JPH0327333B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a tool feed control device for a turning machine, and in particular, to a tool feed control device for a turning machine, in particular, while a cylindrical workpiece in a rotating state is within a certain angular phase range, The tool is moved in a specific direction from a fixed position reference point in synchronization with the rotation of the tool, and the tool is rapidly retreated to the position reference point while the tool is out of the range of the fixed angular phase. The present invention relates to a tool feed control device in a turning machine.

<Prior art> The lower cylinder that guides the tape in a video tape recorder has a cylindrical shape as shown in FIG. A lead surface S is formed. As shown in FIG. 2, the position of this lead surface S in the axial direction changes linearly with respect to changes in the angular position in the angular range of 0 DEG to .theta.1 where the lead surface S actually contacts the tape.

Conventionally, in order to process the lead surface S with high efficiency, machining was performed by copying, but in such a machining device using copying,
Not only is manufacturing a cam troublesome, but in order to obtain highly accurate linearity, it is generally necessary to perform trial machining with the cam once manufactured, measure the shape of the workpiece, and install it based on the measurement results. Since the cam surface of the cam is slightly corrected on the machine, the cam must be made of raw material, which shortens the life of the cam, and increases the wear of the cam surface when the main shaft rotates quickly. Because of this, the spindle could not be rotated quickly and machining efficiency could not be improved much.

It is also conceivable to machine the lead surface S by moving the tool in a direction parallel to the axis of the workpiece W in synchronization with the rotation of the workpiece W using numerical control; As is also clear, the angle θ1
~θ2, machining accuracy is not so required, but the rate of change in position of the lead surface S with respect to changes in the angle of the workpiece is very large, so in order to improve machining efficiency, the rotation speed of the workpiece W is increased and the machining accuracy is increased. If the amount of movement per pulse is made small in order to improve this, the pulse distribution for moving the tool in this θ1 to θ2 region will not be enough, and
It has not been possible to increase the rotational speed of the workpiece W to improve machining efficiency.

<Objective of the Invention> Therefore, the present invention aims to move the tool support at a speed faster than the maximum pulse distribution speed of the numerical control device in an angular range where the ratio of the change in position of the lead surface to the change in the angular position of the workpiece is significantly large. The purpose is to increase the rotational speed of the spindle by making it movable, thereby significantly improving machining efficiency.

<Structure of the Invention> The present invention provides an angular phase detection means for detecting when the angular phase of a workpiece reaches the start and end points of a certain range, and a position detection means for detecting that the tool is located at a position reference point. a servo motor linked to the tool feeding mechanism; a signal sending means for sending a control signal to the servo motor in response to a numerical command pulse; activating the signal emitting means in response to detecting that the starting point has been reached;
interrupting means for interrupting a control signal for the signal emitting means in response to detecting that the workpiece has reached the end of the angular range; pulse distributing means for distributing numerical command pulses in accordance with numerical data; and a control signal for generating a control signal for rotating the servo motor at high speed in a direction toward or backward from the position reference point while out of the range. It is equipped with a generating means.

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 4, reference numeral 10 indicates the base of the turning processing device, and on the right side of the base 10 there is a workpiece W.
A headstock 11 that supports the guide table 1 is placed on the left side facing the headstock 11, and a tool support 13 to which a tool T such as a cutting tool is attached is mounted on the guide table 1.
5 and the base 10 via the slide table 16
supported above.

A main spindle 20 is rotatably supported on the headstock 11 by a hydrodynamic bearing, and a chuck 21 for supporting the workpiece W while determining the phase thereof is attached to the tip of the main spindle 20 on the side facing the guide stand 15. ing.

The main shaft 20 is rotationally driven by a main shaft motor 22 attached to the rear surface of the headstock 11. Also, the displacement detector 23 attached to the rear end of the main shaft motor 22 detects the movement of the main shaft 2.
0 rotation is detected, and spindle 2
When 0 reaches a specific angular phase, the displacement detector 23
An origin pulse ZP is output from the displacement detector 23, and a rotation pulse RP is output from the displacement detector 23 each time the main shaft 20 rotates by a unit angle. Furthermore, the headstock 1
The cutting table 12 on which the head 1 is placed is connected to a servo motor 25 attached to the right end of the base 10 via a screw feed mechanism (not shown), and the rotation of the servo motor 25 causes the headstock 11 to be parallel to the spindle axis. be advanced or retreated in a certain direction.

On the other hand, the slide table 16 has a base 10
It is guided and supported at the top so that it can move in a direction perpendicular to the spindle axis, and is connected to a servo motor 26 attached to the side surface of the slide base 17 via a screw feeding mechanism (not shown). A guide stand 15 is attached.

The guide stand 15 is provided with a tool support 13 having a rectangular cross section and a tip end protruding toward the headstock 11 side.
is guided and supported by a pair of static pressure bearings so as to be movable in a direction parallel to the spindle axis, and this tool support 13 is screwed into an unillustrated feed screw rotated by a servo motor 18, Motor 1
It is designed to be moved forward and backward by the rotation of 8.
Incidentally, the servo motor 18 and the servo motors 25 and 26 are respectively attached with speed detectors 18a, 25a and 26a for speed feedback and resolvers 18b, 25b and 26b for detecting rotation amount.

Furthermore, an absolute position detector 19 for detecting the absolute position of the tool support 13 is attached to the guide stand 15 and is linked to the tool support 13 feeding mechanism. This absolute position detector 19 outputs the amount of movement of the tool support 13 as a digital signal, with the point where the tool T is located at the reference origin PO, which is a position reference point, as a zero point.

Next, to explain the control circuit, in FIG. is a profile data area PDA for storing the shape of the lead surface S to be formed;
Numerical control data area that stores cutting depth data, etc.
NCDA is formed and the interface IF
Data is written into the profile data area PDA and the numerical control data area NCDA by a data input device 32 connected to the numerical control device main body 30 via 1. The data written in the profile data area PDA is the number of pulses representing the amount of movement of the tool support 13 while the spindle 20 rotates by a unit angle, as shown in FIG. 6, and indicates that the spindle 20 is located at the origin. Only the state, that is, the data from the angular position where the rotation angle of the workpiece W becomes 0° until the angular phase of the workpiece W reaches θ1, are written in order from address m.

Further, the output of the displacement detector 23 is connected to the numerical control device main body 30 via the interface IF1, and the servo motors 18, 25,
A pulse distribution circuit 33, a pulse generation circuit 34, and a pulse generation circuit 35 that distribute command pulses to a drive unit DUZ, a drive unit DUX, and a drive unit DUO that drive the drive unit 26, respectively, are connected via an interface IF2. These pulse generation circuits 34, 35, 36 are speed registers.
An FR and a pulse number register VR are provided, and speed data and pulse distribution number data are respectively set from the numerical control device main body 30. Thereafter, when a distribution start command is given from the numerical control device main body 30, the commanded number of pulses are distributed at the commanded speed. Additionally, the interface IF
2 is also connected to the output of the absolute position detector 19.

The drive units DUZ, DUX, and DUO have the same structure as before, and as shown in FIG. 7, the numerical command pulses output from the pulse generation circuits 33 and 34
Feedback pulse output from feedback pulse generation circuit 43 connected to NCP and resolvers 25b, 26b
FBP is input into the deviation counter 40 to detect the deviation between the two, and the output of this deviation counter 40 is used as the DA.
A converter 41 converts it into an analog command voltage, a calculator 44 calculates the deviation between this and the feedback voltage output from the speed detectors 25a and 26b, and a voltage corresponding to this deviation is sent to a servo amplifier 45. The servo motor 25 or 26 is rotated by supplying the servo motor 25 or 26.

On the other hand, the drive unit DUO drives the servo motor 1 according to the numerical command pulse NCP as shown in Fig. 8.
The first operation mode rotates the servo motor 8 and the servo motor 1 rotates when the numerical command pulse NCP is not supplied.
In addition to the above circuit, the output of the absolute position detector 19 that detects the absolute position of the tool support 13 is A DA converter 46 that converts into an analog signal, and analog gates AG1, AG2 and A high-speed retreat command is supplied from the adder 47, the low pulse filter 42 connected to the output of the adder 47 to alleviate sudden level changes in the command signal supplied to the arithmetic unit 44, and the numerical control device main body 30. a one-shot circuit 48 that resets the deviation counter 40 at the point in time, and a gate that disables the output of the feedback pulse generation circuit 43 from when the tool support 13 starts its backward movement until it is located at the reference origin.
DG and OR gate OR etc. are provided.

Flip-flops FF1 and FF2 are flags for mode storage, and
A release signal is given from 0 and the flip-flop
The first state is when both FF1 and FF2 are reset.
This is the operating mode, and in this state, both analog gates AG1 and AG2 are closed, and
When the gate DG is opened, the circuit operates as a normal drive circuit shown in FIG. 7, and the servo motor 18 is rotated accurately by an amount corresponding to the number of pulses at a speed corresponding to the frequency of the numerical command pulse NCP.

On the other hand, when a rapid retreat command is output from the numerical control device main body 30 and flip-flop FF1 is set, the second operation mode is entered, and the analog gate
AG1 is opened and the command voltage VC is supplied to the adder 47, while the deviation counter 40 is reset and the output of the DA converter 41 becomes zero. As a result, the command voltage VC is supplied to the arithmetic unit 44, and the servo motor 18 is rotated at high speed in a direction to move the tool support 13 backward.

In addition, the numerical control device main body 30 determines that the tool support 13 is at the reference origin based on the output of the absolute position detector 19.
When it is detected that the deceleration point PD, which is a certain distance away from PO, is output and a deceleration command is output, flip-flop FF2 replaces flip-flop FF1.
is set, and the output of the DA converter 46 is sent to the adder 4.
7 will be supplied. As a result, as shown in FIG. 14, the adder 47 outputs a value that decreases as the tool support 13 approaches the reference origin PO.
A command signal that becomes zero when the reference origin point PO is reached is output, and the servo motor 18 is rapidly decelerated.

When the numerical controller main body 30 detects that the tool support 13 has reached the reference origin PO and outputs a release signal, the flip-flop FF1,
FF2 is reset and returns to the first operating mode described above. In addition, the output of command voltage VC and DA
The output of the converter 46 indicates that the tool support 13 is at the deceleration point.
Both outputs are set to be equal when located at PD.

Next, the overall operation will be explained based on the flowcharts shown in FIGS. 9 to 12.

Now command the numerical control device main body 30 to start machining.
When START is given, the numerical control device main body 30
At step (50) in FIG. 9, the tool T is moved so that the tip of the tool T is spaced a certain distance C from the end surface of the workpiece W and at a certain distance from the outer peripheral surface of the workpiece W, as shown in FIG. After distributing pulses to position the machining start position close to the axis by a depth of cut d, in step (51), pulses are distributed to the Z-axis, which is the cutting axis, from the cutting speed data input in advance. The distribution speed is calculated and the Z-axis pulse distribution circuit 33
Then, in step (52), the cutting completion flag IFF is reset and the total cutting depth _FT is set in the cutting counter IFC for detecting the cutting depth. Then, in step (53), the distribution number data stored in the first address of the profile data area PDA is read out, and the pulse distribution speed at which the pulse distribution is completed immediately before the workpiece W rotates by a unit angle is set. After that, in step (55), a backward release signal is output to the drive unit DUO, and the drive unit is
Place the DUX in the first operating mode and step (56)
Wait until the origin pulse ZP is sent out from the displacement detector 23.

Then, when the origin pulse ZP is sent from the displacement detector 23, the numerical control device main body 30 executes the program shown in FIG. 10, and confirms that the cutting completion flag IFF has been reset in step (60). After that, in step (61), the numerical control flag NCCF indicating that the control mode is the numerical control mode is set, and the angle detection counter ADC for detecting the rotation angle of the workpiece W is reset to zero, and steps (62) to ( 66) performs processing for pulse distribution. That is, the pulse distribution speed data calculated in advance in step (62) is set in the speed register FR of the O-axis pulse generation circuit 35 in step (62), and the pulse distribution speed data calculated in advance in step (53) is set in the speed register FR of the O-axis pulse generation circuit 35. The distribution number is set in the pulse number register VR of the pulse generation circuit 35 in step (63), and then a pulse distribution start command is output to the pulse generation circuit 35 in step (64). As a result, pulses for profile creation are sent from the pulse generation circuit 35 and supplied to the O-axis drive unit DUO.
The tool support 13 is given movement for shape creation. Thereafter, the process moves from step (64) to step (65), and data on the number of pulse distribution corresponding to the next angular position is read out from the profile data area PDA, and the pulse distribution is performed while the spindle 20 rotates by a unit angle. At step (66), the pulse distribution speed is calculated so that the pulse distribution is completed, and the process returns to the main routine (not shown).

Through the above process, the tool support 13 is moved by a predetermined amount to the right in FIG. 13 from the reference origin PO in synchronization with the rotation of the workpiece W, and the profile creation movement is started.

Thereafter, when the workpiece W rotates by a unit angle and the rotation pulse RP is output from the displacement detector 23, the numerical control device main body 30 executes the program shown in FIG. After advancing the detection counter ADC, steps (71), (72)
, the rotation phase of the workpiece W is at an angle θ1 that causes the tool support 13 to rapidly retreat, or a tool cutting angle θ3 that is slightly before the original position of the workpiece W, with reference to the count value of the angle detection counter ADC. If it is not, the numerical control flag NCCF is set in step (73).
Make sure that is set, move on to step (61) in Fig.
Execute the pulse distribution process again.

As a result, until the rotational phase of the workpiece W reaches θ1, the program in steps (61) to (66) is executed every time the workpiece W rotates by a unit angle, and the profile data stored in the memory 31 is updated. A compliant pulse distribution takes place. Since the drive unit DUO is in the first operation mode in which the servo motor 18 is rotated according to the numerical command pulse, the servo motor 18 is accurately rotated in synchronization with the rotation of the workpiece W according to the profile data. Add profile creation movement to T.

When the workpiece W rotates to θ1, the numerical control device main body 30 determines this in step (71) in FIG. 11, moves from step (71) to step (75), and rotates the tool support 13 Perform processing to rapidly retreat. i.e. step (75)
After resetting the numerical control flag NCCF at step (76), a rapid backward command is output to the drive unit DUO, and the drive unit DUO
switch to the second operating mode. As a result, the arithmetic unit 44 in the drive unit DUO includes an analog gate AGI, an adder 47, and a low pulse filter 42.
A command voltage VC is supplied through the servo motor 18, and the servo motor 18 is rotated at high speed in a direction that moves the tool support 13 to the left in FIG. 13, and the tool support 13 is moved at a high speed toward the reference origin PO.

When the tool support 13 starts to retreat in this way, the deceleration point detection routine shown in FIG. 12 is executed at regular intervals, and it is detected in step (92) that the tool support 13 has reached the deceleration point. When it is done,
In step (93) of this routine, the drive unit
Outputs deceleration command signal to DUO. As a result, the analog gate in the drive unit DUO is switched, the output of the DA converter 46 is supplied to the adder 47, the servo motor 18 is rapidly decelerated, and when the tool support 13 reaches the reference home position, the servo motor 18 is rapidly decelerated. ,
The output of the DA converter 46 becomes zero and the rotation of the servo motor 18 is stopped.

The rapid retraction of the tool support 13 due to this process is
Completed before the workpiece W reaches the cutting angle position θ3,
After this, the numerical control device main body 30 waits until the workpiece W reaches θ3, and when the workpiece W reaches θ3, the first
When detected at step (72) in Figure 1, the process moves from step (72) to step (79) via step (78), and then to step (79) and step (80).
Processing is performed to distribute cutting pulses of the number corresponding to the cutting depth ΔC to the drive unit DUZ. Then, in step (83), the profile data readout start position is set in the profile data area PDA.
After resetting it to the first address, the process moves to step (53) in Figure 9, and in steps (53) and (54), the process of calculating the number of pulse distribution and the speed corresponding to the number of pulse distribution is performed. Then, in step (55), a retreat release command is output to the drive unit DUO to return the drive unit DUO to the first operation mode.

Then, when the workpiece W further rotates from this state and returns to the home position state again, the numerical control device main body 30 again executes the program shown in FIG. Processing is performed to move the support body 13 in synchronization with the rotation of the workpiece W.

By repeating the above operations, the outer peripheral surface of the workpiece W is gradually cut from the end surface side, and the cutting table 12
When the lead surface S is cut by a predetermined depth of cut F _T , a lead surface S having a shape according to the profile data stored in the profile data area PDA is formed at a predetermined position on the outer peripheral surface of the workpiece W.

In the process of creating this lead surface S, during the retraction process of the tool support 13 in which the amount of movement of the tool support 13 increases with respect to changes in the rotation angle of the workpiece W, that is, when the angular position of the workpiece W is between θ1 and θ2. Since the servo motor 18 is rotated at high speed by applying an analog command voltage to the servo amplifier instead of a pulse command, the main shaft 2
A rotation speed of 0 means that the amount of movement of the tool support 13 relative to changes in the rotation angle of the workpiece W is not so large between 0° and θ1.
During this period, the processing speed can be increased to the extent that the pulse distribution processing can be performed by the numerical control device main body 30, and the processing can be completed within a short time.

In this way, when the workpiece W rotates once with the cutting table 12 cutting by the commanded total depth of cut, this is detected at step (78) in FIG. 11 and the cutting completion flag IFF is flagged. is set, and after this, when the workpiece W is in the original position and the program shown in Fig. 10 is executed, this is the step (60).
is detected, the tool T is separated from the machining surface, and the machining cycle is completed.

Note that in the above embodiment, in the first operation mode,
By adding a constant voltage to the output of the DA converter 41, a predetermined analog voltage is applied to the arithmetic unit 44 to rotate the servo motor 18 at high speed, but the deviation counter 40 is preset to a constant value. The predetermined analog voltage may be applied to the arithmetic unit 44 by another method such as.

<Effects of the Invention> As described above, in the present invention, the drive unit that drives the servo motor for moving the tool support can be operated in the first operation mode in which the servo motor is rotated in accordance with a numerical command pulse, and in the servo amplifier. A second operation mode in which the servo motor is rotated at high speed by applying a constant command voltage to the Since the system is constructed so that the tool support is moved backward by cutting off the sending of the Even if the speed is increased, it is possible to prevent the processing of the numerical control device main body from being delayed.

Therefore, it is possible to significantly increase the rotational speed of the workpiece and complete machining in a short time, which has the advantage of greatly improving machining efficiency.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the lower cylinder of the video tape recorder, Fig. 2 is a developed view showing the shape of the guide surface S in Fig. 1, Fig. 3 is an overall configuration diagram to clarify the present invention, and Fig. 4 5 is a block diagram showing the configuration of the control circuit, FIG. 6 is a diagram showing the contents of the profile data area PDA in FIG. 5, and FIG.
FIG. 8 is a block diagram showing the configuration of the drive units DUZ and DUX in FIG. 5. FIG. 9 to 12 are block diagrams showing the configuration of the drive unit DUO in FIG. 5.
13 is a diagram showing the positional relationship between the tool T and the workpiece W at the machining start position, and FIG. 14 is a flowchart showing the position of the tool T and the information supplied to the calculator 44 when the tool T is retracted. FIG. 3 is a diagram showing the relationship between the magnitudes of command voltages. 11... Headstock, 12... Cutting table, 13... Tool support, 18, 25, 26... Servo motor,
19...Absolute position detector, 20...Main shaft, 21...
...Chuck, 22...Spindle motor, 23...Displacement detector, 30...Numerical controller main body, 31...Memory, 33, 34, 35...Pulse generation circuit, 4
0... Deviation counter, 41... DA converter, 45
... Servo amplifier, 46 ... DA converter, AG1,
AG2...Analog gate, FF1, FF2...Flip-flop, T...Tool, W...Workpiece.

Claims (1)

[Claims] 1. A first operation of moving a tool in a specific direction from a fixed position reference point in synchronization with the rotation of the cylindrical workpiece while the rotating cylindrical workpiece is within a fixed angular phase range; In the tool feed control device for a turning machine, the tool feed control device for a turning machine is configured to perform a second operation of rapidly retracting the tool to the position reference point while the tool is out of the constant angular phase range. angular phase detection means for detecting that the angular phase has reached the start and end points of the range; position detection means for detecting that the tool is located at the position reference point; and a position detection means that is linked with the tool feeding mechanism. A servo motor, a signal sending means for sending a control signal to the servo motor in response to a numerical command pulse, and a detection that the workpiece has reached the starting point of the angle range by the angle detecting means. interrupting means for enabling said signal emitting means in response to and interrupting a control signal of said signal emitting means in response to detecting that said workpiece has reached the end of said angular range; pulse distributing means for distributing numerical command pulses to the signal sending means according to numerical data while within the phase range; and pulse distributing means for distributing numerical command pulses to the signal sending means in accordance with numerical data while the servo is in the phase range; 1. A tool feed control device for a turning machine, comprising control signal generating means for generating a control signal for rotating a motor at high speed.