JPS5853973B2 - Deceleration control device for table rotation axis in numerically controlled hogo board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention separately electrically drives a cutting hob shaft and a table rotation shaft, and adjusts the rotation speed ratio and mutual phase relationship using electrical auxiliary means such as a pulse generator. This invention relates to a numerically controlled hobbing machine that performs deceleration control.

FIG. 1 is a control block diagram of a conventional numerically controlled hobbing machine, and 1 is a command value register that stores various input data from an NC tape.

2 is a unit movement amount determination circuit which inputs the data stored in the command value register and determines the unit movement amount ΔC of the table rotation axis; 3 stores the value determined by the unit movement amount determination circuit. This is a register for

A pulse generator 4 is coupled to the cutting hob shaft and controls the cutting hob shaft to maintain the rotation speed ratio and phase relationship between the cutting hob shaft and the table rotation shaft.

Reference numeral 5 designates an AND gate that passes the unit movement amount ΔC stored in the register 3 each time a pulse is output from the pulse generator.

6 is the unit movement amount △C that has passed through the AND gate
This is an arithmetic unit that inputs and adds the values fed back from the table rotation axis function generation circuit 7, which will be described later.

Reference numeral 7 denotes a table rotation axis function generation circuit for inputting the value output from the arithmetic unit and generating a function for driving the table rotation axis.

In such a numerically controlled hobbing machine, if the machine is stopped due to a power outage or gear dimension measurement, the phase relationship between the cutting hob axis and the table rotation axis becomes irrelevant, so cutting must be continued again. The drawback was that it was not possible.

Also, when correcting the phase difference by decelerating the table rotation axis, if the correction amount is extremely close to zero, the table rotation axis rotating at a unit movement amount △C will instantly drop to a value close to zero. This resulted in deceleration, and deceleration control was difficult due to various factors such as inertia.

The purpose of the present invention is to restore the mutual phase relationship between the cutting hob axis and the table rotation axis, which have become unrelated after the power is cut off or the machine is stopped. When the pitch is within the pitch, the unit movement amount △C is replaced by the first corrected unit movement amount △C' to decelerate and phase matching is performed. When it becomes smaller than X, the second correction unit movement amount △C is decelerated by the first correction unit movement amount △C'.
"An object of the present invention is to provide a method for controlling the deceleration of a table rotating shaft in a numerically controlled hobbing machine, which first decelerates the table.

FIG. 2 is a control block diagram of the numerically controlled hobbing machine of the present invention, in which each element having exactly the same function as in FIG. 1 is given the same number.

8 is a phase difference correction device which is the main part of the present invention,
A detailed internal embodiment is shown in FIG.

Reference numeral 9 denotes an AND gate that allows the unit movement amount ΔC stored in the register 3 to pass based on the determination result of the phase difference correction device 8.

Reference numeral 10 denotes an OR gate for allowing the correction unit movement amount ΔC' or ΔC'' to pass through from the phase difference correction device 8.

Reference numeral 11 denotes an OR gate for passing the output of the AND gate 9 or the OR gate 10.

FIG. 3 is a block diagram of a detailed embodiment of the phase difference correction device 8 shown in FIG.

Here, 12 is coupled to the cutting hob shaft, and the cutting hob shaft 1
It is an indexing signal generator that outputs one pulse per rotation.

13 is an AND gate that allows the current value of the table rotation axis to pass only when a pulse is issued from the index signal generator 12.

14 is a memory unit that stores constants, and is configured so that its contents are not lost even if the power is turned off.

In this embodiment, a value of 3600 indicating the reference position of the table base is stored.

Reference numeral 15 denotes a memory read control circuit that drives the memory unit 14 using a signal based on a pulse signal generated by the index signal generator 12 to read recorded data.

A subtractor 16 inputs and subtracts the current value of the table rotation axis and the data read from the memory unit 14.

17 determines the output value of the subtracter 16, and when the output value is within 1 pitch (3600°n is the number of teeth), the signal el I is output.
This is a phase difference determination circuit that outputs n, opens an AND gate 20, and passes a correction unit movement amount ΔC', which is an output of a divider 19, which will be described later.

Reference numeral 18 denotes a signal line into which the number N of pulses generated by the pulse generator 4 when the cutting hob shaft rotates once is inputted as a constant.

A divider 19 divides the output of the subtracter 16 by the number N of pulses input from the signal line 18.

Reference numeral 21 denotes an inverter that outputs a signal "1" to the signal line 22 to open the AND gate 9 only when the phase difference determination circuit is not outputting a determination signal.

23 is a signal line that inputs one pitch (3600) of the gear to be cut as a constant.

Reference numeral 24 denotes a subtracter which inputs and subtracts the output value of the subtracter 16 and the value of the one pitch.

25 is when a table rotating with unit movement amount △C is decelerated and rotated with corrected unit movement amount △C', and when △C' becomes an extremely small value, △C)△C' becomes, which is similar to a rapid stop. This makes deceleration control difficult.

In order to eliminate such inconveniences, this signal line is used to input the minimum setting value that allows deceleration, ΔX, as a constant.

26 is a comparator for inputting and comparing the minimum set value △X and the output value of the subtracter 24, and △X is the output value of the subtracter 24.
When the output value of 4 is positive, the comparator emits a signal ``1'', opens the AND gate 27, and allows the correction unit movement amount ΔC'' to pass.

28 is a divider that calculates a value △♂ that is smaller than the unit movement amount △C and larger than the minimum setting value.

29 is a deceleration compensation circuit composed of a subtracter 24, a comparator 26, an AND gate 27, and a divider 28.

Next, the operation will be explained with reference to FIG.

FIG. 4 is an explanatory diagram when reading the table rotation axis current value.

Reference numeral 30 denotes a table that can be rotated both clockwise and counterclockwise with respect to the base 31, and in this embodiment is rotated in the direction of the arrow as shown.

It is assumed that a gear as shown in the figure is being cut on the table.

A servo motor 32 rotates the table, and is driven based on the output of the table rotation axis function generating circuit 7 shown in FIG.

33 is an absolute position detector that outputs the current position of the table corresponding to the reference point on the base 31 when the table rotates, and outputs zero when the zero point on the table is relative to the reference point on the base 31. It is set to emit.

The output of the position detector is used for feedback of the servo system and as the current value of the table rotation axis.

Based on this, an explanation will be given with reference to FIG. 3. As long as the hob shaft is advanced from the reserved position when the zero point on the table and the reference point on the base match, and the cutting hob shaft and the table rotation shaft are continuously driven, The phase relationship between the hob axis and the table rotation axis is maintained, but if the power is turned off or the machine is stopped, there is inertia between the table rotation axis and the cutting hob axis. , does not stop immediately.

Therefore, the phase relationship between the cutting hob shaft and the table rotation shaft is irrelevant.

Figure 4 shows the above situation. For example, when the hob cutter moves forward from the hob shaft holding position and performs cutting, the hob cutter moves 200 degrees away from the table origin of the gear to be cut.

The cutting starts at point P, but since the phase relationship is unrelated, when the cutting hob shaft is rotated, the current value of the table rotation axis happens to be point P when a new indexing signal is issued. It shows that there was.

Considering the rotation direction of the table as shown in the figure, it is assumed that the table rotation axis zero point is within 1 pitch from point P.
Only the pitch rotates with a unit movement amount △C, and when the next indexing signal comes, the table rotation axis is decelerated to the zero point with a correction unit movement amount △C'. After correction, the cutting hob axis and table rotation axis are normal. It is designed to drive while maintaining the phase relationship.

To explain this in detail in Fig. 3, after the machine has stopped, in order to restore the normal phase relationship between the cutting hob shaft and the table rotation axis, first, only the cutting hob shaft is rotated so that a new indexing signal is generated. let

When the index signal is issued, the memory read control circuit 1
5 is driven.

Therefore, the memory unit 14 is driven and the stored data is read out.

The first index signal causes the constant 360° already stored in the memory unit 14 to be input to the subtractor 16 .

On the other hand, when the indexing signal is issued, the table rotation axis current value P passes through the AND gate 13 and is also input to the subtracter 16.

Therefore, the subtracter 16 subtracts the value of P from 3600, and outputs the subtraction result 360'-P to the phase difference determination circuit 17.

In the phase difference determination circuit, since 3600-P is not yet a value smaller than 1 pitch, no determination signal is output.

In this case, since a signal of output +1191 is generated on the signal line 22 by the action of the inverter 21, the AND gate 9 is opened and the unit movement amount ΔC passes through.

Further, the unit movement amount ΔC passes through the OR gate 11, and the table rotation axis continues to rotate at ΔC, rotates 4 pitches from the P position, and reaches the P point between A10 and A41.

The next fifth indexing signal is issued, and the phase difference determining circuit 17 determines that the value 360°-P of the subtracter 16 is within one pitch.

Therefore, it is determined that the phase difference α=360 −P is within 1 pitch, and the determination signal ++ 1 n
is issued to the AND gate 20, and the corrected unit movement amount ΔC', which is the result of dividing the value of the subtraction result 360°-P' by N by the divider 19, passes through the AND gate 20,
ΔC' is output.

As shown in FIG. 2, each time an output is issued from the pulse generator 4, the correction unit movement amount ΔC' passes through the AND gate 5 and is output to the arithmetic unit 6 and the table rotation axis function generation circuit 7, and is finally This is to drive the table rotation axis.

When the next indexing signal is issued, the zero point of the table rotation axis coincides with the reference point of the base 31, and after that, the table rotation axis rotates by a unit movement amount △C, and the hob shaft force is adjusted to The hob shaft is moved forward from the position, and cutting can be started while maintaining a normal phase relationship between the hob shaft force lever and the table rotation shaft to be cut gear.

However, as shown in Fig. 4, if the table rotation axis happens to stop so that α is extremely close to zero, then during the above deceleration operation, the normal unit movement amount △C suddenly drops to zero. The speed will be reduced to a value close to .

In order to avoid such inconvenience, the subtracter 24 and the comparator 2
6, an AND gate 27, and a divider 28 constitute a deceleration compensation circuit, which is added to the phase difference correction device 8.

Now, the table rotation axis rotates by a unit movement amount △C and is within two pitches of the zero point of the table rotation axis, and P is 329.5 degrees.
, when the next index signal is issued, P
is 359.5°, making deceleration extremely difficult.

In such a case, when P' reaches the position of 329.5°,
When the result 360 -P=30.5° of the subtracter 16 and the value of 1 pitch (3600,=30°) are input to the subtracter 24, the subtraction result of 0.5° is output to the comparator 26, Since the minimum deceleration setting value △X, for example 5°, is also input to the comparator 26 in advance, it compares and determines that 5°>0.5° and issues a signal "1" to the AND gate 27, which After opening, the divider 28 calculates, for example, △C ``one line S, and passes the antge 2 △C - 27, and the table rotation axis rotates by the correction unit movement amount T, and when the next indexing signal is issued. 34
4.5 degrees, and P reaches within one pitch of the zero point of the table rotation axis.

The above-mentioned ΔC' is calculated using the next indexing signal, so that deceleration can be easily performed.

In this embodiment, when the index signal arrives, the data stored in the memory unit is read out and calculated, but since these operations are extremely fast, the reading and calculation are completed instantly. However, the table rotation shaft is immediately driven.

As detailed above, the phase relationship between the cutting hob axis and the table rotation axis can be instantly restored when the power is cut off or the machine is stopped, and even when deceleration is difficult due to various factors such as inertia, it can be decelerated in several stages. Phase matching can be easily achieved through control.

In addition, in the embodiments of the present invention, in order to avoid complexity and make it easier to understand, the table rotation axis is rotated in one direction, and the table rotation axis is controlled, but the hob axis is not controlled. Of course, it is possible to realize the present invention in any case.

[Brief explanation of the drawing]

Figure 1 is a control block diagram of a conventional numerically controlled hobbing machine;
The figure is a control block diagram of the numerically controlled hobbing machine of the present invention, Figure 3 is a block diagram of a detailed embodiment of the phase difference correction device 8 shown in Figure 2, and Figure 4 is an explanation when reading the current value of the table rotation axis. It is a diagram. 4... Pulse generator, 8... Phase difference correction device, 12... Index signal generator, 29...
...Deceleration compensation circuit.

Claims (1)

[Claims] 1. A pulse generator and a cutting hob shaft that electrically drive the cutting hob shaft and the table rotation shaft separately to control the rotation speed ratio and mutual phase relationship with the cutting hob shaft. In a numerically controlled hobbing machine controlled using an indexing signal generator that emits one signal per rotation, the mutual phase relationship between the cutting hob shaft and the table rotation shaft, which have become unrelated after the power is cut off or the machine is stopped, is restored. In this case, when it is detected that the phase difference between the current position of the zero point on the table and the reference point of the table base is within one pitch of the gear to be cut based on the signal of the indexing signal generator, the unit of the table is determined. In place of the movement amount △C, the first unit movement amount △C is smaller than the unit movement amount △C.
Phase matching is performed by decelerating by the correction unit movement amount ΔC', and based on the signal from the index signal generator, the difference between the phase difference and one pitch of the gear to be cut is set to the minimum setting value Δ that can be decelerated. When it is detected that the unit movement amount is smaller than X, the unit movement amount △C is
A method for controlling the deceleration of a table rotation axis in a numerically controlled hobbing machine, characterized in that the second correction unit movement amount △C" is smaller and larger than the long line minimum set value △X. .