JPH0276665A - Method and device for controlling work spindle - Google Patents

Abstract

PURPOSE:To prevent a work main shaft motor from emitting heat by furnishing a command means to give a command to a servo control means so that the torque of the work main shaft motor is sunk below the normal rated torque while a clamping means is clamping the revolutions of the work main shaft, and thereby restricting the torque of the work main shaft motor when the work shaft under C-axis control is clamped. CONSTITUTION:In case a work main shaft 10a is clamped in specified angle position under C-axis control, a work command means due to servo control means sinks the torque of the work main shaft motor 10 below the normal rated torque. Even though the servo control means is going to control the drive of the work main shaft motor 10 in clamped condition on the basis of servo error, therefore, there is no fear of overheating of the work main shaft motor 10. Because the servo control means can be also left in operation normally even when the work main shaft 10a is clamped, so that the motion for returning to the point of origin is no more necessary when the work main shaft 10a is clamped or unclamped.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a workpiece spindle control device and control method suitable for application to a built-in workpiece spindle in which a workpiece spindle and a workpiece spindle motor are directly connected.

(b) 4 Prior Art Recently, multi-tasking machine tools that perform turning and C-axis control machining are becoming popular, using a built-in work spindle in which the work spindle and the work spindle motor are directly connected. In the case of such a machine tool, machining may be performed with the workpiece spindle fixed at a constant angle position on the C-axis during C-axis control.

(C) 0 Problems to be Solved by the Invention In this case, if the main shaft drive motor is clamped while the position loop in servo control is still in place, an excessive current will flow through the motor to absorb the servo positioning error, causing the motor to It has the disadvantage of overheating. In addition, to prevent this, it is possible to control the servo to be turned off when clamping, but if the servo is turned off, the accurate C-axis position cannot be reproduced unless the return-to-origin operation is performed again when unclamping. There is a drawback that it cannot be done. Furthermore, a control method is also used in which after the motor is clamped, only the rotation signal from the rotation detector is detected, and control based on the rotation signal is not performed during clamping but is performed when the motor is unclamped.
This control method has the disadvantage that it requires complicated control procedures such as turning on/off the servo and tracking rotation signals.

In order to eliminate the above-mentioned drawbacks, the present invention provides a workpiece spindle control device and control method that does not require a return-to-origin operation when unclamping the spindle drive motor, and does not require complicated control procedures such as turning on and off the servo. The purpose is to provide the following.

(d) Means for solving the zero problem, that is, the present invention provides a workpiece spindle (10a) and a workpiece spindle motor (10) directly connected to the workpiece spindle (10a).
The workpiece spindle (10a) has a workpiece spindle (10a).
A rotation angle detector (15) for detecting the rotation angle of a) is provided, and the C-axis rotation angle of the workpiece spindle motor (10) is controlled according to the signal (S2) from the rotation angle detector (15). A servo control means (7) is provided, and the workpiece spindle (
A clamping means (6, 11) is provided for clamping the workpiece spindle, and while the clamping means is clamping the rotation of the workpiece spindle, the torque of the workpiece spindle motor (10) is lowered than the normal rated torque. A command means (5) for commanding the servo control means is provided.

Furthermore, the present invention has a workpiece spindle (10a) and a workpiece spindle motor (10) directly connected to the workpiece spindle (10a), and the workpiece spindle (10a) is connected to the workpiece spindle (10a).
), and a servo that controls the C-axis rotation angle of the workpiece spindle motor (10) according to a signal (S2) from the rotation angle detector (15). A control means (7) is provided, and the workpiece spindle (1
When the workpiece spindle (10a) is fixed at a predetermined angular position during C-axis control, the clamping means (6, 11) is provided to clamp the workpiece spindle (10a) to the workpiece spindle motor. (10), the workpiece spindle motor (10) is continued to be controlled by the servo control means, and the torque of the workpiece spindle motor (10) is lowered than the normal rated torque, and the workpiece spindle motor (10) is clamped with the workpiece spindle motor (10). 10) It should be configured to prevent heat generation.

Note that the numbers in parentheses are for convenience and indicate corresponding elements in the drawings, and therefore, this description should not be limited to the descriptions in the drawings. r (e) below
The same applies to the column ``, action''.

(e) 0 effect With the above-described configuration, when the workpiece spindle (10a) is clamped under C-axis control, the workpiece spindle motor (10a)
The torque of the workpiece spindle motor (10) is restricted to prevent the workpiece spindle motor (10) from generating heat.

(E), Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 (al is a control block diagram showing an example of a multi-tasking machine tool to which the present invention is applied, (bl is a diagram showing an example of the end face of a workpiece to be machined, FIG. 2 is a diagram showing an example of a cutting program, FIG. 3 is a timing chart showing the timing of each control operation.

As shown in FIG. 1 (al), the multi-tasking machine tool 1 has N
The C device 4 includes a main control section 2, which is connected to a cannibal program memory 3, an axis control section 5, a clamp device control section 6, and the like. A workpiece spindle motor controller 7 is connected to the axis control section 5, and a parameter memory 9 and a workpiece spindle motor 10 are connected to the workpiece spindle motor controller 7. Device 11 is connected.

By the way, the workpiece spindle motor 10 is a workpiece spindle 10a.
A chuck 13 for gripping a workpiece 12 to be machined is attached to the right end of the workpiece main shaft 10a in the figure. Work spindle 10
A rotation angle detector 15 is connected to the workpiece spindle motor controller 7 at the left end of the workpiece spindle 10a, and a clamp plate 11a constituting a clamp device 11 is fixed to the workpiece spindle 10a. Also, chuck 13
On the right side of FIG. 1, a tool rest 16 is provided so as to be movable and driven in the x1Z axis directions, and a rotary tool 17 such as a milling tool, a drill, etc. is removably mounted on the tool rest 16.

Since the multi-tasking machine tool 11!1 has the above configuration, a drill hole is drilled into the end surface 12a of the workpiece 12 mounted on the chuck 13 using a rotary tool 17 such as a drill, as shown in FIG. 12b at a predetermined angular pitch, the main control unit 2 reads out the cannibal program PRO corresponding to the workpiece 12 from the cannibal program memory 3, and drills the cannibal program PRO corresponding to the cannibal program PRO based on the command of the cannibal program PRO. Perform processing on. That is, Canadian program PR
O has a sequence number of N10 as shown in Figure 2.
0, fast forward positioning to the C-axis position θ=45° is commanded (GOOC45), and based on this command, the axis control unit 5 controls the workpiece spindle motor 10 via the workpiece spindle motor controller 7. is controlled by the C-axis, and the workpiece spindle 10a is positioned at a position where θ=45°, which is the position where the drill hole 12b is first drilled. This operation is the third
In the C-axis operation of the time chart shown in Figure (al), it is executed between time T1 and T2.

In this way, at time T2, when the C-axis is positioned at θ=45°, the Canadian program has a sequence number of N1.
At step 01, the control code M210 is output to instruct the clamp device control section 6 to clamp the workpiece spindle 10a. Then, the clamp device control section 6 controls the clamp device 1.
1, the workpiece spindle 1 is positioned at θ-45.
0a is clamped and held at the relevant position by clamping the clamp plate 11a (in Fig. 3 fbl, time T2
3). In this way, when the workpiece spindle 10a is clamped by the clamping device 11 at the C-axis position of θ=45°, a clamp completion signal S1 is output to the axis control section 5. In response to this, the axis control unit 5 instructs the workpiece spindle motor controller 7 to limit the torque of the workpiece spindle motor 10, and the workpiece spindle motor controller 7 receives this and reads out the clamp current value CT from the parameter memory 9. Based on the clamp current value CT, the upper limit of the drive current of the workpiece spindle motor 10 is limited (time T3 in FIG. 3(c)).

Since the clamp current value CT is approximately 5% of the current value corresponding to the rated torque, the torque of the workpiece spindle motor 10 is significantly limited compared to the normal state.

Note that the workpiece spindle motor 10 is the workpiece spindle】Oa is θ=
When the workpiece spindle 10a is positioned at 45°, due to the servo positioning error, the workpiece spindle 10a vibrates little by little around θ=45° and is corrected to θ=45°. Depending on the timing of clamping by the clamping device 11, the main shaft 10a is held in a position slightly (several pulses) deviated from θ=45° in the direction of the C axis.

Even in this clamped state, the device servo loop consisting of the rotation angle detector 15, workpiece spindle motor controller 7, and workpiece spindle motor 10 is alive, and the rotation angle detector 15 detects the workpiece spindle 10a. The C-axis position of is constantly detected and output as a position signal S2 to the workpiece spindle motor controller 7, and the workpiece spindle motor controller 7 receives the position signal S2 and the command value θ=
450, a drive current is applied to the workpiece spindle motor 10. As long as the error between the signal S2 and the command value does not become small, the workpiece spindle motor controller 7 controls the drive current to increase; however, when the clamping device 11 clamps the workpiece spindle 10a, the drive current increases. Since the upper limit of is significantly limited by the clamp current value CT, the workpiece spindle motor controller 7
Even if the drive current to the workpiece spindle motor 10 increases,
Since the clamp current does not increase beyond the clamp current value 07, no excessive torque acts on the workpiece spindle motor 10, thereby preventing the workpiece spindle motor 10 from overheating.

In this way, in the state in which the torque of the workpiece spindle motor 10 is limited between times T3 and 745 in FIG. 3 (cl), the sequence number of the cannibal program shown in FIG.
, N103 causes the axis control unit 5 to drive the tool rest 16,
Drill hole 12b at position θ=45° with respect to workpiece 12
(In Figure 3 (dl), time T
34 and T4).

In this way, when the machining of the drill hole 12b by the rotary tool 17 has been completed, the axis control unit 5 instructs the workpiece spindle motor controller 7 to release the torque limit, and the workpiece spindle motor 10 then cancels the torque limit at time T45. The setting of the clamp current value CT is canceled and the workpiece spindle motor 10 is returned to its normal state. Next, Canada Nibrogram PRO
As shown in FIG. 2, the sequence number enters N104, and based on the control code M212, the clamping device control unit 6 unclamps the clamping device 11 and releases the clamped state of the workpiece spindle 10a. (3rd
Figure (in bl, time T5).

When the unclamp signal S3 indicating that the clamp of the workpiece spindle 10a has been released is output to the axis control unit 5, the axis control unit 5 enters the sequence number N105 of the cannibal program PRO, and then starts drilling the drill hole 12b. A rapid forwarding/positioning operation is started to position the workpiece 12 according to the workpiece spindle 10a1 to the desired C-axis position θ=1350 (
FIG. 3 (time T6 in al). At this time, the workpiece spindle motor 10 is driven in a state where the restriction by the clamp current value CT is released, so that the rapid forwarding and positioning operations can be performed smoothly. Even when the workpiece spindle 10a is clamped by the clamp device 11, the servo loop of the workpiece spindle motor 10 via the rotation angle detector 15 and the workpiece spindle motor controller 7 continues to operate.
Work spindle motor yoto. -Rough is always workpiece spindle 10
The current C-axis position of a is recognized. Therefore, when the clamp device 11 is unclamped, it is possible to immediately start the next C-axis positioning operation without performing a return-to-origin operation.

Note that when performing normal turning with the multitasking machine tool 1, the workpiece spindle motor 10 is rotated at a predetermined rotation speed, and the workpiece 12 gripped by the chuck 13 is moved to the tool post 16.
Machining with the above turning tool.

(g) 0 Effects of the invention As explained above, according to the invention, the workpiece spindle 1
0a and a workpiece spindle motor 10 directly connected to the workpiece spindle 10a.
A workpiece spindle motor controller 7 or the like is provided with a rotation angle detector 1'5 for detecting the rotation angle of 0a, and controls the C-axis rotation angle of the workpiece spindle motor 10 in accordance with the signal S2 from the rotation angle detector 15. a clamping device 11 provided with a servo control means and clamping the workpiece spindle 10a;
A clamping means such as a clamp device control section 6 is provided, and the servo control means is configured to reduce the torque of the workpiece spindle motor 10 below the normal rated torque while the clamping means clamps the rotation of the workpiece spindle 10a. Since the configuration is provided with a command means such as the axis control unit 5 for commanding the C-axis, when the workpiece spindle 10a is clamped at a predetermined angular position during C-axis control, the control state of the workpiece spindle motor 10 by the servo control means is not released. In both cases, the torque of the workpiece spindle motor 10 is reduced relative to the normal rated torque, so even if the servo control means tries to drive and control the workpiece spindle motor 10 in the clamped state based on the servo error, the workpiece spindle motor 10 will not overheat. There's nothing to do. Furthermore, since the servo control means can be kept operating at all times even when the workpiece spindle 10a is clamped, when the workpiece spindle 10a is clamped or unclamped, not only is there no need for a return-to-origin operation, but the servo control is turned on. , there is no need for a complicated control procedure to turn it off.

It also has a workpiece spindle 10a and a workpiece spindle motor 10 directly connected to the workpiece spindle 10a.
A rotation angle detector 15 for detecting the rotation angle of the workpiece spindle 10a is provided at 0a, and the signal S from the rotation angle detector 15 is
2, a servo control means such as a workpiece spindle motor controller 7 for controlling the C-axis rotation angle of the workpiece spindle motor 10 is provided, and clamping means such as a clamp device 11 and a clamp device control unit 6 for clamping the workpiece spindle 10a are provided. When fixing the workpiece spindle 10a at a predetermined angle position during C-axis control, the clamping means is driven to clamp the workpiece spindle 10a together with the workpiece spindle motor 10, and the workpiece spindle is controlled by the servo control means. Continues to control the motor 10, and further controls the workpiece spindle motor 1.
0 torque is lower than the normal rated torque to prevent the workpiece spindle motor 10 from generating heat, the torque of the workpiece spindle motor 10 is limited, and the servo control remains on. In this state, the workpiece spindle 10a can be clamped.

[Brief explanation of the drawing]

Fig. 1 fat is a control block diagram showing an example of a multi-tasking machine tool to which the present invention is applied; Figure 3 is a timing chart showing the timing of each control operation. 5... Command means (axis control section) 6... Clamp means (clamp device control section) 7.
Servo control means (workpiece spindle motor controller) 10... Workpiece spindle motor 10a... Workpiece spindle 11... Clamping means (clamping device) 15...
Rotation angle detector S2...Signal applicant Yamazaki Mazak Co., Ltd. Figure 1 (G)

Claims (2)

[Claims] (1) It has a workpiece spindle and a workpiece spindle motor directly connected to the workpiece spindle, the workpiece spindle is provided with a rotation angle detector for detecting the rotation angle of the workpiece spindle, and the workpiece spindle is responsive to a signal from the rotation angle detector. a servo control means for controlling the C-axis rotation angle of the workpiece spindle motor, and a clamping means for clamping the workpiece spindle, and while the clamping means clamps the rotation of the workpiece spindle, the workpiece spindle motor is rotated. A workpiece spindle control device comprising command means for instructing the servo control means to reduce torque below a normal rated torque. (2) has a workpiece spindle and a workpiece spindle motor directly connected to the workpiece spindle; the workpiece spindle is provided with a rotation angle detector for detecting the rotation angle of the workpiece spindle; a servo control means for controlling the C-axis rotation angle of the workpiece spindle motor, and a clamping means for clamping the workpiece spindle, and when the workpiece spindle is fixed at a predetermined angular position during C-axis control, the clamping means is to clamp the workpiece spindle together with the workpiece spindle motor, continue controlling the workpiece spindle motor by the servo control means, further reduce the torque of the workpiece spindle motor below the normal rated torque, and reduce the torque of the workpiece spindle motor. A workpiece spindle control method configured to prevent heat generation.