moves to step 124, where 0N (i) is output as a current limit command to the current limit circuit 541 of the drive unit 54 that drives the slave servo motor 24, and current limit of the slave servo motor 24 is started (Fig. 4). ts in the time chart).Next, the process moves to step 100 to decode the contents of data block N0O9 in the NC program shown in FIG. 1〕8
is explained similarly to the above explanation, and in step 120 the NC
As data processing, the table 11 is returned. Then, the process moves to step 1.00, and the contents of data block N010 in the NC program shown in FIG. 3 are decoded. Since this content is an unclamp command for the work spindle of the workpiece W, steps 102 to 118 will be explained in the same manner as described above, and step 1
20, the two work spindles, the master axis 13 and the slave axis 19, unclamp the I crop W as a process based on the NC data. Then 7. The detection signal from the detector 18 is turned OFF. Then, the process moves to step 100, and the contents of data block N011 in the NC program shown in FIG. 3 are decoded. Since this content is a 1-2 command to remove one crop W from the work spindle, steps 102 to 104 are explained in the same way as the explanation for -F' and the door, and in the judgment at step 106, the detector 1- Since the detection signal from 8 is OFF, this determination is NO, and step 1
26, outputs the F signal as a current limit command to the drive unit l-54 (7) current limit circuit 541, and cancels the current limit (tl in the time chart in Figure 4).
. Next, in step 128, the workpiece W is removed from the workpiece spindle by handling using, for example, an i-1 pot as processing based on the NC data. Then, the process moves to step 100, and the contents of the data block No. 12 in the NC program shown in FIG. 3 are decoded. Since this content is a program END command, the determination at step 102 is YBS, and the program is completed. In this way, when the workpiece W is fixed to the master shaft 13 and the slave shaft 19, the workpiece detection signal of the detector 18 is ON, and the master servo motor 14 and the slave servo motor 24 are in a stopped state, the drive unit 54 A current limit command signal is output from the numerical control device 30 to limit the drive current of the slave servo motor 24. Therefore, in a stopped state where both servo motors are likely to interfere and become unstable, the driving force of the master servo motor 14 can be made sufficiently larger than the driving force of the slave servo motor 24. Therefore, with the master servo motor 14 taking the initiative, it is possible to reliably stop the motor at the positioning position determined by the master servo motor 14, thereby avoiding an unstable state such as a hunting state. In the above embodiment, when the master servo motor 14 and the slave servo motor 24 are stopped, -) the current limit signal is output when the two work spindles, the master axis 13 and the slave axis 190, are stopped. In addition, the timing of this current limitation is to execute it when the speed control is below a predetermined threshold;
At speeds above which the driving force of both servo motors is required, the current restriction of the slave servo motor 24 may be canceled. Furthermore, the RAM 32 of the numerical control device 30
11 current limit commands and current limit off commands are added as NCC data commands stored in the NC data area 321 of It may be possible. In that case, by creating an appropriate program, more flexible control becomes possible. Note that the function to limit the current described in the above program etc. is generally equipped as part of the servo amplifier function such as the drive unit 54, and does not require special hardware. The addition of this function can be implemented with almost no impact on costs.

【Effect of the invention】

In the present invention, a master 1i (l!) and a 2-piece shaft of a knob shaft 1i (l!) support a workpiece at both end surfaces and apply rotational force to the workpiece.
There is a CNC grinding machine that has two work spindles and synchronously controls the rotational positions of the master and slave axes. , a master drive circuit that supplies current to the master servo motor and the slave servo motor according to a control signal, a current limiting circuit that limits the output current of the slave drive circuit, and a master shaft. A detector that outputs a detection signal by clamping a workpiece to both axes of the slave axis, and a control signal that outputs a control signal to the master drive circuit and slave drive circuit, and the detection signal from the detector and the master servo motor and slave servo motor. The control device outputs a current limit command to activate the current limit circuit of the slave drive circuit according to the rotational state of the slave drive circuit, and the workpiece can be clamped to both the master axis and the slave axis. According to the detection signal output by the detector and the rotational state of the master servo motor and slave servo motor, a current limit command is output from the control device to the slave drive circuit, and the slave servo motor The driving force of the servo motor is limited, and the master servo motor takes the lead, making it possible to suppress the causes of disturbances in synchronous control operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the mechanical and electrical configurations of a CNC grinding machine equipped with a position synchronization control device according to a specific embodiment of the present invention. FIG. 2 shows the CPU 31 of the numerical control device 30 according to the same embodiment.
Flowchart showing the processing procedure. FIG. 3 is an explanatory diagram showing an example of an NC program. FIG. 4 is a time chart showing the timing of current limitation according to the same embodiment. 0 Bed 11 Table 13 ・Master axis 9 Slave axis 14-Master servo motor 4 Slave servo motor 0 Numerical control device 1.52.53.54-Drive unit grinding wheel W-
Patent attorney for workpiece patent Toyoda Machinery Co., Ltd. Representative Patent attorney Shudai Makiya 1゜1゜t.

Claims (1)

[Scope of Claims] The workpiece has two workpiece spindles, a master shaft and a slave shaft, which pivotally support the workpiece on both end surfaces and apply rotational force to the workpiece,
CNC that synchronously controls the rotational position of the master axis and slave axis
The grinding machine includes: a master servo motor that drives the master axis; a slave servo motor that drives the slave axis; a master drive circuit that supplies current to the master servo motor according to a control signal; and the slave servo. a slave drive circuit that supplies current to the motor according to a control signal; a current limiting circuit that limits the output current of the slave drive circuit; and clamping the workpiece to both the master axis and the slave axis. a detector that outputs a detection signal; and a control signal that outputs a control signal to the master drive circuit and the slave drive circuit, depending on the detection signal from the detector and the rotational state of the master servo motor and the slave servo motor, A C equipped with a position synchronization control device, characterized in that it has a control device that outputs a current limit command to put the current limit circuit of the slave drive circuit into an active state.
NC grinding machine.