JPH0698521B2 - Numerical control device for combined machining lathe - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control (hereinafter simply referred to as NC) device for a composite machining lathe having a sub-spindle facing a main shaft.

(Prior Art) Generally, in a multi-tasking lathe having two opposing spindles, a main spindle (hereinafter referred to as a main spindle) and a pick-off spindle (hereinafter referred to as a sub-main spindle),
The first process is performed on the main spindle, and the second process (for example, back surface processing) is performed on the sub-spindle. Then, when moving from the first process to the second process, the sub-spindle is brought close to the main shaft to directly deliver the work. At this time, since it is necessary to match the C-axis machining angles in the combined machining in both steps, the rotation of the main spindle and the sub-spindle is once stopped and the positions in the C-axis direction are aligned, and then the work is transferred. In other words, the turning of the last of the first step and the beginning of the second step, even if it is not necessary to stop the spindle for machining, it is necessary to stop the spindle when transferring the work and then rotate the spindle again. This has the drawback that the processing time is long.

(Problems to be Solved by the Invention) If the work can be delivered while the spindle is still rotating, it is possible to save the time for stopping the spindle and then rotating it again. For that purpose, in order to stably grasp the work held by the main spindle during rotation with the sub spindle, the function to keep the relative positional relationship between the main spindle and the sub spindle constant, that is, the sub spindle synchronizes with the main spindle. The function to rotate is required. This synchronous rotation is performed by controlling the position of the sub spindle based on the position of the spindle. Since the number of points is the same in the synchronous rotation, the main shaft and the sub-main shaft rotate while maintaining a constant phase difference. This phase difference does not change during synchronous rotation, but it differs each time synchronous rotation occurs. Since the work is delivered at the position shifted by this phase difference,
It is necessary to have a function of correcting the phase difference during combined machining on the sub-spindle side (second step) so that the C-axis machining angles in the combined machining in the first step and the second step match.

The present invention has been made under the circumstances as described above, and an object of the present invention is to make the C-axis machining angles in combined machining of both shafts the same even when the work is delivered while the main shaft and the sub-spindle are rotating. To provide an NC device for the combined machining lathe.

(Means for Solving the Problem) The present invention is for a composite machining lathe having a sub-spindle facing the main spindle.
Regarding the NC device, the above object of the present invention is to provide position detecting means on each of the main spindle and the sub-spindle, and when the main spindle and the sub-main spindle pass between the rotating workpieces between the main spindle and the sub-main spindle, By storing the difference of each of the position detecting means during the rotation in the storage means, and by adding the difference data stored in the storage means to the position indexing control in the spindle passed the work, This is achieved by aligning the phases of position indexing on the main and sub-main axes.

(Operation) A position detector is attached to the main shaft, and the sub-spindle performs position control. The sub-spindle is on the axis that moves in the longitudinal direction, and the sub-spindle rotation speed matches the main-spindle rotation speed of the main spindle that grasps the workpiece. Next, the sub-spindle is position-controlled based on the position of the main-spindle and is rotated synchronously. However, since this only adjusts the rotational speed, both shafts rotate while maintaining a constant phase difference.
The chuck of the sub-spindle is closed to grasp the work, and both shafts are connected through the work. At this time, the phase difference is obtained and held from the values of the detectors of both axes, and the phase difference is corrected in the C-axis movement of machining on the sub-spindle so that the C-axis machining angles of both axes match. be able to.

(Example) FIG. 1 is a structural diagram of a main spindle 1 and a sub-spindle 7 facing each other.
The work 6 is transferred between these two axes. That is, the chuck 2 is mounted on the main shaft 1, the chuck 2 grasps the work 6, and the chuck 8 is mounted on the sub-main shaft 7. The present invention allows the chuck 8 to grasp the workpiece 6 grasped by the chuck 2 while the main spindle 1 and the sub-main spindle 7 are rotating. Main controller 12
Based on the command from the main shaft motor drive unit 4 and the sub main shaft motor drive unit 10, the main shaft motor 3 and the sub main shaft motor 9 are respectively driven, and the rotations of the motors 3 and 9 are transmitted to the main shaft 1 and the sub main shaft 9, respectively. The main shaft 1 and the sub-spindle 9 are rotationally driven by. The position detectors 5 and 11 detect the rotational positions of the main shaft 1 and the sub main shaft 7, respectively. Position detector 5
The position detection signals MPS and PPS of 11 and 11 are input to the main controller 12, and the main controller 12 outputs a rotation command MDS as a command of the main spindle motor 3 and a rotation command PDS as a command of the sub-spindle motor 9. .

Here, the work 6 while the main shaft 1 and the sub-spindle 7 are rotating.
In order to deliver, the two axes must be in a relatively constant position. In order to keep the main spindle 1 and the sub-spindle 7 that are rotating by speed control at a constant position, the main spindle 1 performs position control with the main spindle position as a position command value for the sub-spindle 7, and both axes are synchronized. Need to rotate. In order to rotate the sub-spindle 7 synchronously during the main-spindle rotation, in order to avoid sudden acceleration / deceleration, first, the rotational speed of the sub-spindle 7 is adjusted to the rotational speed of the main spindle 1, and when the rotational speeds match, the position of the main spindle 1 is adjusted. So that they rotate synchronously. Since the sub-spindle 7 is position-controlled as described above, control for rotating the sub-spindle 7 at a constant speed is also performed by obtaining the position command value. In this case, the speed command amount corresponding to the rotation speed is sequentially added to the position command value to obtain the position command value. The main spindle rotation speed is rotated as the target rotation speed of the sub-spindle 7, and when the rotation speed becomes the same, the position command value is switched from the position command value obtained from the main spindle rotation speed to the position command value obtained from the main spindle position for synchronous rotation. to go into. However, since the above two position command values obtained from different elements do not match,
If you leave it as it is, you cannot switch smoothly.

FIG. 5 shows the positional relationship when the sub-spindle 7 has the same rotational speed as the main spindle 1, and at this time, the chuck 8 of the sub-spindle 7 is rotated.
Is still open. The circle on the right side in FIG. 5 is the C-axis coordinate centered on the point O. A point M on the chuck 2 is a reference point of the spindle 1, a point P on the chuck 8 is a reference point of the sub-spindle 7, a point PM is a C axis coordinate position of the reference point M, and a point PP is a C axis coordinate position of the reference point P. And It is assumed that the clockwise direction when viewing FIG. 5 from the left to the right is the C-axis increasing direction, and both the main shaft 1 and the sub-main shaft 7 are rotating in the C-axis increasing direction.

It should be noted that "CV" is a position command value for the sub spindle 7 determined from the spindle rotation speed. Since the sub spindle 7 is rotating according to the position command value CV at this point, the point PP is delayed from the position command value CV by the delay control position θ _D including a dynamic error. Then, "CM" is a position command value for synchronous rotation obtained from the spindle position. Therefore, CM = PM (1) and there is a phase difference θ _C between the position command value CV and CM as shown in the following equation.

θ _C = CV-CM (2) Then, assuming that the position command value used for position control of the sub spindle 7 is C, from formula (2) C = CV (3) C = CM + θ _C (4) ), And when rotating at the same speed as the spindle 1, (3)
After switching to the formula and the synchronous rotation, it is possible to smoothly switch by obtaining the position command value according to the formula (4).

After starting the synchronous rotation, the chuck 8 on the side of the sub-spindle 7 is closed. As a result, the relative positions of the main shaft 1 and the main shaft 7 are mechanically fixed. In FIG. 6, the chuck 8 of the sub spindle 7 is closed. The relative positions of the points PM and PP are fixed, and the phase difference θ _P of the following equation exists between the points.

θ _P = PM-PP (5) Since the point PP lags the point PM by θ _{P in} this way, the workpiece 6 is grasped by the chuck 8 of the sub-spindle 7 while being advanced by θ _P. Has been done. Then, the chuck 2 on the spindle 1 side is opened, and the transfer of the work 6 is completed. From the above,
At the time of C-axis positioning in the combined machining on the sub spindle 7 side, the C axis machining angle in the combined machining of the spindle 1 and the sub spindle 7 can be made equal by subtracting the phase difference θ _P from the position command value. .

FIG. 2 shows a circuit system for rotation control of the main shaft 1 and the sub-spindle 7
It is a figure shown corresponding to a figure, and the command analysis part 20 is analyzing so that the command with respect to the main controller 12 can be executed in each control part. The spindle rotation control unit 21 outputs a rotation command MDS to the spindle motor drive unit 4 based on the spindle rotation command from the command analysis unit 20, and the spindle rotation speed calculation unit 22 outputs the position detection signal MPS from the position detector 5. The rotational speed MR of the spindle 1 is calculated by. Further, the sub spindle rotation speed calculation unit 23 calculates the rotation speed PR of the sub spindle 7 based on the position detection signal PPS from the position detector 11. The rotation speed comparison unit 24 then calculates the calculated spindle rotation speed.
MR and the sub spindle rotational speed PR are compared, and when the same rotational speed is reached, a coincidence signal CN is input to the command phase difference calculation unit 25 and the sub spindle position command switching unit 31. The command phase difference calculator 25 calculates the phase difference θ _C between the position command value CM obtained from the spindle position used for synchronous rotation and the position command value CV used for sub-spindle rotation control when both shafts have the same rotational speed. And outputs it to the synchronization control unit 28. The chuck control unit 26 opens and closes the chucks 2 and 8 according to the chuck opening / closing command CK from the command analysis unit 20,
When both chucks 2 and 8 on both axes are closed, a closing signal CS is input to the position / phase difference calculating unit 27. The position / phase difference calculating unit 27 uses the input closed signal CS as a trigger to calculate the position phase difference θ _P based on the position detection signals MPS and PPS from the position detectors 5 and 11 for both axes, and calculates the position phase difference θ _P. C-axis positioning controller 30
To enter. The sub spindle rotation control unit 29 is a main spindle rotation speed calculation unit.
The speed for each position control unit time is calculated so as to be the same rotation as the spindle rotation speed MR obtained in 22, and the position command value CV of the sub spindle 7 is formed. Further, the synchronization control unit 28 adds the command phase difference θ _C calculated by the command position calculation unit 25 as a correction amount to the position command value CM calculated from the spindle position to calculate the synchronous rotational position command value.

By configuring the main controller 12 in this way, it is possible to perform smooth switching without changing the position command value abruptly when switching from the rotation control to the synchronous control. When performing composite machining on the sub-spindle 7 side, the sub-spindle / C-axis positioning control unit 30
Axial positioning control is performed. At that time, the position phase difference θ _P obtained by the position phase difference calculation unit 27 is subtracted from the position command value as a correction value, and the C-axis machining angle between the main spindle 1 and the sub-spindle 7 is calculated. Match on above. The sub spindle position command switching unit 31 determines which of the positioning control unit 30, the sub spindle rotation control unit 29, and the synchronization control unit 28 based on the coincidence signal CN from the rotation speed comparison unit 24 and the command from the command analysis unit 20. It is determined whether to use the position command value, and the position command value C is transmitted to the sub spindle position control section 32. Based on the position command value C, the sub spindle position control unit 32 determines the sub spindle 7
The C-axis position control is performed.

The flowchart of FIG. 3 shows the operation of delivering the work 6. Synchronous rotation “ON” processing (step S1)
A process for rotating the sub spindle 7 in synchronization with the rotating main spindle 1 is performed. Details will be described with reference to FIG. And
When the main spindle 1 and the sub spindle 7 rotate in synchronization, the chuck 8 on the sub spindle 7 side is then closed (step S2). As a result, the relative positions of the main shaft 1 and the sub main shaft 7 are mechanically fixed through the work 6. In this state, the phase difference θ _P between the main spindle position and the sub-spindle position is obtained and held (step S3). next,
The chuck 2 on the spindle 1 side is opened (step S4), and the work 6 is now transferred from the spindle 1 to the sub spindle 7. After that, the synchronous control is switched to the rotational control so that the rotational speed before the synchronous rotation is reached. As a result, it is possible to start turning as it is with only the sub spindle 7. Furthermore, when the cutting process becomes a combined process, the spindle 1 is corrected by correcting the phase difference obtained in step S3 in the C-axis positioning.
It is possible to match the C-axis machining angles of the combined machining on the side and the sub-spindle 7 side on the work 6.

The flowchart of FIG. 4 shows a processing example of the synchronous rotation “ON” of the sub spindle 7 which is step S1 of FIG. The sub-spindle rotation control unit 29 controls so that the sub-spindle 7 rotates at the rotation speed MR calculated by the main-spindle speed calculation unit 22 (step S1).
0). When the actual rotational speeds of the main spindle 1 and the sub-spindle 7 match (step S11), the synchronization control unit 28 determines the C-axis synchronous control position command value CM of the sub-spindle 7 formed from the main spindle position and the rotation control at this point. C-axis position command value CV of constant speed formed in part 29
Then, the phase difference θ _C between and is obtained (step S12). Next, the selection of the C-axis position command is switched from rotation control to synchronous control (step S13), and the phase difference θ _{C is} added to the position command value CM to obtain the C-axis command value C (step S14). This completes the synchronous "ON" processing, and thereafter the sub spindle 7 rotates in synchronization with the spindle 1.

In this example, the case where the work is transferred from the main spindle to the sub-spindle has been described, but conversely, the case where the work is transferred from the sub-spindle to the main spindle may be considered in the same manner.

(Effect of the Invention) As described above, according to the present invention, it is possible to directly transfer a workpiece between two opposing shafts and perform back surface machining, and in NC control combined machining lathe, from machining on the spindle side to sub-spindle side. Since there is no need to stop the spindle and rotate it again when shifting to machining, machining time can be shortened accordingly.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of two opposing main spindles and sub-spindles, FIG. 2 is a block diagram showing a control system thereof, FIG. 3 is a flowchart showing work transfer, and FIG. 4 is a sub-spindle main spindle. A flow chart showing an example of control for synchronous rotation with
5 and 6 are diagrams for explaining the positional relationship when the main shaft and the sub-spindle are rotating at the same rotation speed. 1 ... spindle, 2,8 ... chuck, 3 ... spindle motor, 4
...... Spindle motor control section, 5,11 ...... Position detector, 6 ...... Workpiece, 7 ...... Spindle, 12 ...... Main control unit, 20 ...... Command analysis section, 21 ...... Spindle rotation control section, 24 ...... Rotation speed comparison unit, 28 …… Synchronization control unit.

Claims (1)

[Claims] 1. A numerical control combined machining lathe having a sub-spindle facing a main spindle, wherein position detecting means is provided on each of the main spindle and the sub-main spindle, and the main spindle and the sub-main spindle are rotating between the main spindle and the sub-main spindle. When the work is transferred, the difference between the respective position detecting means during the rotation is stored in the storage means, and the difference stored in the storage means is used for the position indexing control of the passed spindle. A numerical control device for a multi-tasking lathe, characterized in that the phase of position indexing on the main spindle and the sub-spindle is matched by adding data.