DE2001357A1 - Device for controlling the feed of machining tools or the like. - Google Patents

Description

PATENT LAWYERS

DIPL.-INQ. F. THIELEKE dip. PHVS OR j PRiCKE

DRMNQ. R. DOERING DIPL.-PHYS. OR. J. FRICKE

BRAUNSCHWEIG MUNICH

Micromatic Hone Corporation, Detroit, Michigan / USA

"Device for controlling the advance of machining tools or the like."

Me present invention relates to a device for Control of the advance of machining tools or the like. ".

In devices of the type mentioned at the outset, at least one of the influencing variables of the processing carried out on a workpiece is monitored on the processing surface, and at least one processing variable is changed as a function of the values determined in the process, so that a previous. "A certain standard or quality of the work carried out .upright- -.- ■. can be obtained. Devices of the 'type' mentioned at the beginning can, however, also be used to carry out a rapid advance of processing tools, which is followed by a slower processing advance allow devices of the type mentioned machining operations in which the machining tool short strokes or a strong and heavy in processing. certain

Automatically carries out surface areas.

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In the past, the feed of the Machining3 tools was essentially based on a preset. For example, when honing, the honing stones have traditionally been run into the tool at a preset speed or force and also set in rotation at a preset speed, the size of which was based on empirical values. Such a tool feed can W naturally the normal changes out of consideration arising within the material of the honing stones or within the material of the machined workpiece. As a result, such machining operations are often carried out with a lower degree of efficiency than desired, and it is often not even possible to maintain the required level of quality.

In the past, when control of tool feed into a workpiece was carried out during the machining operation, this control was mainly carried out by specifying start and stop. This type of control was carried out in the manner that a machining parameter was monitored and the feed of the tool, ie either its feed, interruption or start, was controlled depending on how close the monitored machining parameter was to two acceptable opposing limit values. Such controls of the feed lead to an intermittent tool advance, the consequence of which is that the machining is below the . ,, .-, - ,,, 009846/0996

ea.:

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hvibea, revealed, ^ zu siteueiTi, ui e, ^ w ^ special Bear "ejfi at those ^ points of a WerJta ^ iic ^ es, eoif dep 'length of the machining stroke where. such, Stonder- »^ qtwend-ii ^. are. AujSe _r r _; d, eta va ^ en ^ ie, zur SteHfrung- de ^ Vierk? fugv ^ rscbub.e ^ E uji ^ t in itjtoer, A ^ iwe.ndun ^ unviijf ^ sheep ^ liejh ^

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200 I 357

a device is provided which monitors at least one of the plurality of machining parameters, while a. further device at least one of the input machining parameters continuously changed depending on the monitored size, for example in the sense of maintaining constant cutting conditions on the machining surface. The new device can be used both with electric, mechanical or hydraulic tool assemblies W respectively are connected -ausbi fertilize!.

Except for maintaining or creating constant cutting conditions on the contact surface of a cutting tool with a workpiece, the device designed according to the invention can or the new method can also be used to rapidly advance the cutting tool to the workpiece Without the use of attacks or the like. To make and fe im. This is followed by a slower tool feed for the

Initiate processing. With the new device respectively.; according to the new method, the cutting tool can also can also be controlled in the sense of a short stroke, for example in order to carry out processing in specially designated areas of the W & afetüefces To make.

This is the case, for example, with honing with the neum gearing . According to the new procedure, a feed dame k is possible

a speed that generates a voifrestinffiteä ment at the processing spindle,

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the desired material removal on the workpiece surface or quality of the surface treatment or both.

Embodiments of the invention emerge from the following Drawings. ...> ...

Show it: "

Pig-. 1 partly as a block diagram and partly as a schematic drawing Executed picture of the new device designed according to the invention for controlling the feed Of machining tools or the like. Which also for Implementation of the new method is suitable, wherein the machining tool is a honing tool,

Pig. 2 shows an illustration, partly as a block diagram and partly as a schematic drawing, of the device according to - Pig. I ₁ which the ^^;, Stro ^ .t, 2 ^ eu k ^ _f E4S Jn details reproduces:?; * .: · .- ■ ■ ..--, "■ ' ■.., · ■" ■ - ■'. .

Pig., Figure 3 is a schematic drawing of the device in use for a tool whose spindle is driven by a fluid motor, ^,, - ■

Pig. 4 is a schematic drawing for the device according to Pig. 3 showing the design ^ for the. Achieving a con-. -; constant spindle speed shows

Pig. Sosine. Scheme drawing aääer -invention trained according to the invention >: VorrJ.chtu] ag at. AmsMlctuJig for a fast feed

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of the machining tool, which is converted into a slower machining feed rate when the workpiece is touched,

Pig. 6 is a schematic of the new device in training for quick short strokes of the tool.

In the pig. 1 shows a device 10 for controlling the pre-P thrust of a honing tool 12. Honing tools are known and therefore do not need to be explained in detail at this point. Honing tools 12 have a spindle 14 on which honing stones 16 are arranged to be radially movable in the direction of arrows 18. The radial movement is generated in that wedge surfaces 22 on the spindle 14 are moved in the direction of the arrows 20. The spindle 14 is driven by a spindle motor 24, which is shown as an electric motor 26 performed by a hydraulic feed cylinder and is carried out depending \ Driicke which act on the two opposite faces of a piston 28 in the hydraulic cylinder.

The device 10 has a current transformer 30 and a current converter 32 as well as a current control circuit 34 and a solenoid valve 36 on which in the Pig. 1 are in communication with each other. The transformer 30, current converter 32, current control circuit 34 and the solenoid valve 36 are used to control the pressure in the hydraulic feed cylinder 26 as a function of

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ke / it VOir the torque ",, - with which em the Spintlelmötor 2 £ be> ~ load * will change.

Dei? StrbmtranslOrmator 3®. In an electric power source 38 turned on, and serves to feed the Spi moto: fes 24 which · _v rotation of Spinael 14 The: .beideutet, an electric Eingangssignai DAT on Stforotransforniator 30 that inserts into Aühängigiceit with the loading Λ burden of: Kotores ,; ie changes depending on the load torque. The load on the rotor 24 changes as a function of the cutting conditions on the contact surface between the honing stones 16 and a workpiece that is being honed (not shown).

It is known in the cones that the Mater alabtragung or machining is greater at the surface of the machined workpiece, the torque of the gröSer the onerous Hotora = .2 $ · - of the actual Vö £ _r auseetzung that df e Hbnsteiine 1 € -

Work without walls. If, however, the colored stones tend to become sluggish, then an essentially fine-grained movement occurs; Torque: des ^; Moiiöases ^ a. That means that at Hona3? Work: k ^ msröante; Cutting or cutting conditions with the contact surface between the honing stones and? Deffl ^ prevail - if the> torque with which the motoir is: and the iniölges instead on the Sp & del 14 remains in control.

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The current, which, for example, has a magnitude of 5 A at the output terminals of the current transformer 30 under normal honing conditions, is passed on to the current transformer 32 via an ammeter 40. The current transformer 32, which in turn, is a commercially available copy is the input current is converted into a voltage drop occurring at a resistor 42 and whose size propor- FSS tional to the input current and the magnitude of the input current, the 4o the ammeter indicates changes. The output current of the current transformer 32 has that in the Pig. 1 and 2 registered polarity and can be selected, for example, so that there is a 2 V voltage drop across the resistor 42 per ampere input current of the current transformer. The current flowing through the transformer 30 and the voltage drop across the resistor 42 change with the size of the motor 24 and are also greater when the torque of the motor 24 is greater.

The current control circuit 34, which is more detailed than in Pig. 1 in the Pig. 2 has a direct current source 38 with regulated output voltage on the order of, for example 5 V, which can be tapped, for example, at a resistor 50 and whose polarization is shown in the figure is. The size of the output voltage is determined by a Voltage regulator 53 and a setting resistor 55 are determined. The direct current source 48 also supplies the potential for a DC amplifier 57. The voltage tapped off by the resistor 42 by means of a movable grinding control arm 44,

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which is passed on via a resistor 46 is through Moving the sole if contact arm 44 changeable: and can be about 10 V, for example. ■

When the current control circuit is in / operation 34) are electric signals of opposite polarity, soft at the resistors 42 and 50 picked up, are passed through a resistor 54 and compared in a comparative · or subtraction ■ circuit 56 together to produce a Differenzsighäl to generate * which is fed to the DC amplifier 57. The amplified differential signal is then passed through a resistor 58 and protective fuses 60 to the excitation coil 62 of the solenoid valve % in Pig. 1 directed «

The resistor 50 is equipped with a sole contact arm 64, so that the reference voltage j corresponds to the voltage from Resistance is compared, set to any value can be customized to specific machining characteristics at the contact surface between the honing stones 16 and the workpiece, to set and corresponding removal sizes or Machining grades or combinations / of these parameters Select. ■ ■;

Das., Solenoid valve 36, which is described in Pig. 1 is shown, is an order item and is not explained in detail ... This valve is, however, switched on in a hydraulic line 66 * which leads to the feed cylinder 26. The! Activity

Q0SS48 / 0996 ^J.

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This valve consists in changing the pressure of the hydraulic fluid which is supplied to the hydraulic cylinder 26 as a function of the electrical signal in the excitation coil 62. If the positive direct electrical signal in the excitation coil 62 rises or becomes greater, then the pressure with which the hydraulic cylinder 26 operates is also increased. This, in turn, an increase in yields of Be lastungsdrehmomentes-Kotores 24 "which results either by increasing the depth of the Honschnittes can also be calculated by the breakage of the smooth become Schmirgelpartikelchen in smooth become honing stones 16, which through daa breaking new cutting surfaces of the honing stones 16 .

If there is no load on the spindle motor 24 during operation, i.e. if the honing stones 16 are in the air, a certain minimum torque is then still applied to motor 24 removed to keep the spindle 14 rotating. With this low load it is necessary to have a certain minimum feed pressure in the hydraulic cylinder 26 is available. At maximum load, the maximum pressure is determined by the appropriate setting of the sliding contact arm 64 is selected. This setting results in a corresponding signal at the excitation coil 62. This waximal feed pressure can be 14 kg, for example per square centimeter in the pre-lift cylinder are 26, if a certain Low voltage signal of negative polarity emitted by the current transformer or applied to the resistor 42.

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When the torque with which the motor 24 "is loaded increases, because the honing stones 16 have come into contact with a workpiece as a result of the feed or because the grinding particles, which were previously smooth, became sharp again through breakage, then there is an increase in the negative tension at resistor 42, through which the positive signal dea resistance 50 in comparison circuit 56 is reduced, so that the signal which is supplied to the valve 36, accordingly is reduced to the pressure in the hydraulic line 66 ζμτη Hydraulic cylinder 26 to lower until a state of equilibrium between the fourth of the pressure in the feed cylinder 26 and the torque with which the motor 24 is loaded, entry. This state of equilibrium in turn represents the desired constant machining state on the contact surface between the honing stones and the workpiece.

Any subsequent changes in the This way, optimal machining conditions achieved on the contact surface of the honing stones with the tool leads to a change in the torque with which the motor 24 is loaded will. However, this results in a corresponding change of the pressure in the feed cylinder 26, which takes place instantaneously and takes place in the direction that stable optimal cutting conditions on the honing surface are maintained. The balance between the machining parameters as such can be changed by moving the sliding contact arm 44.

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In the pig. 1 and 2 was related to the new device with hydraulic tool feed and electric spindle motor 24 ". It should be noted, however, that the new Device is not limited to this type of drive and feed of machining tools, but instead in connection with electrical, mechanical or hydraulic or other drive devices for generating the Spindle rotation as well as for generating the tool feed can be used. It should also be mentioned that the described device according to Pig. 1 and 2 are also used in applications other than those explained in the example can be.

In the example shown in Fig. 3, there is a liquid motor 70 provided to drive the spindle, and it is the current that a motor 72 draws to a Plüssigkeits-P To drive pump 74, used to generate 30 signals in the current transformer. The remaining part corresponds to the device in its execution of the form that is in the Pig. 1 and 2 is shown. With the liquid engine according to Pig. 3 and the device according to Pig. 1 and 2 can also continuously maintain constant honing conditions on the honing surface will.

If the liquid motor 70 is used, then, as shown in FIG. 4, a motor control device 76 with a potentiometer pressure transducer can also be used 78, a speed logic control

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circle 80 and buckets servo valve -82 can be used to control the Forsohubdruek depending on the working pressure on the liquid.s? - change engine. At higher;, adjacent to the liquid motor Press is the Ijeckfliiasii, ^ ceitsme.nge, the # ure.h den The volumetric flow rate is greater than at low pressures.

As a result, in order to obtain a sufficient quantity of liquid pumped by the liquid motor 70

must be in order to maintain constant honing conditions on "the second day on ^ Λ

reehtauertoalten, the amount of liquid that is passed through the servo valve 82 flows continuously from the GresphWindiigkeits ^ lOägikateuerkreis 80 set.

Ln -der Motorsteuerereinriehtu.ng? 6 signals that represent- ^ tati'v for the pressure on the liquid motor 70 and welehe , but also representative values for the conditions at the Honing surface are in the speed logic control circuit 80 fed to the Yentil 8.2 to open or close and ^

In this way either more or less of the pump 74 liquid delivered either to the motor 70 or to the liquid source traced back. At higher pressures., At which the servo valve 82 is more closed, a larger portion of the dea? Pump 74 pumped liquid over the Motor 70 passed, and the leakage amount is now from the motor 70 according to the .Steuvorvorgangs im Geschwindig ^ keitslogiksteu.erkreis generated so that the QJaction of the engine 70 4Not affected by changes in the amount of leek fluid can be. -

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In the embodiment of the device shown in the ^ i ₀ O, the torque is, is charged with which the spindle motor, used to BZV the contact of the tool /. determine the emery stones 16 of a grinding tool with the workpiece, in that the increase in torque that occurs when contact is made is measured or fixed. The signal supplied by the current transformer 32 is used to actuate a speed or feed control switch 84, whereby either the fast feed device 86 or the slow feed device 8ü are set to move the emery stones 16 onto the surface of the workpiece to move towards or away from this. With this design of the device for controlling the tool feed, it is possible to make a rapid feed movement of the grindstones 16 towards the workpiece or away from the workpiece and then, after the rapid feed, to make a controlled or slow machining feed of the grindstones 16 in order to maintain constant grinding conditions create and maintain without having to work with stops or other particularly precisely adjustable control aids on the workpiece or on the grindstones.

In the same way, the new device for 'control de3 But feed of machining tools can also be used to carry out short strokes of a honing tool. Such For example, short strokes are advantageous or necessary when in a cylindrical bore, for example a rifle

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BATH

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running, sealing surfaces are available ... For example, it is undesirable the entire length of a rifle barrel in the honing operation to be covered with the honing tool if only certain intermediate parts of the barrel, on which there are sealing surfaces, need to be honed. For example, it may be much more advantageous to identify such a sealing zone and Only move the Konspindel forward in this area and only honing over the lungs of this sealing zone and then moving back again or to hone the entire barrel of the rifle and the spindle when a sealing zone occurs or is detected take off and interrupt the honing process until the sealing zone has been passed and then the entire rest of the working stroke in the honing process over the remaining length of the gun barrel or continue until another sealing point occurs.

6 shows a Kub control switch 90 which responds to the reduced torque on the spindle motor,

This is the result when the honing stones are “made from a grinding surface in

emerge from a hole through which the working stroke extends. The switch 90 is operable at such times to operate an upstroke or downstroke reverse circuit "9-2 or 94 to effect a corresponding operation of a lift cylinder 95 in FIG. 6. If, for example, the machining tool , in particular honing tool enters a sealing surface in a bore, while it is in machining stroke, the switch 90 is in the willingness

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state triggered and the honing tool moves depending on the direction in which it was originally started has been, downwards or upwards. As the tool moves out of the sealing surface, the size will be reduced of the torque determined by the device 10 according to FIG. 1 and causes a reversal of the feed direction. the The sealing surface of the bore is therefore honed again. This reversal also occurs at the other end of the sealing area of the bore and is continued until the sealing area of the bore is essentially the same as that of the neighboring one Bore parts is expanded, if so desired. Then the normal working stroke continues until a new sealing area is detected.

Although a detailed embodiment and several modifications of the device for controlling the Feed of machining tools and the method for controlling the feed of machining tools explained it should be noted that other embodiments and modifications possible are.

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Claims (10)

2ÜU1.3S7 Pat ent befii oh e / 1.1 Device for controlling the feed of machining tools or the like * * thereby g e k e η η ze i without t that an adjusting device (26) for At least one machining partner and a heating device (30) are provided for at least one machining parameter, and one depending on the heating device working actuator (36) between the Mihleinrichtüng and the setting device is arranged * around the setting device in the sense of keeping the To continuously control machining conditions on the machining surface. 2. Apparatus according to claim 1, d ad urch ge te e η η «ζ calibration η e tj that the adjusting device for the tool feed and the cooling device for monitoring (| the torque of the drive motor (24) for the machining spindle (H) are provided ., 3. Vorriehturig according to claim 1 and / or 2 * d a d u r c h g e k e η η ζ e i c h η e t »that the grinding device as electrical device (30) is formed which generates a milling signal which is proportional to at least one of the machining parameters and that the actuating device a voltage source (48) for an electrical reference voltage as well as a comparison device (56) 2üü which the sense signal with the signal of the 3supply voltage3 source compares and generates an output signal proportional to the difference between the two signals. 4. Apparatus according to claim 3, characterized in that that the output signal is greatest with the lowest processing parameters sensed. 5. Apparatus according to claim 1, characterized ge kenn ζ e i without t that the setting device for setting the feed rate is formed, ura the feed rate of a higher fourth at the beginning Set contact of the workpiece to a lower value. 6. Apparatus according to claim 1, characterized in that that the adjusting device is designed to adjust the stroke length and one when it is reached a certain value of the sensed processing parameter in action reversing device to reverse the stroke direction. 7. A method for controlling the feed rate of machine tools or the like., Characterized in that, that one of the machining parameters is monitored and the same or a different machining parameter is dependent of the changes detected by the monitoring 009846/0996 ORIGINAL (NSPECTED is controlled continuously. 8. The method according to claim 7 »marked thereby e i c h η e t that the torque of the drive motor for a machining spindle is monitored and the tool feed is controlled. 9. The method according to claim 8, characterized in that that initially a high feed rate is discontinued and maintained until the Torque of the drive motor for the machining spindle indicates the contact of the tool with the tool and that then a lower feed rate for the Machining of the workpiece is stopped, 10. The method according to claim 1, characterized in that the length of the stroke of the tool feed is controlled and changed or reduced when the sensing device detects a sealing point on the workpiece . -