JP2009245007A - Device and method for controlling machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a deterioration in machining accuracy and to prevent a main shaft and a tool from interfering with a workpiece by suppressing heat generation of a vertical shaft driving source when stopping the driving of a machine tool and performing control for energy saving. <P>SOLUTION: A control device 20 performing control for energy saving of the machine tool holds the main shaft by a reference point moving means 23, at an original point being a reference point position within an effective range preset in three axial directions of an X-axis, Y-axis and Z-axis when the machine tool stops, and holds the main shaft at a position where the main shaft does not interfere with the workpiece in an X-axial or Z-axial direction. After a timer 24 measures a set time to start an energy saving mode, a Y-axis driving source stopping means 21y interrupts electricity supply to a Y-axis servo motor My and operates a brake device 13. A position monitoring means 25 detects a positional deviation amount of the main shaft in a Y-axial direction, and a discriminating means 31 discriminates whether the detected positional deviation amount from the reference point position of the main shaft is within an effective range. When the positional deviation amount is outside the effective range, a releasing means 32 releases the energy saving mode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a machine tool control apparatus and method for performing energy-saving control of a drive source when machining is stopped for a long time in a machine tool.

Conventionally, a workpiece is continuously cut by unattended operation in a machining center of a machine tool, for example. For example, when there is no work material at night or when there is no monitoring personnel, this is detected and the spindle for gripping the cutting tool is set to the origin position in the X-axis, Y-axis, and Z-axis directions or to a predetermined standby position. Move to keep the machine stationary for a long time.
At this time, the X-axis and Z-axis drive servomotors can be stopped. However, in the Y-axis direction, which is the vertical axis, it is necessary to maintain its own position against gravity in order to keep the main axis at the origin position or the standby position. A current always flows through the Y-axis driving motor and is kept in a driving state. For this reason, the Y-axis drive motor generates heat, and the heat is transmitted to the machine tool main body, so that the accuracy of the machine tool is lowered and the machining accuracy of the workpiece is deteriorated.

As means for improving such problems, for example, inventions described in the following Patent Documents 1 and 2 are disclosed.
For example, in the invention described in Patent Document 1, it is determined whether or not the control device that controls the punch press machine is in automatic operation, and as hydraulic drive means for supplying pressure oil to the hydraulic cylinder when it is not in automatic operation. The drive of the press motor is stopped. As a result, noise reduction and energy savings by press motors can be achieved when not in automatic operation.
Further, in the servo mechanism control device described in Patent Document 2, the power supply to the servo motor provided in the movable part that moves the controlled object to the predetermined position is stopped at the time of stop, and the brake device of the movable part is operated. The movable part is stopped at a predetermined position. When power supply to the servo motor is stopped, the actual amount of movement in the movable part is detected and input by the position detection sensor, and an abnormal signal is output when the actual amount of movement of the movable part is outside the preset allowable range Like to do.
JP 2000-153318 A Japanese Patent Laid-Open No. 4-15807

However, since the energy-saving device of the punch press machine described in Patent Document 1 performs the energy-saving control by stopping the power drive means when it is not in automatic operation, it is energy-saving when the raw material runs out in the case of unmanned operation or the like. There is a problem that cannot be controlled.
Further, in the servo mechanism control device described in Patent Document 2, when this is applied to a machine tool, when the movable part moves when power supply to the servo motor is stopped, the main shaft is held by the movement of the main shaft. There was a problem that the tool and the workpiece fixed to the table might interfere with each other.

  The present invention has been made in view of such circumstances, and when the drive of the machine tool is stopped, energy saving control is performed and heat generation of the vertical axis drive source is suppressed to prevent deterioration of machining accuracy. It is an object of the present invention to provide a control device and method for a machine tool.

The machine tool control apparatus according to the present invention processes a workpiece by relatively moving a spindle for gripping a tool in three axial directions of an X axis, a Y axis, and a Z axis perpendicular to the workpiece, and a driving source for the spindle. In a machine tool control device that controls energy saving by shutting off the power to the machine, when the machine tool is stopped, the reference point position within the effective range set in advance in the three axis directions of the X, Y, and Z axes And the reference point moving means is a reference point moving means that is in a position where it does not interfere with the workpiece in at least one of the X and Z axis directions, and when the main shaft is moved to the reference point position, the main axis is moved to the vertical axis. The Y-axis drive source stop means for cutting off the energization to the Y-axis drive source that controls the movement in the Y-axis direction that is the direction and operating the brake device, and the energization to the Y-axis drive source and the brake device being operated State The position monitoring means for detecting the positional deviation amount of the main shaft in the Y-axis direction, the determining means for determining whether or not the detected positional deviation amount of the main spindle is within the effective range, and the positional deviation amount of the main spindle are out of the effective range. And a release means for canceling the energy saving mode.
According to the present invention, when the machine tool is stopped, the drive source of the spindle is also stopped, and the spindle is moved relative to the reference point position within the effective range according to this, and the spindle is moved relative to the workpiece at the reference point position. It is arranged at a position that does not interfere with the workpiece in at least one of the X-axis direction and the Z-axis direction. After that, the Y-axis drive source is turned off by the Y-axis drive source stop means to activate braking of the brake device. Then, the position monitoring unit detects the amount of positional deviation of the main shaft in the Y-axis direction to determine whether the positional deviation amount is included in the effective range, and if it is included in the effective range, the energization stop state is maintained. When the energy-saving mode is maintained and the effective range is not satisfied, the energy-saving mode is canceled and the Y-axis drive source is energized and restarted, assuming that the positional deviation from the reference point position of the spindle in the Y-axis direction is large. Moreover, even if the main shaft is lowered in the Y-axis direction in the energy saving mode, there is no possibility of interference with the workpiece because the position of the main shaft is displaced in the X-axis and / or Z-axis direction.

Further, a timer for measuring that a predetermined time has elapsed after the stop of the Y-axis drive source is further provided, and the discriminating means discriminates whether or not the amount of displacement of the main shaft is within the effective range after the predetermined time has elapsed. It is preferable to do so.
After the elapse of a predetermined time measured by the timer after stopping the power supply of the Y-axis drive source and braking by the brake device, the position shift amount of the main shaft in the Y-axis direction is detected by the position monitoring means, and the position shift amount is within the effective range. By determining whether or not it is included, it is possible to detect the amount of positional deviation in the Y-axis direction of the main shaft due to deterioration of the brake device or lowering due to the weight of the main shaft and tool. Here, when the Y-axis drive source is connected to a gear, a backlash abnormality with the gear can also be detected.

Further, automatic control confirmation means for confirming that the machine tool is in the automatic control state may be provided, and the drive source stop means may be operated after confirming that the machine tool is in the automatic control mode.
It can be applied to unattended operation and night operation of machine tools. Further, in the manual control state, since the spindle may be moved, it is not preferable to automatically shift to the energy saving mode.

Further, in the position monitoring means, the amount of positional deviation of the main shaft at the start of the energy saving mode of the Y-axis drive source, and the main shaft at the stage where the energization to the Y-axis drive source is cut off by the drive source stop means and the brake device is activated. An abnormality display means may be provided for calculating a difference from the positional deviation amount and displaying an abnormality when the difference exceeds a preset allowable range smaller than the effective range.
When braking of the brake device is started when power supply to the Y-axis drive source is stopped, a positional shift in the Y-axis direction occurs. This positional shift amount is detected as a difference from the amount of positional deviation of the main shaft when the energy saving mode starts. The abnormality of the brake device can be detected depending on whether or not the set allowable error is exceeded.

In addition, when the main shaft is moved to the reference point position, an X-axis drive source stop unit that cuts off the power to the X-axis drive source that controls movement of the main shaft in the X-axis direction, and a Z-axis that controls movement in the Z-axis direction. Z-axis drive source stop means for interrupting energization to the drive source may be provided.
As a result, the power supply stop can be controlled simultaneously for the three-axis drive source.

A machine tool control method according to the present invention processes a workpiece by moving a spindle holding a tool in three axial directions, ie, an X axis, a Y axis, and a Z axis, which are orthogonal to the workpiece, and a driving source for the spindle. In the control method of a machine tool that performs energy saving control by cutting off the power to the machine, when the machine tool is stopped, the reference point position within the effective range set in advance in the three axis directions of the X axis, Y axis, and Z axis And the spindle at the reference point position is in a position where it does not interfere with the workpiece in at least one of the X-axis and Z-axis directions, and the spindle is moved to the reference point position in the vertical axis direction. The step of shutting off the energization to the Y-axis drive source that is controlled to move in the Y-axis direction and operating the brake device, and the step of turning off the energization to the Y-axis drive source and operating the brake device Axial direction The process of detecting the amount of misalignment and whether or not the detected misalignment of the main spindle is within the effective range, and the energy saving mode is canceled when the misalignment of the main spindle is outside the effective range. It is characterized by.
According to the present invention, even if the main shaft is lowered in the Y-axis direction in the energy saving mode, there is no possibility of interference with the workpiece because the position of the main shaft is displaced in the X-axis and / or Z-axis direction.

Further, a step of measuring that a predetermined time set in advance after the stop of the Y-axis drive source may be measured, and it may be determined whether or not the amount of positional deviation of the spindle is within an effective range after the predetermined time has elapsed.
The reference point position is preferably the origin position in the X-axis, Y-axis, and Z-axis directions.

  According to the spindle energy-saving control device and method according to the present invention, it is possible to perform energy-saving control of a machine tool by shutting off the energization of the Y-axis drive source, and to suppress the heat generation from the Y-axis drive source to deteriorate the machining accuracy. Can be prevented. Moreover, even if the main shaft is lowered in the Y-axis direction in the energy saving mode, there is no possibility of interference with the workpiece because the position of the main shaft is displaced in the X-axis and / or Z-axis direction.

Hereinafter, a control device and a control method for a machine tool according to an embodiment of the present invention will be described with reference to FIGS.
The machine tool 1 shown in FIGS. 1 and 2 is a machining center. A gate-shaped column 3 is erected at one end of a base 2, and a holding portion 4 is provided at a position facing the column 3 on the base 2. Yes. Here, in the machine tool 1, the vertical axis is the Y axis, the horizontal direction in the horizontal plane orthogonal to the Y axis is the X axis, and the vertical direction orthogonal to the X axis is the Z axis.
In the column 3, a pair of X-axis guide rails 6a and 6b are arranged in parallel in a direction orthogonal to the Y-axis direction, and the saddle is movable in the left-right direction (X-axis direction) along the X-axis guide rails 6a and 6b. 7 is disposed. The saddle 7 is provided with a pair of Y-axis guide rails 8a and 8b in the Y-axis direction, and a spindle head 9 that can be moved up and down (Y-axis direction) along the Y-axis guide rails 8a and 8b. Is provided. A main shaft 10 that holds a tool (not shown) projects from the main shaft head 9 in the Z-axis direction.

A ball screw 12 is erected on the saddle 7 in parallel with the Y-axis guide rails 8a and 8b. A Y-axis servo motor My is connected to one end of the ball screw 12 as a Y-axis drive source. A brake device 13 is attached to the Y-axis servo motor My (see FIG. 3). The ball screw 12 is held in a screwed state with the saddle 7 so that the saddle 7 can be moved up and down integrally with the main shaft 10 by forward and reverse rotation driving of the Y-axis servomotor My.
The saddle 7 is provided with a ball screw 14 in parallel with the X-axis guide rails 6a and 6b, and an X-axis servo motor Mx is connected to one end of the ball screw 14 as an X-axis drive source. The ball screw 14 is held in a screwed state with the saddle 7, and the saddle 7 can be moved integrally with the main shaft 10 in the X-axis direction by forward and reverse rotation driving of the X-axis servomotor Mx.

The holding table 4 is provided with a pair of Z-axis guide rails 16a and 16b in a direction orthogonal to the X-axis direction. An APC (auto pallet changer) 17 is attached to the base 2 via a holding table 4, and the two pallets 18 a and 18 a supported on the upper part of the table 18 by the pivotable APC 17 can be exchanged. The table 18 is supposed to be movable in the front-rear direction (Z-axis direction) along the Z-axis guide rails 16a and 16b. A workpiece (not shown), which is a workpiece, is fixed to the pallet 18a at the machining position, and is subjected to cutting with a tool held on the spindle 10.
The pallet 18a at the machining position is connected to a Z-axis servo motor Mz as a Z-axis drive source via a ball screw 19, and the table 18 is moved to the Z-axis guide rail by rotating the Z-axis servo motor Mz forward and backward. It can be moved back and forth in the Z-axis direction along 16a and 16b.
The X-axis servo motor Mx and the Z-axis servo motor Mz are not provided with a brake device because the shaft is not affected by gravity, but the brake devices 27 and 29 are attached as shown by a one-dot chain line in FIG. Also good.

In FIG. 3, a control device 20 that performs energy saving control of each motor in the machine tool 1 is provided. The control device 20 controls the ON / OFF of the Y-axis servo motor My, the X-axis servo motor Mx, and the Z-axis servo motor Mz together with the spindle motor and the B-axis motor (not shown), so that the table 18 and the tool for supporting the workpiece are provided. Control means 22 for controlling the cutting of the workpiece by driving and controlling the gripping spindle 10 is provided.
In the control means 22, the Y axis servo motor My, the X axis servo motor Mx, and the Z axis servo motor Mz are turned off together with the above-described main spindle motor and B axis motor, and a signal that detects the timing when the driving of the machine tool 1 is stopped is detected. Based on this, the reference point moving means 23 drives the motors My, Mx, Mz so as to move the spindle 10 to the reference point position S shown in FIG. 7 for energy saving control.

The reference point position S shown in FIG. 7 is preferably, for example, the position of the origin coordinate O of the X axis, the Y axis, and the Z axis or the vicinity thereof. A position shifted from the held workpiece, that is, a position where the tool does not interfere with the workpiece even when the spindle 10 is lowered by gravity is set. Alternatively, in the Z-axis direction, the tool is set at a position where the tool does not interfere with the workpiece even if the spindle 10 is lowered by gravity. The reference point position S may be a position where the tool held on the spindle 10 is shifted so as not to interfere in at least one of the X-axis direction and the Z-axis direction.
Note that the origin O in the Y-axis direction in the plane of the XY axis is an intersection of the X axis and the Y axis in the XY axis coordinate plane shown in FIG. On the column 3 of the machine tool 1 shown in FIG. 1, the origin O is set at a position close to the X-axis guide rail 6a of the Y-axis guide rails 8a and 8b, for example, a position about 1 mm below the X-axis guide rail 6a. .

For the reference point position S, an effective range L that can be maintained in the energy saving mode state is set. In the Y-axis direction, the effective range L is such that the Y-axis servo motor My is stopped and maintained in a power supply stopped state, and the Y-axis servo motor My is stopped by the brake device 13. 12 is a numerical value range that allows a drop in the Y-axis direction based on the weight of the motor, the braking force that deteriorates with time of the brake device 13, and the like. Further, the X-axis and Z-axis directions are in a numerical range in which movement of the main shaft 10 in the stopped state in the X-axis and Z-axis directions is allowable (see FIG. 7). The effective range L includes the origin O.
This effective range L is set empirically based on the motor weight and the appropriate braking force of the brake device 13 described above. When the Y-axis servo motor My is connected to the ball screw 12 via a gear, it also includes an appropriate backlash distance. In FIG. 7, the effective range L is shown in the XY axis coordinate plane. As shown in FIG. 7, the spindle 10 is moved to a predetermined reference point position S within the effective range L, for example, the origin O by the reference point moving means 23.

Further, the stop time of each motor of the machine tool 1 is measured by the timer 24 based on the signal that detects the timing when the drive of the machine tool 1 is stopped by the control means 22. The timer 24 starts the energy saving mode when a predetermined time t that is set in advance, for example, t = 0 to 30 minutes, cuts off the power supply to the Y-axis servomotor My and activates the brake device 13.
However, if the energy saving mode is started at t = 0 minutes, the brake device 13 is applied to the Y-axis servo motor My and the power supply to each motor is cut off. The start of driving is slightly delayed due to the start control of the motor, which is not preferable. It is preferable to start the energy-saving mode with at least the predetermined time t as a time when several minutes or more have elapsed.
The timer 24 stops the power supply to the Y-axis servomotor My and the Y-axis drive source stop means 21y that outputs the operation signal of the brake device 13 after the predetermined time t has elapsed or at an appropriate stage, and stops the power supply to the motors Mx and Mz. X-axis drive source stop means 21x and Z-axis drive source stop means 21z that individually output the operation signals are provided. In addition, when the brake devices 27 and 29 are provided in the X-axis servo motor Mx and the Z-axis servo motor Mz, the operation signals of the brake devices are output simultaneously.
Further, the Y-axis servo motor My is provided with a position monitoring means 25 for detecting the position of the main shaft 10 in the Y-axis direction. The Y-axis servo motor My always has the main shaft 10 regardless of whether the Y-axis servo motor My is stopped or driven. The position in the Y-axis direction is detected and fed back to the control means 22.
Similarly, the position monitoring means 28 is also installed in the X-axis servomotor Mx, and the position monitoring means 30 is also installed in the Z-axis servomotor Mz.

Further, the control means 22 is provided with a determination means 31, a release means 32, and an automatic control confirmation means 33.
The discriminating means 31 discriminates whether or not the position of the main shaft 10 detected by the position monitoring means 25, 28, 30 in each axial direction is within the effective range L. The discriminating means 31 compares and discriminates the lowering position of the spindle 10 detected by the position monitoring means 25 when the energy saving mode is controlled in the Y-axis direction and when the power supply to the Y-axis servomotor My is cut off in the energy saving mode control state. Is also performed (see FIG. 7). The amount of deviation in the Y-axis direction from the reference point position S is D.
The canceling unit 32 cancels the energy saving mode based on the determination by the determining unit 31. The automatic control confirmation unit 33 determines an automatic control mode and a manual control mode of the machine tool.
Further, an abnormality display means 34 for performing an abnormality display by a signal from the control means 22 is provided. In the abnormality display means 34, the amount of deviation D in the Y-axis direction of the spindle 10 between the start of the energy saving mode in the Y-axis direction, the interruption of power supply to the Y-axis servo motor My, and the operation of the brake device 13 deviates from the preset allowable range. In this case, an abnormality display of the brake device 13 is performed.

The control device 20 of the machine tool 1 according to the present embodiment has the above-described configuration. Next, an energy saving control method will be described based on the flowcharts shown in FIGS.
First, when the cutting of the workpiece by the machine tool 1 is completed, the operation is stopped. When the driving stop of each motor is detected by the control means 22, the reference point moving means 23 moves the spindle 10 to a preset reference point S within the effective range L in the X axis, Z axis, and Y axis directions, for example, the origin O. (See FIG. 5; Step 99). At this time, the main shaft motor, B-axis motor, X-axis servo motor Mx, Z-axis servo motor Mz, and Y-axis servo motor My are stopped.
However, at least the Y-axis servomotor My maintains the energized state in order to maintain the reference point position S, which is the stop position in the Y-axis direction, on the main shaft 10 against gravity. Since the X-axis servo motor Mx and the Z-axis servo motor Mz do not move even when the energization is interrupted, the energization is interrupted here. Or you may hold | maintain in an energized state.

When the control unit 22 detects that the operation of all the motors (main shaft motor, B axis motor, X axis servo motor Mx, Z axis servo motor Mz, Y axis servo motor My) is stopped, the stop time is measured by the timer 24. Is started (step 100). It is determined by the timer 24 whether or not the predetermined state t set in advance has elapsed in the stop state of the spindle 10 (step 101). When the predetermined time t has elapsed, the timer 24 detects this and starts the energy saving mode (step 102). If any of the motors starts to drive before the predetermined time t elapses, the Y-axis energy saving mode is not entered (step 101).
Next, the control means 22 determines whether the control mode of the machine tool 1 is the automatic control mode or the manual control mode. If the control mode is the manual control mode, the energy saving mode is not entered (step 103). This is because in the manual control mode, it is assumed that the operator operates operations such as workpiece feed, workpiece fast feed, and return to origin by the manual pulse generator.
Then, the discriminator 31 confirms that the X axis, Y axis, and Z axis direction positions of the main shaft 10 are within the effective range L. If the effective range L is deviated in any axial direction, the energy saving mode is terminated (step 104).

Next, the energy saving mode is started for the Y-axis servo motor My (step 105), the brake device 13 brakes the Y-axis servo motor My and cuts off the power supply (steps 106 and 107). At the same time, the X-axis servo motor Mx and the Z-axis servo motor Mz are also cut off when they are energized. If the timer 24 has stopped energizing the motors Mx and Mz at the start of measurement, the process proceeds to the next process. When the motors Mx and Mz are provided with brake devices 27 and 29, the brake devices 27 and 29 perform braking.
Simultaneously with the start of the energy saving mode of the Y-axis servo motor My, the coordinate value in the Y-axis direction of the spindle 10 (referred to as the first coordinate value) is detected and stored by the position monitoring means 25 (step 108). Then, the position monitoring means 25 detects and stores the coordinate value in the Y-axis direction of the main shaft 10 immediately after the supply of power to the Y-axis servomotor My is stopped (step 109).
Next, the control means 22 calculates the difference between the first coordinate value and the second coordinate value as a deviation amount D in the Y-axis direction of the spindle 10 (step 110), and whether or not the deviation amount D is within a preset allowable range. Is discriminated by the discriminating means 31 (step 111). When the deviation amount D exceeds the allowable range as the normal deviation amount by the brake device 13, it is determined that the brake device 13 is abnormal, and the abnormality display means 34 displays an abnormality (step 112).

  Thereafter, the coordinate value (referred to as the third coordinate value) in the Y-axis direction of the spindle 10 is detected again by the position monitoring means 25 (step 113), and the third coordinate value is stored by the control means 22 (step 114). The difference from one coordinate value is calculated as the amount of deviation of the main shaft 10 in the Y-axis direction (step 115). Then, it is determined whether or not the coordinate value of the position of the main spindle 10 is within the effective range L even if the amount of deviation in the Y-axis direction is added (step 116). If it is within the effective range L, the brake device 13 is not deteriorated, and the spindle 10 and the tool are able to suppress the descent due to its weight, and it is recognized that they are in the normal energy saving mode. The third coordinate value in the Y-axis direction is detected again.

Here, if it is determined in step 116 that the amount of deviation in the Y-axis direction is out of the effective range L, the deterioration of the brake device 13 progresses, and the Y-axis over time due to the weight of the spindle 10 and the tool. It is determined that the direction descent has progressed, and the energy saving mode of the Y-axis servomotor My is terminated (step 117). Then, power supply to the Y-axis servo motor My, the X-axis servo motor Mx, the Z-axis servo motor Mz, the main shaft servo motor, and the B-axis servo motor is started and the operation of the brake device 13 is turned off (steps 118 and 119). .
Then, the energy saving mode is ended (step 120), the cooler for the main shaft 10 is restarted, and the supply of the lubricant is resumed.

If the amount of descent from the reference point position S of the main shaft 10 when the energization of the Y-axis servo motor My is stopped in the energy saving mode is large, the main shaft 10 may interfere with the work in relation to the work installation position. However, in the present embodiment, the reference point position S of the spindle 10 set by the reference point moving means 23, that is, the origin O, is set to be shifted in at least one direction of the X axis direction and the Z axis direction with respect to the workpiece. Even if it is lowered in the Y-axis direction, that is, in the vertical direction, it does not interfere with the workpiece.
In step 112, when the deviation D between the spindle 10 at the reference point position S and the lowering position of the spindle 10 due to the abnormality of the brake device 13 due to the start of the energy saving mode is out of the allowable range, an abnormality is displayed. . In this case, the machine tool 1 may be stopped and maintenance of the brake device 13 of the Y-axis servomotor My may be performed. Alternatively, the energy saving mode may be continued only by warning with an abnormality display, and maintenance work may be performed when the spindle 10 is out of the effective range L.

As described above, according to the energy saving mode control device 20 of the main spindle 10 in the machine tool 1 according to the present embodiment, the heat generation from the motor My is reduced particularly in order to cut off the energization of the Y-axis servo motor My at the start of the energy saving mode. As a result, it is possible to suppress degradation of machining accuracy based on heat conduction. In addition, since the power supply to each of the motors My, Mx, and Mz is stopped in the energy saving mode, the energy saving effect can be exhibited.
Further, in the energy saving mode, when setting the reference point position S within the effective range L of the spindle 10, the spindle 10 is set at a position shifted from the workpiece in at least one of the X axis direction and the Z axis direction. Even if the servo motor My is de-energized and braked by the brake device 13, the spindle 10 and the tool and the spindle head 9 have their own weight, the brake device 13 is deteriorated, and the like in the Y-axis direction. 10 and the interference between the tool and the workpiece can be prevented.
Furthermore, the degree of deterioration of the brake device 13 can be detected by calculating the amount of deviation D in the Y-axis direction of the main shaft 10 at the start of the energy saving mode and immediately after the supply of power to the Y-axis servo motor My is stopped and the brake device 13 is activated. When a gear is interposed between the Y-axis servo motor My and the ball screw 12, an abnormality due to gear backlash can be detected.

As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to the said embodiment. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.
For example, in the energy saving mode control method according to the above-described embodiment, the first coordinate value of the main shaft 10 at the start of the energy saving mode, the second coordinate value of the main shaft 10 immediately after the Y-axis servomotor My is de-energized and the brake device 13 is activated, By calculating the deviation amount D based on the difference between the two, it is possible to detect the deterioration (or the backlash abnormality) of the brake device 13, but the deviation amount detection control at this point may be omitted. Alternatively, the position monitoring unit 25 may detect the deviation D immediately after the timer 24 is omitted and the spindle 10 is positioned at the reference point position S.

Further, when the control of the energy saving mode is started, the machining of the workpiece by the machine tool 1 is finished and the operation is stopped, and the spindle 10 is set in advance within the effective range L in the X axis, Y axis, and Z axis directions by the reference point moving means 23. The power supply may be cut off at the same time as the main shaft motor, the B-axis motor, the X-axis servo motor Mx, and the Z-axis servo motor Mz are stopped when moved to the reference point S.
In this case, in the energy saving mode control stage, the main shaft 10 does not move in the X-axis direction and the Z-axis direction, which are two axes in the horizontal plane, and does not move, so the Y-axis direction (vertical axis direction) of the Y-axis servomotor My. The effect of the above-described embodiment can be exhibited by detecting only the descending amount to ().

It is a perspective view which shows the principal part of the machine tool by embodiment of this invention. It is a sectional side view of the machine tool shown in FIG. It is a block diagram of the energy-saving mode control apparatus used for a machine tool. It is a 1st flowchart which shows the energy-saving mode control method. FIG. 5 is a second flowchart following the first flowchart of FIG. 4. It is a 3rd flowchart following the 2nd flowchart of FIG. It is a figure which shows the effective range in an XY-axis coordinate, an origin, and the reference point position of a spindle.

Explanation of symbols

1 Machine tool
10 Spindle
18 Table 13, 27, 29 Brake device 18 Table 20 Control device 21y Y-axis drive source stop means 22 Control means 23 Reference point moving means 24 Timers 25, 28, 30 Position monitoring means 34 Abnormal display means My Y-axis servo motor Mx X Axis servo motor Mz Z-axis servo motor L Effective range S Spindle reference point O Origin

Claims (9)

Energy saving is achieved by machining the workpiece by moving the spindle that grips the tool relative to the workpiece in the three directions of the X, Y, and Z axes perpendicular to each other and cutting off the power to the drive source of the spindle. In the control device of the machine tool to be controlled,
When the machine tool is stopped, the main shaft is held at a reference point position within a preset effective range in the three axis directions of the X axis, the Y axis, and the Z axis, and the main shaft at the reference point position is the X axis and the Z axis. A reference point moving means at a position that does not interfere with the workpiece in at least one of the axial directions;
Y-axis drive source stop means for shutting off the energization to the Y-axis drive source for controlling the movement of the spindle in the Y-axis direction which is the vertical axis direction and operating the brake device when the spindle is moved to the reference point position When,
Position monitoring means for detecting the amount of displacement of the main shaft in the Y-axis direction while shutting off the power to the Y-axis drive source and operating the brake device;
A discriminating means for discriminating whether or not the detected positional deviation amount of the spindle is within the effective range;
A control device for a machine tool, comprising: release means for releasing an energy saving mode when the amount of positional deviation of the spindle is out of an effective range. A timer for measuring that a predetermined time has elapsed after the Y-axis drive source is stopped;
The machine tool control device according to claim 1, wherein the discriminating unit discriminates whether or not a displacement amount of the spindle is within an effective range after the predetermined time has elapsed.   3. An automatic control confirmation means for confirming that the machine tool is in an automatic control state is provided, and confirms that the machine tool is in an automatic control mode to operate the Y-axis drive source stop means. The machine tool control device described in 1. In the position monitoring unit, when the energy saving mode of the Y-axis drive source starts, the amount of displacement of the main shaft and when the drive source stop unit cuts off the power to the Y-axis drive source and operates the brake device. The difference with the amount of positional deviation of the spindle is calculated,
4. The machine tool control device according to claim 1, further comprising an abnormality display means for displaying an abnormality when the difference exceeds a preset allowable range smaller than the effective range.   An X-axis drive source stopping means for cutting off the energization to the X-axis drive source for controlling the movement of the main shaft in the X-axis direction when the main shaft is moved to the reference point position, and a Z-axis for controlling the movement in the Z-axis direction The machine tool control device according to any one of claims 1 to 4, further comprising Z-axis drive source stop means for interrupting energization to the drive source.   The machine tool control device according to claim 1, wherein the reference point position is an origin in the X-axis, Y-axis, and Z-axis directions. Energy saving is achieved by machining the workpiece by moving the spindle that grips the tool relative to the workpiece in the three directions of the X, Y, and Z axes perpendicular to each other and cutting off the power to the drive source of the spindle. In the control method of the machine tool to be controlled,
When the machine tool is stopped, the main shaft is held at a reference point position within a preset effective range in the three axis directions of the X axis, the Y axis, and the Z axis, and the main shaft at the reference point position is the X axis and the Z axis. A step that does not interfere with the workpiece in at least one axial direction;
Shutting off the energization to the Y-axis drive source for controlling the movement of the main shaft in the Y-axis direction, which is the vertical axis direction, and operating the brake device when the main shaft is moved to the reference point position;
Detecting the amount of positional deviation of the main shaft in the Y-axis direction while shutting off the power to the Y-axis drive source and operating the brake device;
It is determined whether or not the detected positional deviation amount of the spindle is within the effective range, and the energy saving mode is canceled when the positional deviation amount of the spindle is out of the effective range. Control method. Measuring that a predetermined time has elapsed after the Y-axis drive source is stopped; and
The machine tool control method according to claim 7, wherein it is determined whether or not a displacement amount of the spindle is within an effective range after the predetermined time has elapsed.   The machine tool control method according to claim 7 or 8, wherein the reference point position is an origin position in the X-axis, Y-axis, and Z-axis directions.

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