DE2351592A1 - Control of tooth flank roller grinding machine - has store between subtractor and comparator to store highest pulse of cutting output - Google Patents

Abstract

Control of a tooth flank roller grinding machine with an output indicator for each grinding disc drive, required value adjusting block for the allowable cutting output, subtraction circuit to deduct the idling output and theoretical/actual comparison block to compare the given cutting output with that measured by the indicator, which is connected to a control circuit for the table feed speed at the grinder. A store is connected between the subtraction circuit and the comparator block and this stores the highest pulse of the series of cutting output pulses given by the subtraction circuits. There is also a unit connected to reduce the over control, which is connected with a control circuit for the table feed speed and is set up to determine the first time the grinding disc contacts the workpiece and to change over an accelerated table feed movement.

Description

Permskij politechniceskij institute

TO THE STKJiSUMi EIHER
MASGHIHS

The present invention relates to the field of mechanical Machining of workpieces and can be used in mechanical engineering companies in the highly productive machining of gears with increased demands on manufacturing accuracy and Surface finish. Find use.

Devices for controlling Grinding machines, which include active power transmitters, the outputs of which can be drawn off via sub-jbraction holds the no-load power of the grinding wheel drives, with a Setpoint setting block for the permissible cutting performance and with a speed control circuit for the table feeds Grinding machine are connected

However, these controllers' iron limited setting accuracy of the ImpulsschnittIeistung Zahnflankenabwäl ζ abrasive s, and therefore the Abwälzschleifmaschinen mentioned reach only a small performance at the workpiece machining, ie the use of known control devices is hereby at an incision ^mi ^. .

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The lower motor power does not change the table feed speed leading to table speed fluctuations ■ These sharp changes in table speeds during workpiece machining but are not permitted for technological reasons. In addition, there can be a sharp change in table speed Liquid shocks in the hydraulic system of the grinding machine causing a loss of accuracy of the machine and its faster wear and tear.

The elimination of the above-mentioned disadvantages of the known control devices for controlling the grinding machines, -in particular . Tooth flank sciile if machines are provided, thus became the aim of the present invention.

In order to achieve the stated and other objectives, the present invention is based on the object of such To develop a device for controlling the tooth flank grinding machine in conjunction with a control circuit for the table feed rate means for checking the respective operating status of the grinding machine and for Maintaining an appropriate level of cutting performance be applied, the greatest machining accuracy of the workpiece can secure.

In order to solve the given task, the device for controlling the tooth flank Abwälzschle if machine that

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Active power transmitter on each grinding wheel drive, setpoint values instell block of the permissible cutting power, traction circuit for subtracting the idle power, target / actual -fergleichblock for comparing the target cutting performance with the cutting power measured by the over, which is transferred to the Control circuit for the ΐ isch feed rate of the grinding machine is connected, includes, according to the present invention between the subject matter of the idle power and the target / actual comparison block, a memory switched on, which is used to store the maximum pulse from the

the

Series of switching circuits for reducing idle power given cutting power pulses is used, to which a unit for avoiding overload is connected, the is connected to a control circuit of the table feed speed and for setting the moment where the Grinding wheel touches the workpiece to be processed, and to switch the iDisch from accelerated feed to one The feed required for operation is set up according to a prescribed transmission law.

According to one of the embodiments, the invention contains said memory a reverse pulse counter that has a Key matrix is connected to a bull organ, which the reverse pulse counter he gives filling pulses, with the mentioned pulse counter on reset the pulse counter

is coupled to the time element. This time element is one

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Pendelungszahlgeber of iSchle if bocks connected with the position of the grinding stand and to the control circuit of the table feed speed ^v over logical AND element for the purpose of synchronization of the storage and processing times.

Another embodiment of the present invention

provides that the target / actual comparison block at its output

a
with the reverse pulse counter via ^ sign output block of the

given

Difference signal ·, between the ^v cutting power with the regulated maximum power and with the. Control circuit of the table feed speed of the tooth flank grinding machine is interconnected.

The mentioned unit for avoiding the overload can

designed as a time element »earth that a train of pulses, of a certain frequency, to the control circuit the table feed speed at the time there where the grinding wheel is in contact with the workpiece comes.

It is usually the one connected to the memory Subjbraktionskreis the idle power according to the invention in the form of one after the other at the output of the active power transmitter switched chain, consisting of a storage capacity and to design a diode whose signal arrives in the memory through an emitter follower.

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Will the above structural features to reality, it is in particular the fact that the control device according to the invention is a bumpless one Change the table feed speed on the tooth flank chi e if machine while maintaining its optimum Size, i.e. such a size that the Maximum value of the .cutting performance on the most heavily loaded drive motor the grinding wheel the required surface quality of the workpiece and the prescribed machining accuracy is equivalent to·

The present invention is explained below with the aid of an exemplary embodiment which does not restrict the scope of application and the accompanying drawings, in which it shows:

Fig. 1 overall block diagram of the device according to the invention to control the tooth flank grinding machine;

Pig. 2 Subtraction circuit for subtracting the idle power.

Is should be noted that without Invoices the interconnection of the self-steering system for the grinding machine with prescribed high parameters the manufacturing quality only on experimental. Ways is extremely complicated.

The highest accuracy in maintaining a prescribed level of performance can be achieved with the application of a

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automatic digital control system can be achieved. About that In addition, the digital control system shows in comparison to the inalog control a faster effect, increased operational reliability and better voting convenience. Convenience must also be added to the door parts of the digital control and objectivity of digital data input, signal reproduction as well as the convenience of association of digital controllers with digital facilities for data processing. As a result, in this regard, the

the

To describe digital control systems as the most promising, all the more so that the controlled variable itself is a pulse variable. Information about the cutting performance in machine tooth flank grinding can only be obtained in discrete time slots. This condition arises from the frictional connection Workflow in the rule object. Because of the above is the block diagram of the control device for maintaining the corresponding cutting performance size for tooth flank grinding compiled as follows (Pig. 1). In Pig.l the block diagram is the proposed Control device shown, the fiction ungsgeniäß of two Active power generators 1 and 2 are made with subtraction circuits 2 and 4 to subtract the idle power of the Drive motors (not indicated) of the grinding wheels assembled which in turn are connected to an OR element 5. This element is at its exit with

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brought a memory 6 in connection ^wel: consists clier from a Hullorgan 7, which is connected übeijein logical OR element 8 to the input of a reverse pulse counter 9 whose output matrix via a circuits 10 to the second input of the zero element 7 in compound '! stands. The reverse pulse counter 9 is coupled by means of a timing element 11 to a pendulum counter 12 of the bench grinder of the tooth flank grinding machine. The output of the key matrix 10 of the storage

"ei *" ■ ■ "''" "■" ■ '■'

chers 6 and a) the inputs of a target / actual comparison block IJ are interconnected, while at the other input of the comparison block 15 a setpoint setting block 14 of the permissible Cutting power is switched. The output of the target / actual comparison block 13 is with a

Differential signal block 15 between the target cutting power and actual average performance and a logical and - Link 16 with a control circuit 17 of the table feed speed connected to the tooth flank grinding machine. The differential signal block 15 is at its output with the Reverse imp ul s number he 9 and the control circuit 17 are coupled. The OR element 5 is at its output via a time element 18 of a unit 22 to avoid overdriving interconnected with one of the inputs of the logic AND element 19, while the other input of this AND element 19 is connected to a pulse generator 20. To the

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cerium

The output of the AND element 19 is one of the inputs of the control circuit 17 the table feed speed on the tooth flank

21
ε-cnle ifmaschine ^v connected.

The control device according to the invention works as follows. When grinding gears on the ellern with two grinding wheels operated tooth flank hobbing machines cut these One after the other, insert the sanding disc into the tooth of the K @ .des by they use their drive motors. The ones from the network

recorded by these drive motors and by the encoder rs shared

1 and 2 fixed ^ real power is not only the sole if-

cut, but also, for the idle losses consumed. Around to increase the precision of the impulse cutting performance, is used in the subtraction circuits 3 and 4 to be removed

(-loss-) .

the idle power from that proportional to the total active power Signal proportional to the running idle power Signal withdrawn. In this way, 6 signals come into the memory, with only the cutting power in the correct ratio stand. The reverse pulse counter 9 is hereby pulses generated in the zero organ 7 filled up. This replenishment

the

of the reverse pulse counter 9 happens until ^ from the OR -Element 5 supplied measuring voltage at the output of the key matrix 10 outgoing step voltage becomes the same. When these voltages are equal, the zero organ 7 stops, impulses on the reverse pulse counter 9. As a result, a digital code is filled in this meter, which corresponds to the maximum

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value corresponds to the cutting performance. After the cutting power impulses have arrived from both S grinding plates, the oscillation counter 12 of the grinding book gives a command on time element 11. This time element 11 opens the logical changeover element 16, through which the difference signal

that passes through that of the difference between the permissible cutting power resulting from the condition of obtaining preparation of a desired surface quality of the workpiece or from the achievement of a prescribed machining accuracy (it is set on the setpoint setting block 14) results, and the largest reported by the memory 6 actual average power of both drive powers of the right ν left The drive of the sanding pad is proportional. The sign of the difference is shown in the difference signal block 15 determined. The delay time at time element 11 is so great set so that the information about the maximum values of the cutting performance is not lost, i.e. it should be smaller can be chosen as the time interval between two maximum values the cutting performance on both sanding discs. The difference-

signalg _{r 5ß e} j £ _Omm t through valve logic element 16 to the control circuit 17 of the table feed speed on the tooth flank grinding machine 21 and increases or decreases this table feed speed depending on the

Difference ^ sign. If the actual cutting performance exceeds the exceeds permissible, the feed speed of the

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- lü -

iisches and thus also the cutting performance is reduced. At the same time, the difference signal size in the control circuit 17 is converted into pulses that occur at the input of the reverse pulse ul s counter s 9 through OR element 8 until the output voltage of the key matrix IO reaches the size of the voltage at the setpoint setting block 14, dn to the difference has become zero. - ^T he switched in the reverse pulse counter 9 an addition or Abaugsoperation accepts the difference signal block 15 in dependence of the difference signal sign. Dad urea, is the proportionality of the processing of the difference signal magnitude by the control circuit 1? obtain. After the processing of the difference signal has taken place, the timing element 11 erases the digital variable stored in the reverse pulse counter 9 of the memory 6 with the back edge. As a result, the memory 6 is ready again to store the maximum value of the following pair of cutting power pulses, and the control cycle is repeated.

An override occurring at the beginning of the cutting into the tooth of the wheel is eliminated by the unit 22 for avoiding override, which sends a signal to the control circuit 17 of the table feed rate only at the first point in time when each grinding plate touches the wheel tooth. With this first contact of the wheel tooth with the grinding plate, the timing element 18 opens the valve logic

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AND element 19, which is a pulse train of such a frequency from the pulse generator 20 lets through that the interlocking of the control circuit 1? the speed of movement of the table downsized by a law in which the cutting power is based on is maintained at the prescribed level (if necessary after, a linear law).

The subtraction circuit connected together with the memory 6 5 or 4 to subtract idle power reproduced in Fig. 2 and contains a sequentially connected to the output of the active power transmitter 1 or 2 chain from storage capacity 25 and diode 24. The signal of the diode 24 arrives in memory 6 via emitter follower 25.

vtfird is a grinding wheel drive motor of the tooth flank grinding machine for example with two sole dividers in the When idling (at the beginning of the sole process), then the storage capacity 25 by one of the no-load active power proportional signal charged via blocking resistor of diode 24, until a voltage proportional to the no-load active power is reached.

Increases the performance (cutting into the cutting tool in the »package), the voltage at the output of the increases Encoder 1 or 2 strongly. When machining workpieces on tooth flank grinding machines of various types the output voltage of the encoder 1, 2 in the form of the Sennitt power proportional impulses, the duration of which

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Customer Disadvantages Nods Exceeds. During the effective time of the cut tmp ul s es the voltage on the storage capacity increases only insignificantly, and the total voltage, which is only proportional to the cut effective power, is applied to the diode in a non-conductive direction. The emitter follower is used to transfer this signal. When the load drops to that of no-load operation, the only insignificantly recharged storage capacity 22 discharges very quickly via the forward resistance of the diode 24 to the voltage that corresponds to the respective no-load power. If the no-load power is increased when the electric drive is in operation, the storage capacity 23 is gradually charged up to a new voltage that corresponds to the new no-load power value, the cutting power pulses accelerating this charging process. But if the no-load power becomes smaller, the voltage across the storage capacity also decreases in high gear to its new value by discharging through the resistor of the diode 24.Consequently, the voltage across the storage capacity of this proposed contactless device is always proportional to the no-load power and follows their changes during operation of the electric drive.

In this way, with dynamic loads on the electric drive, only signals are picked up by the diode and

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transferred that practically only consumed that of the, sons Performance are proportional.

The present invention made it a 1.5 fold increase the machine performance for tooth flank grinding Preservation of the prescribed processing quality of the surface layer achieved. ,

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Claims (4)

PATENT CLAIMS: (1. j device for controlling a tooth flank hobbing machine with active power transmitter for each grinding wheel drive, setpoint setting block for the permissible cutting power, sutu-trsection circuit for subtracting the idle power ^v nominal / actual comparison block for comparison the the prescribed cutting performance with that ^{measured by the Y} encoder, which is sent to a control circuit for the table feeds rope
speed is connected to the grinding machine, characterized in that a memory (6) is switched on for storing the maximum pulse ^{between the sub ^ fcraction group O - 2 O for subtracting the idle power and the target / actual comparison block (13)} the series of by the sub ^ braktionsschaltungen (3 and 4). for subtracting the idle power given cutting power pulses, to which a unit (22) is also connected to avoid overdriving, which is interconnected with a control circuit (17) of the table feed rate and to determine the first point in time when the grinding wheel touches the workpiece to be machined, as well as for switching an accelerated table feed movement to an operationally required one according to a given occupation. 509821/0370 -.15 - 2. Set up according to. Claim !, characterized that said memory (6) contains a reverse pulse counter (9), which has a key matrix (10) to a replenishing to the reverse pulse counter (9) Impulse-giving bull organ (7). Is connected, with the said reverse pulse counter (9) a counter resetting time element (11) is interconnected, which is connected to a Pendulum counter (12) of the grinding block and a control circuit (17) of the table feed speed via a logic AND element (16) for the purpose of synchronizing the processing times is related to the position of the bench grinder. 5 »Device according to claim 1 or 2, characterized indicated that the target / actual comparison block (13) at its output with the reverse pulse it counts (9) over a difference signal block (15) of the difference signal of the specified cutting performance and the regulated maximum output as well as with the control circuit (17) of the table feed speed the · tooth flank cutting machine held together is. 4. Device according to claim 1,2 or J, d adur ch gekennze i c h η e t that the unit to avoid the override is designed as a timing element (18), the output of a series of pulses at a certain! frequency the control circuit (17) of the table feed speed 509821/0370 only at the first point in time when the workpiece comes into contact with the abrasive clamp 5o establishment after any Inspraoh 1 to 4 ₃ dadarcto. gek@nu.z Brilleioiinnahmt _s that the saliva? (6) connected © Sab ^ tralctionssehaltüÄg (J or 4) exerts emptiness © in © height to the. Aasgang des Ä'irkl © istaogageb @ rg (1 oü®s 2) g © sehalt © t © iLett © represents storage capacity (25) and Diocl® (24) via the signal _s as ¹ (25) i & 509821/0370