JPH0120021B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for controlling a spindle fixed position stop in a numerically controlled machine tool, and particularly to a device for confirming the spindle fixed position stop operation independently from numerical control operations or machine operations such as tool exchange. This invention relates to a main spindle fixed position stop control device that allows

A machine tool with an automatic tool exchange function performs machining while automatically exchanging various tools, and the tool exchange operation is performed as follows.

That is, first, rotate the magazine that holds the tool so that the empty tool gripping part is positioned directly above the spindle mechanism, then project the spindle mechanism with the old tool to be replaced forward, and then open the magazine. The old tool is lowered onto the spindle mechanism, the old tool is fitted and held in the tool gripping portion, the spindle mechanism is retracted, and the old tool is removed from the spindle. Thereafter, the magazine is rotated to position a desired new tool in front of the spindle, the spindle mechanism is projected forward to mount the new tool on the spindle, and the magazine is then pulled upwards, thereby completing the tool exchange. In the automatic tool changing mechanism as described above, in order to smoothly fit the spindle and the fitting portion of the tool, a predetermined portion of the spindle, such as a key, must be stopped at an accurate position. This is because a key is attached to the spindle, and a key groove is formed on the tool to fit the key.If the spindle is not positioned and stopped so that the key correctly faces the key groove, the spindle will not move. This is because the tool cannot be fitted smoothly. Therefore, the positioning accuracy of the main shaft is required to be as high as ±0.1° to ±0.2° in terms of rotation angle.

By the way, in the conventional automatic tool change mechanism, in order to smoothly fit the main shaft and the fitting part of the tool,
A photoelectric detector and limit switch mechanism were installed to detect the key position of the spindle, and a mechanical brake was activated based on the detection signals from these mechanisms to stop the spindle at a predetermined stop position.

However, since the above-mentioned conventional devices use mechanical stopping mechanisms such as pins and brakes, the stopping mechanisms such as brake shoes and pins wear out over long periods of use, making it difficult to stop the spindle at a predetermined position. Therefore, automatic tool exchange could not be performed smoothly.

Therefore, during automatic tool exchange, there is a need for a main spindle fixed position stop control device that stops the main spindle at a predetermined position with high accuracy purely electrically without requiring a mechanical stopping mechanism such as a mechanical pin or brake.

For this reason, the applicant of the present application has proposed a main spindle fixed position stopping device that can accurately stop the main spindle at a fixed position purely electrically.

By the way, in order to confirm whether or not the spindle fixed position stop control is executed correctly in the spindle fixed position stop device that has already been proposed, an NC
For example, it was necessary to input the M function command "M19" or "M06", which instructs automatic tool change, through the high-speed electrical panel. This makes the operation troublesome, and furthermore, when the M function command "M19" or "M06" is input, the tool change is executed after the spindle has stopped at the fixed position. It was not possible to independently and easily check whether the system was operating correctly.
Furthermore, in the operation test of conventional fixed position stop control, it is necessary that the NC or power control board is operating accurately, and if a malfunction occurs, it is necessary to check whether the NC, power control board, or spindle fixed position stop device is operating correctly. The problem was that it was difficult to determine whether a failure had occurred.

Therefore, the present invention improves the spindle fixed position stop control operation.
It is an object of the present invention to provide a spindle fixed position stop control device that can independently perform a confirmation test of the spindle fixed position stop operation independently of numerical control operation control by NC and mechanical operation control by a powerful electric panel.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 1 is a circuit block diagram illustrating the outline of the spindle fixed position stop control circuit according to the present invention, Fig. 2 is a waveform diagram of each part of the same, and Figs. 3 and 4 are explanations explaining the operation and configuration of the magnetic sensor. It is a diagram.

In the figure, 1 is a speed command circuit which outputs a speed command CV. 2 is a fixed position stop command circuit that outputs a fixed position stop (orientation) command ORCM; 3 is a speed control circuit, which includes an adder 3a and a phase compensation circuit 3b.
, a voltage/phase converter 3c, and a thyristor circuit 3d. During speed control, the adder 3a calculates the difference voltage (speed deviation) between the command speed CV and the actual speed AV.
Outputs the position deviation signal RPD during position control.
Outputs the difference voltage between the actual speed AV and the actual speed AV. The phase compensation circuit 3b advances or delays the phase of the adder output voltage to compensate for the phase. The voltage/phase converter 3c controls the firing angle of each thyristor constituting the thyristor circuit 3d according to the output voltage of the phase compensation circuit 3b. The thyristor circuit 3d controls the firing angle of each thyristor and changes the voltage applied to the DC motor.
The rotational speed of the DC motor is controlled. 4 is a DC motor, 5 is a tachometer that generates a voltage according to the rotational speed of the DC motor 4, 6 is a main shaft mechanism, 7 is a main shaft, 8 is a tool, 9 is a main shaft 7 that controls the rotation of the DC motor 4
It is a gear (or a timing belt may be used) that transmits the signal. Reference numeral 10 denotes a magnetic sensor, which, as shown in FIG. 3, is composed of a magnetic body 10a, a sensing section 10b, and an electric circuit 10c.

The position detection sensor will be described in detail below. Third
Figures A and B are a front view and a plan view when the magnetic body 10a is attached to the main shaft 7. When it is desired to stop a predetermined portion of the main shaft at a fixed position, the magnet 10a is installed on the main shaft at the same rotation angle as the predetermined portion, and the third
As shown in Figure C, rubber magnets 10a'', 10a each having a triangular cross section are mounted inside the case 10a' so that the strength of magnetization changes from the S pole to the N pole in the direction of rotation (in the direction of the arrow).On the other hand, The sense part 10b is attached to a machine fixing part so as to face the magnetic body 10a, and as shown in FIG. 3C, three saturable reactors SRA1 to SRA3 are arranged in parallel in the rotational direction inside the case 10b'. .Each saturable reactor
SRA1 to SRA3 have coils L ₁ and L ₂ in the core CR.
It is wound as shown in Figure D. One more core
The coils L ₁ and L ₂ wound around CR are wound with opposite polarity to each other, and a high frequency signal is input to the common terminal TA of each coil, and the high frequency signal is inputted from the terminals TB and TC depending on the position of the magnet 10a. A signal is output. FIG. 3E shows the output voltage from the sense section 10b with the horizontal axis as the time axis. As shown in FIG. 3C, when the magnetizing body 10a acts on each saturable reactor SRA in a positional relationship in which it moves in the direction of the arrow in the figure with respect to the sense unit 10b due to the rotation of the main shaft 7, each reactor In the electric circuit 10c connected to the SRA, voltage waveforms DV ₁ , DV ₂ , and DV ₃ are formed. In other words, when the center line of the magnetizing element 10a matches the center line of each saturable reactor SRA, zero volts are output from between the terminals TB and TC, and when they are near both sides, positive and negative voltages are output. A voltage waveform that entirely crosses the zero level is output. Note that the voltage waveform ASV is the sum of the voltages obtained by shifting the phases of the detection voltages DV ₁ and DV ₃ by 180°. FIG. 3F is a detailed diagram of a sense circuit provided corresponding to one saturable reactor SRA1. Each sense circuit is provided in the electric circuit 10C, and includes a pulse oscillator OSC that generates a 100KHz high frequency pulse signal HFP,
It consists of an isolation transformer ITR, half-wave rectifiers HWR ₁ and HWR ₂ , and a saturable reactor is connected via the isolation transformer ITR by a high-frequency pulse signal HFP.
SRA1 is excited, which causes an external magnetic field Hext whose strength changes depending on the position of the magnet 10a.
The output voltage DV ₁ (Fig. 3 E) approximately proportional to terminal a
- Output from between b.

Next, the effect that the voltage waveform DV ₁ shown in Figure 3E is output from terminals a and b is expressed by the reactor on the right.
This will be explained with reference to FIG. 4, focusing on SRA1.
When the magnetizing body 10a is away from the saturable reactor SRA1 and the external magnetic field to the saturable reactor SRA1 is zero, the high frequency pulse signal HFP
operates around the zero of the B-H curve of the saturable reactor shown in FIG. 4A. For this reason, the coil L ₁ ,
The number of magnetic fluxes interlinking with L ₂ is equal, and the terminals TB,
The voltage output from the TC has a waveform with equal amplitude and a 180° phase shift. Incidentally, since these voltages are rectified by the half-wave rectifier circuits HWR ₁ and HWR _2, the potentials of terminals a and b are equal, and the voltage between a and b becomes zero.

Next, the magnetizing body 10a is the saturable reactor SRA
When approaching 1, the external magnetic field generated by the magnetizing body Hext
begins to act on the saturable reactor. Now, if the magnetic field caused by the high-frequency pulse signal HFP is hl, the magnetic flux corresponding to (hl-Hext) interlinks with the coil _L1 as shown in Figure 4C, and the magnetic flux corresponding to (hl+Hext) exists in the coil _L2. are interlinked. If we explain this using a B-H curve, a high-frequency pulse signal will be generated for coil _L1 .
HFP operates mainly on -Hext (Figure 4C),
Also, for coil L ₂ , high frequency pulse signal HFP
operates mainly on +Hext (Fig. 4D). Therefore, the magnetic flux in the negative direction interlinking with the coil _L1 is saturated and its amount of change is small, and the magnetic flux in the negative direction interlinking with the coil _L2 is not saturated and its amount of change is large. If we consider that the induced voltage e is e=-N(dφ/dt) (where N is the number of windings), the potential of terminal b will be greater than the potential of terminal a, and the voltage between a and b will be A potential difference is generated. Thereafter, if the magnetizing body 10a continues to rotate, the potential difference changes as shown by DV ₁ in FIG. 3E. The above is an overview of the configuration and operation of the position detection sensor 10.

Returning to Fig. 1, 11 is a fixed position stop circuit, and the position deviation signal RPD has a voltage value according to the position deviation.
, orientation completion signal ORDEN, and speed attainment signal that becomes “1” when the spindle rotation speed reaches a predetermined speed (referred to as orientation speed).
VZR (when the orientation speed is reached)
The speed attainment signal VZR becomes "1" when the fixed position stop command ORCM is commanded from the fixed position deviation signal generation circuit 11a, which outputs VZR = "1", and the fixed position stop command circuit 2. Loop switching circuit 1 that switches the loop switching switch 12 by
1b. Note that the operation mode in which a series of operations is performed from when the orientation command ORCM is issued, when the loop changeover switch 12 is switched to the position control loop side, until the spindle stops at a predetermined position is called a fixed position stop mode. Although the fixed position deviation signal generating circuit 11a will be explained in detail later, the general operation of generating the position deviation signal RPD will be briefly explained in accordance with the waveform diagrams shown in FIGS. 2A and 2B.

a detection voltage DV ₂ (this is used as a fine position deviation signal near the local position value) corresponding to a saturable reactor SRA ₂ (FIG. 3C) disposed at the center of the magnetic sensor 10 for position detection; Detection voltage
It is obtained by adding the voltage obtained by shifting the phase of DV ₁ and DV ₃ by 180°, and the main axis is in the area near the fixed position.
Fixed position proximity signal ASV indicating arrival at NCP
are respectively input to the fixed position error signal generation circuit 11a. On the other hand, the measured speed signal AV is input from the tachometer 5, and this measured speed signal AV is integrated by an integral circuit (not shown) in the fixed position error signal generation circuit 11a, and its integrated output (the amount of rotation of the main shaft is equal) is subtracted from the initial setting voltage ISV and converted into a coarse position deviation signal CPD. In addition, the voltage value Vi of this initial setting voltage ISV is one rotation (360°)
is set to be equal to the position deviation voltage corresponding to . Further, the fixed position deviation signal generation circuit 11a
Internally, a bias signal BIS with an amplitude equal to the peak value of the fine position deviation signal DV ₂ is also created.

Here, the fixed position stop command ORCM is generated from the fixed position stop command circuit 2, and when the command speed CV becomes zero, the rotational speed of the spindle decreases until sometime (time
(at t ₁ ) the orientation speed is reached (velocity attainment signal VZR="1"). When the rotational speed of the spindle reaches the orientation speed, the fixed position deviation signal generation circuit 11a outputs the initial set voltage from the time the speed signal VZR becomes "1" until the first fixed position arrival time _t2 .
Output ISV. Thereafter, the magnet generating body 10a (predetermined part of the main shaft) continues to approach the fixed position for the second time, and remains in the coarse position until it comes close to the neighboring area NCP (-θ ₁ to +θ ₁ ) (until it reaches -θ ₂ ) It outputs the deviation signal CPD, and also outputs the bias signal BIS until it reaches the nearby area NCP, and further outputs the fine position deviation signal DV ₂ after reaching the nearby area NCP, as shown in Figure 2A. Outputs position deviation signal RPD. still,
Bias signal waveform BIS becomes RPD as θ ₂ = θ ₁
may not exist.

The operation of the main spindle fixed position stop control circuit shown in FIG. 1 will be explained below with reference to FIG. 2B.

When the main shaft is rotating, the loop changeover switch 12 is switched to the a side, forming a speed control loop. That is, the command speed CV from the speed command circuit 1 and the actual speed AV from the tachometer 5 are input to the adder 3a, and a speed deviation voltage is output from the adder 3a. The firing angle of each thyristor constituting the thyristor circuit 3d is controlled by the voltage/phase converter 3c in accordance with this speed deviation voltage, and the voltage applied to the DC motor 4 is increased or decreased. As a result, the actual speed AV of the DC motor 4 increases or decreases to match the command speed CV. Thereafter, the speed is controlled so that the speed deviation becomes zero, and the main shaft rotates with a constant speed deviation.

When the cutting work is completed in the above state, the constant position stop command ORCM is input from the constant position stop command circuit 2 to the loop switching circuit 11b at time _t0 under the control of the numerical control device, and at the same time this constant position stop command ORCM is used as the speed command. It is also input to circuit 1, and the command speed CV becomes zero, and the entire circuit enters the fixed position stop mode. As a result, the actual speed AV decreases at time t ₁
The orientation speed becomes Sc. When the actual speed AV becomes the orientation speed Sc, the speed attainment signal VZR is output from the fixed position deviation signal generation circuit 11a.
Generated internally, this speed attainment signal VZR causes the loop switching circuit 11b to switch the loop switching switch 12 to the b side and shift from speed control to position control. Further, in response to the speed attainment signal VZR, the fixed position deviation signal generation circuit 11a first outputs the initial setting voltage ISV having the voltage value Vi. As a result, the actual measured degree signal AV of the main axis maintains Vi. and magnetic sensor 10
The magnetizing body 10a (Fig. 3) continues to rotate, and the first
When the constant position is reached (time t ₂ ), the constant position deviation signal generation circuit 11a thereafter outputs the coarse position deviation signal CPD. The main shaft continues to rotate,
When the magnet 10a approaches the vicinity area NCP of the fixed position (time t ₃ ), the fixed position deviation signal generator 11a outputs the bias signal BIS, and when it reaches the vicinity area (t ₄ ), the fine position deviation signal is then output. DV ₂ is output, and when the fine position deviation signal DV ₂ becomes zero, that is, when the magnetizing body 10a (predetermined part of the main shaft) correctly faces the saturable reactor SRA in the middle, it stops.
Spindle fixed position stop control ends.

FIG. 5 is a detailed circuit diagram of the fixed position deviation signal generating circuit 11a, and FIG. 6 is a time chart thereof.
Note that the same parts as in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

In the figure, 101 is a coarse position error signal generation circuit that generates the initial setting voltage ISV and bias signal BIS, integrates the actual speed AV, and subtracts the integrated output of the actual speed AV from the initial setting voltage ISV.
That is, the changeover switch ASW is switched to the +15V or -15V side depending on the direction of rotation of the main shaft. If it is rotating forward, set it to the -15V side. This voltage is divided by resistors r ₁ and r ₂ and connected to amplifier AMP, resistor r ₄ and switch.
The capacitor C is charged via SW ₉ , and this charging voltage becomes the voltage value Vi of the initial setting voltage ISV. After switch SW ₉ is turned off, the actual speed AV is set to switch SW ₈ .
Or if it is input via SW ₇ , the voltage value of the actual speed AV is smaller than Vi, so the capacitor C is discharged with the time constant RC, and the amplifier AMP ₂ (this amplifier AMP ₂
A coarse position deviation signal CPD obtained by subtracting the integral output of the actual speed AV from the initial setting voltage ISV is output to the output terminal of the integrator circuit formed by R and C. After the voltage of the coarse position deviation signal CPD becomes zero, if the switches SW ₉ and SW ₁₀ are turned on, the coarse position deviation signal generation circuit 101 becomes an amplifier, and the output terminal of the amplifier AMP ₂ receives a bias signal BIS of a predetermined level. is output. In other words, depending on the on/off combination and timing of switches SW ₇ to _{SW 10} , the coarse position deviation signal generation circuit 101 first outputs the initial setting voltage ISV, then the coarse position deviation signal CPD, and finally the bias signal BIS. Output.

102 and 103 are switching circuits that change the gain depending on the gear ratio, and when the gear between the main shaft 7 of the DC motor 4 is low (Low; reduction ratio is large), the gain of the position control loop is increased and the gear is high (High; reduction ratio). (small), the gain is made smaller than when it is low. In other words, when the reduction ratio is large, the switch _SW7 ,
Turn on SW ₂ to increase the gain, and when the reduction ratio is small, turn on switches SW ₈ and SW ₃ to decrease the gain. This eliminates hunting and overshooting of the spindle during fixed position stop control, and
Regardless of whether the reduction ratio is large or small, the time required to complete a fixed position stop can be shortened. A known absolute value circuit 104 converts the output of the coarse position deviation signal generation circuit 101 into an absolute value. A comparator 105 detects whether the coarse position deviation signal CPD has fallen below a predetermined level, and detects whether a predetermined portion of the main shaft (magnetic element 10a) is in the region near the home position (the region from −θ ₂ to +θ ₂ in FIG. 2A). )
Outputs a near signal NRPS indicating that the vehicle is approaching. This near signal NRPS causes switch SW ₉ ,
SW ₁₀ is turned on. A gain adjustment circuit 106 adjusts the gain according to the gap between the magnet 10a and the sensing section 10b, and outputs a desired slope detection voltage (fine position deviation voltage) _DV2 . Reference numeral 107 denotes a slicing circuit that slices the home position vicinity signal ASV at a predetermined level and outputs a vicinity area arrival signal LS indicating that the home position vicinity signal ASV has reached the home position vicinity area NCP (FIG. 2A). switch
Turn off SW ₅ and SW ₆ , and turn on switch SW ₄ .
As a result, the fine position deviation signal DV ₂ is output as a position deviation signal. 108 is a forward/reverse switching circuit; when performing fixed position stop control by forward rotation, switch SW ₆ is turned on and the output of the absolute value circuit 104 is output as is; when performing it by reverse rotation, switch SW ₅ is turned on; The output of the absolute value circuit 104 is inverted by an amplifier 108a and output. 109
is an in-position signal generator, which is composed of a comparator, monitors the fine position deviation signal DV ₂ , generates an in-position signal INPOS when the spindle enters the fixed position stop range, and generates an orientation completion signal, which will be described later. It is input to circuit 114. Both 10 and 111 monitor the fine position deviation signal DV ₂ with a comparator, and the main shaft is approaching the home position while rotating in reverse (NEG = "1") or in the forward direction (POS = "1"). It outputs the signals NEG and POS. And this
Depending on whether NEG or POS is “1”,
A speed attainment signal from the speed detection circuit 113, which will be described later.
VZR is output, and the switch is activated by the nearby area arrival signal LS output from the slice circuit 107.
One of SW ₅ and SW ₆ is controlled to be on or off. 11
2 is a waveform synthesis circuit, and switches SW ₄ , SW ₅ or
Fine position deviation signal by turning SW ₆ on/off
Outputs either DV ₂ or coarse position deviation signal CPD. 113 receives the actual speed voltage AV, and when the actual speed voltage AV becomes zero, it outputs a speed zero signal SZR.
, and a speed detection circuit which outputs a speed attainment signal VZR when the orientation speed is reached. Reference numeral 114 denotes an orientation completion signal generation circuit, into which the in-position INPOS, the zero speed signal SZR, and the fixed position stop command ORCM (actually, the signal _S4 that turns on the switch _SW4 is used) are input. Performs an AND operation on each signal. In other words, INPOS, SZR, and S ₄ are all “1”
At this time, the orientation completion signal ORDEN is output.

In summary, if the orientation command ORCM becomes "1" at time t ₀ , the command speed CV becomes zero volts, and therefore the actual speed AV decreases and the time
At t ₁ , AV reaches the orientation speed and the speed attainment signal VZR becomes "1". speed reached signal
When VZR becomes “1”, loop changeover switch 1
Contact point 2 switches to the b side, and one of switches SW ₂ and SW ₃ turns on depending on whether the gear is low or high, and the switch also turns on depending on whether the main shaft rotates forward or reverse.
One of SW ₅ and SW ₆ turns on. As a result, a position control loop is formed, and the initial setting voltage ISV is output from the loop changeover switch 12.
SW ₉ is on, SW ₇ , SW ₈ , and SW ₁₀ are off).

When the DC motor first reaches the fixed position (nearby area arrival signal LS = “1” in-position signal
INPOS="1"), at time _t2 , switch SW ₉ is turned off, and the switch is turned off according to the low/high gear.
Turn on either SW ₇ or SW ₈ . As a result, the coarse deviation signal is output from the loop changeover switch 12.
CPD is output.

After that, both the actual speed AV and the positional deviation decrease, and when the main axis approaches the area near the fixed position (time t ₃ ), the near signal NRPS (="1") is output from the comparator 105, and the switch SW ₉ and the switch Both SW10 are turned on. As a result, the loop changeover switch 12
A bias signal BIS of a predetermined level is outputted from.

The main shaft continues to rotate at low speed, and when it reaches the area near the fixed position (time t ₄ ), the near area arrival signal LS = "1"
Then, switches SW ₅ and SW ₆ turned off,
Switch SW ₄ is turned on, and fine position deviation signal DV ₂ is output from output terminal OUT. Then, when the magnetizing body 10a (predetermined portion of the spindle) enters the fixed position stop range, an in-position signal INPOS is generated, and then, when the actual speed of the spindle becomes zero, the zero speed signal SZR becomes "1". This completes the main spindle regular position stop control, and the regular position stop completion signal ORDEN is output from the regular position stop completion signal generation circuit 114. The fixed position stop mode then ends. 7th
This figure is an explanatory diagram illustrating an outline of an on/off signal generation circuit for switches SW ₁ to _{SW 10} of the position deviation signal generation circuit 11a shown in FIG.

In the figure, 201 is an orientation test circuit, which executes orientation regardless of the signal from the NC or high-power circuit. That is,
The spindle fixed position stop circuit 11 (FIG. 1) is put into test mode and orientation is executed. Note that this circuit 201 has a function of preventing the orientation completion signal generation circuit 203 from sending out the orientation completion signal ORDEN to the machine side when orientation is completed.

When a tool needs to be replaced while a workpiece is being processed by a machine tool, the machine tool is switched to a fixed position stop mode and the fixed position stop operation as described above is executed. When this operation is completed, the next step, ie, the operation of mounting the next tool on the spindle is automatically performed according to the program. This transition to the next operation is normally performed after an orientation completion signal is generated. Therefore, unless the orientation completion signal ORDEN is output, the machine will not perform automatic tool exchange.

202 is a sequence circuit; 203 is an orientation completion signal generation circuit; an orientation test circuit 201; a sequence circuit 20;
2. Orientation completion signal generation circuit 203
together constitute substantially the same circuit as the orientation completion signal generation circuit 114 shown in FIG.
Furthermore, these circuits have a circuit that operates in a test mode, that is, a mode in which only the spindle fixed position stop control device is operated in a fixed position stop mode and that the orientation completion signal ORDEN cannot be generated during operation in a mode in which the device is tested. .

The sequence circuit 202 consists of a large number of logic gates, and has a near signal NRPS, a nearby area arrival signal LS,
A switch signal that inputs the clutch switching signal CTH, forward rotation signal POS, one rotation signal LSOF, speed attainment signal VZR, etc., and turns on/off the switches SW ₁ to _{SW 10} of the fixed position error signal generation circuit 11a shown in FIG. *S ₁ to *S ₁₀ are generated. In addition, in these switch signals, when (i = 1, 2, ... 10) is "0", the switch SWi is turned on, and when *Si is "1", the switch SWi is turned on.
SWi is turned off. _R1 to _R7 are resistors, and _C1 to _C2 are capacitors. D ₁ ~ _{D 5} are diodes, TD is a light emitting diode indicating that it is under test, ORD is a light emitting diode indicating that orientation is complete, NOT ₁
~NOT ₄ is NOT gate, NAND ₁ ~NAND ₁₀ is NAND gate, NOR ₁ ~ _{NOR 3} is Noah gate, Tr
is a transistor. SB is a shot bar provided in the orientation test circuit 201 and puts the fixed position stop circuit 11 of the spindle into test mode, and is a printed board provided with the fixed position stop circuit 11.
By short-circuiting shunt pins SP ₁ and SP ₂ on PT (FIG. 8), the fixed position stop circuit 11 of the spindle can be forced into the test mode. In addition,
By shorting the shunt pins SP ₁ and SP ₂ with the shunt bar SB, the light emitting diode TD emits light to indicate that the device is in test mode.
In addition, the output state of the NOR gate NOR ₂ becomes the same state as when the spindle fixed position stop command ORCM is commanded (the output of NOR ₂ is "1"). TSW is a test switch provided in the orientation test circuit 201.
When the test switch (TSW)
When the switch continues to be turned on, the main shaft continues to rotate at a predetermined speed (orientation speed), and when the switch is turned off, the orientation operation is started. That is, the test switch TSW serves as a switch means for controlling the start of operation of a switching means including a shot bar for forcibly switching to the fixed position stop mode, ignoring commands from the numerical control device. This turns on the test switch TSW and the NAND gate
The output of NAND ₂ becomes "1" and the output of NOR gate NOR ₃ in the sequence circuit 202 becomes "0". Therefore, the output signal *ORSH of NAND gate NAND ₃ to shift to the orientation operation becomes "0" (VZR= This is because the state of the latch circuit LACH made up of the NAND gate NAND ₄ and the NOR gate NOR ₁ does not invert even if the signal becomes "1" and LSOF="1". Note that the signal *INCL is an enable signal, and when this signal is "1", normal spindle fixed position stop control, which is not in test mode, can be performed.

Next, the operation shown in FIG. 7 will be explained with reference to FIG. In addition, in Fig. 7, the loop changeover switch 1 is activated by the fixed position stop command ORCM and the speed attainment signal VZR.
The explanation will be given assuming that the loop changeover switch 12 immediately switches to the b side and the ISV is output from the loop changeover switch 12.

During normal spindle fixed position stop control, first, a spindle fixed position stop command *ORCM (="0") is output from the main spindle fixed position stop command circuit 2 (FIG. 1). As a result, the rotational speed of the main shaft reaches a predetermined value through the above-described operation, and the speed attainment signal VZR is output. By outputting this signal, the switch signal *S ₁
becomes "1" and the switch 12 (Fig. 5) changes to the b side, and depending on the high/low gear (gear low *CTH = 0, gear high *CTH
= "1"), one of the switch signals *S ₂ and *S ₃ becomes "0" and one of the switches SW ₂ and SW ₃ (FIG. 5) is turned on.

Since the output of NOR gate NOR ₃ is “0” until the spindle fixed position stop command ORCM is input, the NAND gate of the latch circuit LACH is initially
The output of NAND ₄ is "0", so the switch signal *S ₉ becomes "0" and the switch SW ₉
(Fig. 5) is on. In addition, Switch SW ₅ ,
One side of SW ₆ (Figure 5) is also on.

Therefore, in this state, if the spindle fixed position stop command ORCM is input as described above (*ORCM
= "0"), the initial value setting voltage ISV (constant voltage Vi), which is the output of the integrating circuit in Fig. 5, is first sent to switch SW ₅ or switch SW ₆ as a position deviation signal → switch
Output via SW ₂ or switch SW ₃ .

Then, when the spindle speed reaches the orientation speed (VZR="1") and the one-rotation signal LSOF (created from the in-position signal shown in Figure 6) is generated, the latched state of the latch circuit LACH is reversed. Then, the switch signal *S ₉ becomes "1", switch SW ₉ is turned off, and one of the switch signals *S ₇ and *S ₈ becomes "0" according to the low/high gear, which causes the switch SW 9 to turn off. ₇ and SW ₈ (Fig. 5) are turned on. The one-rotation signal LSOF is created by capturing the first rising point of the in-position signal that occurs every one rotation of the spindle, as shown in FIG. As a result, a coarse position deviation signal is generated from the coarse position deviation signal generation circuit 101 shown in FIG.
CPD is output and this coarse position deviation signal
CPD is output via switch SW ₅ or SW ₆ → switch SW ₂ or switch SW ₃ .

Thereafter, as explained with reference to FIGS. 5 and 6, the bias signal BIS and fine position deviation signal DV ₂ are output, and finally, the imposition signals INPOS,
When the speed zero signal SZR becomes “1”, the NAND gate
NAND ₁₀ output is “0”, NAND gate NAND ₉
The output of the NOT gate becomes "1", the output of NOT gate NOT ₂ becomes 0, the light emitting diode ORD emits light to indicate the completion of orientation, and the transistor
Since the Tr is turned on, the orientation completion signal *ORDEN is sent to the NC or machine tool indicator, and tool changes are executed continuously.

On the other hand, when testing whether the main shaft fixed position stop circuit 11 (FIG. 1) operates correctly, first short-circuit pins SP ₁ and SP ₂ using the shot bar SB. As a result, the light emitting diode TD emits light to indicate that the test is in progress, and the NOR gate
The same state occurs when the output of NOR ₂ becomes "1". When the test switch TSW is turned on in this state, the output of the NAND gate NAND ₂ becomes "1" and the output of the NOR gate NOR ₃ becomes "0". Therefore, the latch state of the latch circuit LACH remains constant without depending on other signals (the output of the NAND gate NAND ₄ is "1"), and the switch signal *
_S9 remains "0" as long as the test switch TSW is turned on. As a result, switch SW ₉ remains on, and the initial setting voltage ISV is set to switch SW ₅ or SW _6.
→Since it is output via switch SW ₂ or SW ₃ , the spindle continues to rotate at the orientation speed, that is, the command speed is ISV. In addition, the switch
The on/off control of SW ₂ and SW ₃ is performed in exactly the same way as in the fixed position stop mode.

When the spindle is rotating at the orientation speed, if you release the pressure on the test switch TSW and turn it off, the output of the NAND gate NAND ₂ becomes "1" and the state of the latch circuit LACH can be changed. . Then, the main shaft is rotating at the orientation speed (VZR="1") and the one-rotation signal LSOF has been generated (LSOF=
“1”) causes the output of NAND gate NAND ₃ to become “0”, switch signal *S9 becomes “1”, and *S ₇
Or, one of * _S8 becomes "0", switch _SW9 is turned off, and switch _SW7 or _SW8 is turned on instead.

After that, the spindle is controlled to stop at a fixed position in the same way as in the fixed position stop mode, and when it reaches the fixed position (in-position signal INPOS = "1", zero speed signal SZR)
="1"), the light emitting diode ORD emits light indicating completion of orientation. However, even after the orientation is completed, the operation of the transistor Tr is suppressed because the shoot bar SB forcibly grounds the base side of the transistor Tr, and the transistor Tr is not turned on. Therefore, the orientation completion signal is not turned on.
ORDEN is not sent to NC or machine. In other words, the shoot bar SB, which was one of the means for forcibly switching to the fixed position stop mode ignoring commands from the numerical control device, was replaced by the orientation completion signal generation circuit that generates the orientation completion signal ORDEN. It also serves as a means to inhibit movement. In addition, in the above embodiment, the stop of the main shaft at a fixed position is indicated by light emission from the light emitting diode ORD.
Since it is possible to confirm that the spindle is stopped at a fixed position by visually checking the spindle, and in the present invention, it is not necessary to output the orientation completion signal ORDEN to the NC when executing the test mode, this light emitting diode is It's not required.

As described above, the present invention is configured so that the orientation completion signal is not output at the final point of the orientation test mode, and the confirmation test of the spindle fixed position stop operation is performed independently of the numerical control operation and the mechanical operation. As a result, tests can be easily performed, and even if a malfunction occurs, the cause can be easily determined, thereby improving the operability of the spindle fixed position stop control device. .

Further, a switching means and a switch means are provided in an orientation test circuit for forcibly switching the spindle fixed position stop control device to the fixed position stop mode, and the operating point of the switching means can be freely set by the switch means. I configured it so that you can select it.
The operator can start the orientation test mode from a desired time, and in this respect as well, the operability of the main spindle fixed position stop control device can be improved.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram illustrating the outline of the spindle fixed position stop control circuit according to the present invention, FIG. 2 is a waveform diagram of each part of the same, and FIGS. 3 and 4 show the operation of the shaft sensor.
An explanatory diagram explaining the configuration, FIG. 5 is a detailed circuit diagram of the position error signal generation circuit, FIG. 6 is a time chart of the same, and FIG. 7 is a schematic diagram of the on/off signal generation circuit of the switch shown in FIG. 5. 8 are explanatory diagrams of the printed board showing the positions of the shot bars and the like. 1...Speed command circuit, 2...Fixed position stop command circuit, 3...Speed control circuit, 4...DC motor, 5
... Rotation speed meter, 7 ... Main shaft, 10 ... Magnetic sensor, 11 ... Fixed position stop circuit, 201 ... Orientation test circuit, 202 ... Sequence circuit, 203 ... Orientation completion signal generation circuit , TSW...Test switch, SB...Shot bar.

Claims (1)

[Claims] 1 The main spindle of a machine tool, the main spindle motor that rotationally drives the main spindle, the speed control loop that rotates the main spindle motor at a command speed, the current position of a predetermined part of the main spindle, and the fixed position at which the predetermined part of the main spindle should stop. a position control loop that drives the spindle so that the position deviation becomes zero and stops a predetermined portion of the spindle at a fixed position; a switching means that switches between the speed control loop and the position control loop according to a command from a numerical control device; In a spindle fixed position stop control device that has a signal generation circuit that outputs an orientation completion signal to a numerical control device to prompt a tool change operation when stopped in a fixed position, the control mode of the spindle motor is controlled by commands from the numerical control device. An orientation test circuit having a switching means for forcibly switching to a fixed position stop mode without regard to the switching means, and a switching means for controlling the start of operation of the switching means; a sequence circuit for sequentially controlling a means for generating a signal that operates in response to a signal and causes the spindle motor to rotate to a predetermined stop position during operation in the forcibly switched fixed position stop mode; and means for suppressing the operation of the signal generation circuit that generates an orientation completion signal for prompting a tool change operation when the spindle stops at a predetermined position in the fixed position stop mode switched to. Spindle fixed position stop control device.