DE102022119894A1 - Measuring bezel, turning-milling machine equipped therewith and method for its operation - Google Patents

Abstract

In order to avoid both space within the machine and dead times in the machining process, the invention proposes measuring the circumferential contour of the workpiece (W) using the steady rest (100), preferably directly during the machining taking place next to the steady rest (100). of the workpiece (W), and in particular by determining the relative positions of the supporting bodies (102, 103) of the bezel (100) relative to the workpiece (W), i.e. without an additional measuring device (106) on or in the bezel (100), However, this depends on the parameters of the circumferential contour to be determined.

Description

I. Area of application

The invention relates to a bezel that is used at or near the machining point in a material-removing tool machine, for example in a turning-milling machine, to support the workpiece against machining forces, the bezel having a measuring device for measuring at least the Diameter of the workpiece on the outer circumference supported by the bezel, which is usually cylindrical.

Roundness deviations can also be determined here.

II. Technical background

In the case of tool machines in which the outer diameter of mostly wave-shaped workpieces is to be produced by material-removing processes with a specific or indefinite cutting edge, a mostly rotationally symmetrical outer circumference is generally known, either directly at the axial position of the machining or as closely as possible axially adjacent to it to support the workpiece against the machining forces applied by the tool.

On the one hand, a distinction must be made as to whether the bezel includes rollers as support parts with which it rests on the workpiece, which is necessary if the workpiece rotates relatively quickly during machining, or whether the support parts instead have sliding surfaces, which is only possible is when the workpiece stands still during machining or only rotates slowly, such as in turning-milling using a milling cutter with external teeth, for example, in which the workpiece rotates slowly at best and only rotates a total of over one revolution per machining step.

A further distinction must be made as to whether the bezel supports the workpiece only in one support direction, i.e. rests against the workpiece only on one side of a diameter line through the workpiece, or whether it is distributed over the circumference in several support directions, in particular also on the opposite side of such a diameter line.

The latter is then usually carried out with the help of three contact points on the workpiece that are evenly distributed over the circumference or four opposite each other in pairs, which, however, prevents machining of the workpiece at the axial position of the support.

For the support, a bezel with prismatically arranged contact surfaces, which are formed in particular on separate support parts, is often used, which can therefore also be used for outer circumferences of different diameters.

In a system distributed over the circumference at four contact points, two opposing, often identical, prisms are often used.

With such steady rests that are supported over the entire circumference, a distinction must also be made between those that are driven synchronously and center the workpiece in the zero position, or on the axis of rotation in the case of a lathe, and those that are floating, i.e. the circumference to be supported as well in a position that deviates from the central position on the axis of rotation, for example.

Measuring the outer circumference, in particular the diameter, of the workpiece by means of separate measuring devices in the processing machine is known, but usually has the disadvantage that this measurement cannot usually be carried out during the machining of the workpiece, but rather during a separate measuring cycle processing time increased.

In principle, measuring the outer circumference using a supporting bezel is also known.

A diameter measurement with three contact points is, for example, from the DE 3719103 A1 known in that the then at least partially movable contact arms of such a bezel are detected in their support position by displacement sensors or position sensors and the diameter of the cylindrical workpiece at this point can be determined from this.

However, this only produces inaccurate measurement results, especially with movable support parts, since the joints that enable the movement and any additional link guides that may be present are subject to play, which increasingly distorts the measurement result.

With a bezel that includes a prism, it is made of the DE 10 2014 225 295 A1 already known, as a measuring device, to provide a measuring probe that can be extended relative to the prism along its bisector, which is moved until it rests on the outer circumference of the workpiece resting on the prism and in this way the diameter of the supported, cylindrical peripheral surface is determined.

With such solutions it is difficult or impossible to determine deviations in roundness of the supported circumference of the workpiece and/or to control the machining taking place in such a way that these deviations in roundness are avoided or reduced.

III. Presentation of the invention

a) Technical task

It is therefore the object according to the invention to provide a steady rest and a machine tool equipped with it, by means of which the outer circumference, in particular the diameter, of the workpiece at the support point can be measured in a simple manner as an in-process measurement especially its roundness deviations.

b) Solution to the task

This task is solved by the features of claims 1 and 13. Advantageous embodiments result from the subclaims.

A bezel of the generic type has a plurality of support bodies which are arranged at different circumferential positions of a Z-axis and, with only two support bodies, are arranged opposite one another and can thus be placed on the outer circumference of a workpiece extending in the Z direction between the support bodies.

The support bodies are motor-controlled and can be moved transversely to the Z-axis in one support direction along a bezel base; in the case of two support bodies lying opposite one another, the support directions are opposite to one another and define an X-axis of the bezel.

For this purpose, the support bodies each have a separate or a common support body drive.

Each of the support bodies has at least one contact surface, which is brought into contact with the outer circumference of the workpiece during operation of the bezel, namely at different circumferential positions of the workpiece, the circumferential positions being less than 180 ° apart, but preferably at the same Z position.

The workpiece can be supported, for example, by three support bodies, each of which has a contact surface, with adjacent contact surfaces each being arranged at an intermediate angle of less than 180° to one another.

However, the bezel preferably has only two support bodies, each of which has two prism-shaped contact surfaces arranged with an intermediate angle of less than 180° to one another.

The contact surfaces, in particular each individual contact surface, are preferably formed on a separate support part which is attached to one of the support bodies.

According to the invention, the existing object is achieved in that the bezel comprises a measuring device which is suitable for measuring the outer circumference, in particular the diameter (D) of a workpiece held clamped therebetween and/or for measuring the relative position, i.e. the mutual distances, the support bodies to each other and in particular the contact surfaces to each other.

If all contact surfaces rest on the outer circumference of a workpiece, i.e. the workpiece is thereby held clamped between the contact surfaces and the support bodies, the control can determine the outer circumference, in particular the diameter, of the workpiece, as is explained with reference to the drawings.

The support parts can be rotatable support rollers or just support plates, depending on whether a rolling or sliding contact is desired with respect to the workpiece, also depending on whether the workpiece rotates, in particular rotates quickly, in the state clamped in the bezel, or not. When rotating quickly, support rollers are therefore preferred.

In order to keep wear on the contact surfaces to a minimum, they often have a coating made of polycrystalline diamond (PCD) or cubic boron nitrite (CBN) or another extremely hard material.

If the support parts are support plates, their contact surfaces are preferably flat contact surfaces.

Unless otherwise stated, the following primarily explains the case of only two supporting bodies that are exactly opposite one another and movable in opposite supporting directions, each of which has two contact surfaces arranged at an angle, in particular at a right angle, in a prism shape to one another.

The two, preferably identical, support bodies are preferably arranged symmetrically to a plane of symmetry that is perpendicular to the support direction.

The two contact surfaces, in particular support parts, of a support body are preferably designed identically, regardless of their design, in order to keep the construction effort low, and are arranged in mirror image to a support plane which contains the support direction and runs in the Z direction.

For flat contact surfaces, the intermediate angle between the contact surfaces of the two support parts of a support body, i.e. in the prism, is preferably less than 120°, better less than 90°, better less than 80°, better less than 70°, better less than 60°.

By keeping the intermediate angle as small as possible, the translation between a change in the position of the support body in the support direction and an underlying change in the diameter of the workpiece becomes ever larger and the measurement result is therefore more precise.

• Im einfachsten Fall ist nur ein Stützkörper-Antrieb vorhanden und dieser wirkungsmäßig zwischen den, insbesondere beiden, Stützkörpern angeordnet und verändert direkt deren gegenseitigen Abstand.

The support body drive for the two support bodies can be designed and arranged differently:

• In the simplest case, only one support body drive is present and this is effectively arranged between the, in particular both, support bodies and directly changes their mutual distance.

A measuring device, which is preferably coupled to such a support body drive or is contained in it, can then directly measure the mutual distance, in particular between only two support bodies.

However - if the support bodies are mounted floating on the bezel base, for which the support body drive is designed to be non-self-locking in particular - it is not known whether the two support bodies are symmetrical to each other about the Z axis, i.e. the workpiece held by the bezel with its outer circumference lies centrally to the Z-axis or deviates from it in the

Another solution is that one, in particular one, support body drive is effectively arranged between the bezel base and one, in particular both, of the respective support bodies carried by it, and thus the respective support body is moved relative to the bezel base .

This can also be realized by a common support body drive, which is preferable to multiple support body drives for each support body, since the two support body drives would then have to be very well synchronized, since the two support bodies should preferably be able to be moved counter-synchronously.

A measuring device then present determines the relative position of the respective support body to the bezel base for each support body, and from these, in particular both, relative positions, an existing control of the bezel - knowing the position of the at least one contact surface on the respective support body - can Determine the distance between the two contact surfaces.

Preferably, a separate measuring device is then available for each support body, and in particular if there are two separate support body drives, the respective measuring device can be present on or in this support body drive, so that the synchronization of the two support body drives is also realized or at least monitored can be.

However, the measuring device can also have a separate, contact or non-contact measuring probe, which in particular is not identical to a contact surface, which - instead of measuring the position of the support body - determines the distance of the outer circumference of the workpiece from the measuring probe, for which the bezel does not rest on the workpiece must, but can be a concern. The measuring probe can be attached to the support body and/or the bezel base in a defined, known position.

Preferably, each support body has such a measuring probe, and the two measuring directions are identical, i.e. lie on the of the workpiece can be determined by the control, the diameter of the workpiece, in particular in the effective direction of the measuring probe, for example in the X direction.

The bezel can also include a force sensor or pressure sensor that measures the contact force or the pressure with which the contact surfaces rest on the workpiece.

Such a force sensor is preferably housed in the support body drive and can, for example, measure the current consumption of the electric motor of the support body drive.

This can ensure that when measuring, the contact force lies in a measuring force range intended for this purpose, and if not, the contact force can be varied so that it lies in a predetermined measuring force range, in particular corresponds to the predetermined measuring force.

The bezel can also include a temperature sensor, as temperature expansions of both the workpiece and the bezel can distort the measurement result.

The temperature sensor can measure the temperature of the peripheral surface of the workpiece at or near the point of contact with the contact surfaces, from which conclusions can be drawn about the existing temperature expansion of the workpiece.

The temperature sensor can also measure the temperature of the contact surface at or near the contact point, from which conclusions can be drawn about the temperature of the contact surface and consequently of the support body and thus the expansion of the bezel, but on the other hand also about the temperature expansion of the Workpiece can be closed.

The temperature sensor can also be arranged so that the temperature of the support body is measured, preferably at a distance from its contact surface, i.e. approximately in the middle between the contact surface and the bezel base or near the bezel base, from which the dimension and also the spatial Extension of the heating of the support body and thus its expansion can be closed.

The control must then of course be able to determine a correction value for the measured distance, in particular the actual diameter of the workpiece, from the determined temperatures and thus convert it for a specified target temperature, be it room temperature or one that will prevail later when the workpiece is in use Operating temperatur.

With regard to a machine tool that is used for material-removing machining of, in particular, wave-shaped workpieces, and comprises a steady rest, the object is achieved in that the steady rest is designed according to one of the preceding claims.

In addition, the steady rest base has guide shoes so that it can be moved in a controlled manner along guides in the machine tool that run in the Z direction.

This means that the steady rest can be placed in the Z position as close as possible to the current machining point of the workpiece and at every Z position on the workpiece.

With regard to the method for operating such a machine tool with such a steady rest, and in particular for measuring the circumference of the workpiece clamped by the steady rest, this task is solved in that the outer contour of the workpiece, which is clamped by the steady rest, is measured using the steady rest .

In the case of a circular circumferential contour, i.e. a cylindrical shape of the workpiece at the point of clamping by the bezel, the diameter of the workpiece can be determined at this point by measuring the mutual distance of the, in particular both, support bodies.

With only two, oppositely identical, support directions along the X-axis of the bezel, the diameter of the workpiece clamped between the support bodies is determined in the Workpiece cross-section can be moved.

• Werden die Stützkörper in X-Richtung gegeneinander vorgespannt bis zur Anlage am Werkstück mit einer vorgegebenen Anlage-Kraft (Kraft-gesteuert) unabhängig von der X-Position der beiden Stützkörper gegenüber der Lünetten-Basis, so passt sich die Lünette an die Position des Werkstück-Umfanges in X-Richtung an, auch wenn dieser exzentrisch zur Z-Achse, bei einer Drehmaschine oder Dreh-Fräsmaschine der Drehachse der Drehmaschine, befindet, also außermittig, liegt.

A distinction must be made between floating storage of the support bodies or the same positions of the support bodies in the support direction:

• If the support bodies are prestressed against each other in the X direction until they come into contact with the workpiece with a predetermined contact force (force-controlled) regardless of the -Circumference in the

The degree of eccentricity cannot then be measured unless the position of at least one of the two support bodies in the support direction relative to the bezel base is additionally determined, but not if only the mutual distance between the support bodies is determined.

If the X position relative to the bezel base is determined when the workpiece is clamped with only two opposing support bodies present, the diameter of the workpiece in the X direction at the clamping point can be determined from the comparison of these two X positions on the other hand, too the measure of the eccentric position to the Z axis in the X direction.

Through the control, this eccentricity can be taken into account for further processing or the support body shape force control can be switched to position control and the workpiece can thus be centered in the steady rest on the Z-axis before further processing.

If the support bodies are not floatingly attached to the bezel base, but are moved towards and away from one another in counter-synchrony with respect to the bezel base with respect to the Z-axis (position-controlled), then when the workpiece is clamped, it is additionally clamped using the Bezel centered on the Z axis or shifted there, at least in the X direction, at least when the contact surfaces are designed as a prism, but also in the Y direction, which is perpendicular to the X direction.

This is extremely useful for most machining operations, so that the machining point that is close in the Z direction can be machined on a centrally aligned workpiece - in the case of a crankshaft, at least from its main bearing points.

In addition, it is often of interest to determine whether there are unacceptably large deviations in roundness of the circumferential contour from the specified target contour, usually a cylindrical contour.

• Besteht die Rundheits-Abweichung darin, dass der Werkstück-Querschnitt statt eines Kreises eine leichte Ellipse bildet, so kann dies noch ermittelt werden.

With four contact points due to two opposing prism-shaped support bodies, not all types of roundness deviations can be determined due to the relative position of the support body to the workpiece:

• If the roundness deviation is that the workpiece cross-section forms a slight ellipse instead of a circle, this can still be determined.

If, on the other hand, the workpiece cross-section is modified to an approximately triangular shape, this can hardly be determined by the relative positions of the support bodies to the workpiece.

On the other hand, if the measuring device comprises - in addition to or instead of the previously described measuring device - a separate, non-contact or touching measuring probe on the bezel, which is not identical to a contact surface, which can be arranged in a known position on a support body or the bezel base, on at least one Circumferential location of the workpiece, preferably at two opposite locations, the radial position of the circumferential surface of the workpiece is measured.

Then, especially in the case of a CNC-controlled machine tool, for each rotational position of the workpiece, not only its circumferential contour but - if the measurement is carried out in a state not clamped by the steady rest - also its eccentricity with respect to the Z axis can be measured separately From this, a very precise actual circumferential contour can be determined using the control.

• So wird vorzugsweise zusätzlich die Kraft oder der Druck gemessen, mit der die Lünette mit ihren Anlageflächen am Werkstück anliegt.

Furthermore, other parameters are preferably measured using the bezel, which can influence the measurement result with regard to the diameter or eccentricity or the roundness deviation of the workpiece contour in the clamped area:

• The force or pressure with which the rest rests against the workpiece with its contact surfaces is preferably also measured.

Ideally, a measurement must always be carried out with the same measuring force in order to make the measurement results comparable. The measuring force during the measuring process must therefore generally be in a predetermined measuring force range, which can be checked using the force sensor or a pressure sensor, so that the contact force can also be changed accordingly if necessary.

• Es kann entweder die Temperatur des Werkstückes an der Kontaktstelle gegenüber der Lünette, vorzugsweise an allen Kontaktstellen, gemessen und daraus auf das Maß der Temperatur-Dehnung des Werkstückes selbst geschlossen werden.

Furthermore, the temperature present during the measurement can be measured, which can strongly influence the measurement result due to temperature expansion of both the workpiece and the bezel:

• Either the temperature of the workpiece at the contact point opposite the bezel, preferably at all contact points, can be measured and the measure of the temperature expansion of the workpiece itself can be determined from this.

The temperature of the bezel can also be determined, for example by measuring the temperature in the support part near the contact surface, and on the one hand the temperature of the opposite workpiece can be inferred, on the other hand the temperature of the support part and thus also the bezel is in the area of the support part known.

The temperature can also be measured away from the support part, for example approximately in the middle between the support part and the bezel base or close to the bezel base or both, from which the temperature of the support body itself, if necessary also the measure of their temperature expansion from the Contact area can be determined and thus the temperature expansion of the support bodies in the support direction can be concluded.

All of these measurements serve to modify inadequacies in the workpiece contour on the surface that has generally already been machined against which the steady rest rests, and in the machining process taking place in the next machining process, which is closely adjacent in the Z direction, so that these inadequacies are there occur less or not at all.

Just to clarify, it should also be noted for the method that if the two support bodies have a common support direction, this X direction of the steady rest can correspond to the and Z direction applies, whereby in the case of a workpiece driven in rotation by the machine tool during machining, the Z* axis of the machine tool is the axis of rotation around which the chuck, in particular the headstock, of the machine tool rotates.

c) Embodiments

• 1a: eine perspektivische Ansicht einer Werkzeugmaschine ohne Arbeitsraumabdeckung, mit einer Lünette,
• 1 b: eine andere perspektivische Ansicht der Werkzeugmaschine der 1a in einem nur teilweisen Aufbau,
• 1c: eine Zusatz-Spannvorrichtung in Form einer Lünette in perspektivischer Ansicht in Einzeldarstellung,
• 2a: eine Ansicht der Lünette aus 1c in Z-Richtung in Einzeldarstellung,
• 2b: eine Ausschnitt-Vergrößerung aus einer Frontansicht der Maschine, also lotrecht zur Z-Richtung genau von vorne, mit der Lünette,
• 3: eine Ansicht der Lünette aus 2a mit exzentrisch versetztem Werkstück,
• 4a, b: Ansichten der Lünette aus 2a mit einem Werkstück mit etwa elliptischem Querschnitt in zwei verschiedenen Drehlagen.

Embodiments according to the invention are described in more detail below by way of example. Show it:

• 1a : a perspective view of a machine tool without a workspace cover, with a bezel,
• 1 b : another perspective view of the machine tool 1a in an only partial structure,
• 1c : an additional clamping device in the form of a bezel in a perspective view in an individual representation,
• 2a : a view of the bezel 1c in the Z direction in individual representation,
• 2 B : an enlargement of a detail from a front view of the machine, i.e. perpendicular to the Z direction exactly from the front, with the bezel,
• 3 : a view of the bezel 2a with eccentrically offset workpiece,
• 4a, b : Views of the bezel 2a with a workpiece with an approximately elliptical cross section in two different rotational positions.

The bezel 100 according to the invention is shown using the example of a machine tool in the form of an internal circular milling machine, which is designed as an inclined bed machine.

The machine initially has a headstock 2 in the manner of a lathe, in which - see 2 B - one end of a workpiece W in the form of a shaft, preferably a crankshaft W, clamped and controlled and rotatable about the axis of rotation 10, which defines the Z direction, is accommodated in the workpiece spindle 2a of this headstock 2.

Spaced apart in the Z direction and opposite the headstock 2 with the workpiece spindle 2a, there is a counter-headstock 2', so that the chucks 8 on both sides are directed towards each other and can each clamp one of the ends of the workpiece W and drive it in a synchronous rotation.

The counter headstock 2 'can be moved in the Z direction on Z guides 9a, b, which run parallel to one another on the inclined mounting surface 1a of the inclined bed 1 in the X direction of the extension direction of this mounting surface.

The machine also has two tool supports 3a, b, each of which carries an internally toothed ring-shaped so-called internal milling cutter 5, which surrounds the workpiece W at an axial position during machining and processes its outer circumference, as in such internal cylindrical milling machines usually with a high speed of the internal milling cutter and a stationary or slowly rotating workpiece, especially the crankshaft.

The two tool supports 3a, b can be moved in the Z direction on a further pair of Z-guides 6a, b, which both lie within the two Z-guides 6a, b, on which the counter-headstock 2 'can be moved.

Each tool support 3a, b is constructed in the form of a portal, each with a Z-slide 4a or 4b, which - when viewed from above on the mounting surface 1a - has two side parts 4a1, 4b1, which extend from the front surface 4 'of the Z-slide 4a or b extend in the Z direction from the back of the respective Z-slide and run with their undersides on one of the Z-guides 6a, b, i.e. they are L-shaped.

The side parts are connected to one another at the upper end via a yoke 4a2, 4b2 to form a portal.

On the Z-slide 4a or 4b, a cross slide 7 can be moved in the Y direction, in that the annular internal milling cutter 5 is rotatably mounted and can be driven in a controlled manner, so that by moving the in its travel direction X ' - which is usually with the Extension direction X of the mounting surface 1a matches, but does not necessarily have to match - brought into contact with the outer circumference of the diameter of the workpiece W to be machined is, for example, the hub bearing of a crankshaft W tensioned on the main bearing axis of the machine.

The two tool supports 3a, b can be driven independently of one another by means of appropriate motors with regard to their movement in the X and Z directions and the drive of their internal milling cutters 5.

To stabilize the workpiece W during machining, it can - especially in the axial direction between the two tool supports 3a, b, as in the enlarged detail of 2 B can be seen - are clamped by an additional clamping device in the form of a bezel 100, preferably on a central, rotationally symmetrical surface of the workpiece W, i.e. on a main bearing point in the case of a crankshaft W.

• Die Lünette 100 umfasst zwei plattenförmige Stützkörper 102, 103, die lotrecht zur Z-Richtung der Lünette 100 und im eingebauten Zustand somit zur Drehachse 10 und vorzugsweise in Verfahr-Richtung X' der Maschine zueinander fluchtend und beabstandet zueinander liegen, sodass durch gegeneinander Fahren ihrer einander zugewandten Schmalseiten das Werkstück W dazwischen geklemmt werden kann.

Such a bezel is built into the machine 1 b and 2 B best recognized, and in the 1c and 2a reproduced individually:

• The bezel 100 comprises two plate-shaped support bodies 102, 103, which are aligned and spaced apart from one another perpendicular to the Z direction of the bezel 100 and, when installed, to the axis of rotation 10 and preferably in the travel direction The workpiece W can be clamped between the narrow sides facing each other.

As a rule, each of the support bodies 102, 103 can be moved in its support direction 102 'or 103' relative to a bezel base 101. In exceptional cases, one of the two support bodies is fixedly attached to the bezel base 101, which in turn is in the support direction of the other support body can be moved.

In the exemplary embodiment shown, the support directions 102 ', 103' are directed towards each other and define the X direction of the bezel 100.

In 2a A Z slide 100 Z of the bezel 100 serves as the bezel base 101, which can be experienced along longitudinal guides 16a, b in the Z direction within the machine.

In contrast, shows 1c a solution in which an X-slide 100X can be moved in the Parts of the workpiece W, such as the pin bearing journal of a crankshaft W, should serve.

Like best in 2a As can be seen, each of the narrow sides of the support body 102, 103 facing the other support body has a prism-shaped recess with two contact surfaces 102a'' located at right angles to one another and arranged symmetrically to a support plane 102'' or 103'', 102b'', 103a'', 103b'', which are each flat and are each formed on a separate support part 102a, b, 103a, b.

Appropriately approximated to each other in the supporting direction, these form a rectangle for contact surfaces, so that each of them rests on an exactly round outer circumference of a workpiece W, as shown, and holds it with a corresponding contact force.

In 2a Each of the support bodies 102, 103 can be moved in a controlled manner relative to the bezel base 101, be it by means of a separate support body drive 104.1, 104.2 or with - not shown - a common support body drive 104, which both support bodies 102, 103 are counter-synchronous at the same time, i.e drives in the respective support direction 102 ', 103'.

A corresponding measuring device 106 receives a position signal from the support body drives 104.1, 104.2 and can use this to determine the distance A between the support bodies 102, 103 and thus because of the known position of the contact surfaces 102a'', 102b'', 103a'' , 103b'' in these support bodies, calculate the mutual distance between the contact surfaces 102a'', 102b'', 103a'', 103b'' and from this calculate the diameter D which the workpiece W has on this, which is held clamped by the bezel 100, Z- Position has, provided it is a cylindrical peripheral surface.

In order to be able to correct the measured values, preferably each of the two support bodies 102, 103 can have a temperature sensor 108 with which - as shown in the left half of the picture - the temperature of the corresponding support part, e.g. 102a, in particular, in particular by touching it whose contact surface 102a'' can be determined or - as shown in the right half of the picture - the temperature of the opposite area of the circumference of the workpiece W can be measured without contact.

Likewise, a force or pressure sensor 105 can be present, either arranged on one of the support bodies 102, 103 or, as shown, assigned to one of the support body drives 104.1, 104.2, with which the contact force of the support bodies 102, 103 on the workpiece W is measured.

3 points in the same direction as 2a a design in which a support body drive is arranged directly between the two support bodies 102, 103 and the distance A between these two support bodies is adjusted, which can each be moved in a floating manner relative to the bezel base 101.

How 3 can be seen, the diameter D of the workpiece W can then be determined along the 100Z'' of the bezel 100, in contrast to the design of the 2a , in which the relative position of each of the two support bodies 102, 103 to the bezel base 101 is determined.

The 4a , 4b show with a design according to the bezel 2a that a deviation of the circumferential contour from a circular shape to an elliptical shape can also be determined by carrying out several measurements during 1 revolution of the workpiece W:

In 4a , in which the long transverse axis of the elliptical cross section at the clamping point through the bezel 100 is approximately aligned with its support directions 102 ', 103, i.e. the X direction, the measuring device 106 measures a larger distance A1, from which approximately the size of the long transverse axis can be determined compared to a larger distance A2 4b , if the short transverse axis of the elliptical cross section is aligned with the X direction.

If irregular, for example triangular, cross-sectional contours of the workpiece W are to be determined, this is not possible with the contact surfaces 102a", 102b", 103a", 103b" as sensing elements.

This would - in addition or instead - require a - preferably non-contact - measuring probe 107, as is arranged here on both support parts at the base of the prism with the viewing direction, i.e. measuring direction, towards the axis of rotation 10, i.e. the other support body.

Then - if the position of the measuring probe 107 is known - with a fixed arrangement on the corresponding support body, the position of the corresponding support body, relative to the bezel base 101, can be determined with only half a revolution - if there is only one measuring probe 107, a whole rotation - the entire circumference of the workpiece W can be scanned and its circumferential contour can be determined in terms of shape and size.

Alternatively, such a non-contact measuring probe 107 can also be arranged directly on the bezel base 101, for example in the gap between the two support bodies 102, 103, i.e. looking along the plane of symmetry 100Z '' in the direction of the axis of rotation 10 of the machine.

REFERENCE SYMBOL LIST

1

Bed

1a

Mounting surface

2

headstock

2'

Counter-headstock

2a

Workpiece spindle

3a, b

Tool support

4a, b

Portal carriage, Z carriage

4a1, 4b1

Side part

4a2, 4b2

yoke

5

Internal milling cutter

6a, b

first Z-guide

7

Cross slide

8th

chuck

9a, b

second Z guide

10

Rotary axis, Z direction

A, A1, A2

Distance

W

Workpiece, crankshaft

X

Extension direction of the mounting surface

X'

Travel direction

Y

second transverse direction, perpendicular to the travel direction X'

Z

Z direction, axis of rotation

100

Bezel

100X

X carriage

100Z

Z carriage

100Z''

plane of symmetry

101

Bezel base

102

Support body

102'

Direction of support

102''

Support level

103

Support body

103'

Direction of support

103''

Support level

102a, b,

Support part

103a, b

Support part

104

Support body drive

105

Force sensor

106

Measuring device

107

Measuring probe

108

Temperature sensor

W

workpiece

X, X*X-

Towards the steady rest or tool machine

Y, Y*y-

Towards the steady rest or tool machine

Z, Z* Z-

Towards the steady rest or tool machine

QUOTES INCLUDED IN THE DESCRIPTION

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Cited patent literature

• DE 3719103 A1 [0012]
• DE 102014225295 A1 [0014]

Claims (19)

Bezel (100) for supporting a, in particular wave-shaped, workpiece (W) transversely to its axial direction, the Z direction, with - several, in particular two support bodies (102, 103), - each of which has at least one, in particular two each , in particular only two, have contact surfaces (102a'', 102b'', 103a'', 103b''), with which they rest on the outer circumference of a contact point at different circumferential positions that are less than 180° apart At this point, a particularly cylindrical workpiece (W) can be brought, - the support bodies (102, 103) can be moved relative to one another or away from one another in a motor-controlled manner by means of a support body drive (104) along a bezel base (101), one in each case Support direction (102', 103'), characterized by - a measuring device (106) for measuring the relative position of the support bodies (102, 103), in particular their contact surfaces (102a'', 102b'', 103a'', 103b'' ), to each other, and / or for measuring the outer circumference, in particular the diameter (D) of a workpiece (W) held clamped between them. (roll or slide:) bezel Claim 1 , characterized in that - the contact surface (102a'', 102b'', 103a'', 103b'') are each formed on a support part (102a, b, 103a, b), - in particular the support parts (102a, b, 103a, b) are support rollers or support plates - which consist of polycrystalline diamond (PKD) or cubic boron nitrite (CBN), in particular on their contact surfaces (102a'', b'', 103a'', b''). Bezel according to one of the preceding claims, characterized in that - the contact surface (102a'', 102b'', 103a'', 103b'') are preferably flat and/or - the two support parts (102a, b, 103a, b ) of a support body (102, 103) are identical and are arranged in mirror image to a support plane (102'', 103'') which contains the support direction (102', 103'). Bezel according to one of the preceding claims, characterized in that - with only two support bodies which are arranged opposite one another, the support directions (102', 103') run opposite to one another. (Intermediate angle:) Bezel according to one of the preceding claims, characterized in that - for flat contact surfaces (102a'', 102b'', 103a'', 103b'') the intermediate angle (alpha) between them is smaller than 120°, better <90°, better < 80°, better <70°, better <60°, - at an intermediate angle of 90°, two opposing contact surfaces (102a'', 103a'' or 102b'', 103b'') of the two support bodies (102, 103) run parallel to each other. (Drive/measuring device:) Bezel according to one of the preceding claims, characterized in that with two supporting bodies arranged opposite one another - the supporting body drive (104) is effectively arranged between the two supporting bodies (102, 103) - in particular the measuring device (106) the distance (A) between the two support bodies (102, 103). Bezel according to one of the preceding claims, characterized in that - the at least one support body drive (104) is effectively arranged between the bezel base (101) and at least one of the two support bodies (2, 3), - in particular the measuring device (106 ) measures the relative position of the respective support body to the bezel base (101), - the control for the bezel (100) measures the distance (A) between the two support bodies (102, 103) from the two relative positions. (Separate measuring probe:) Bezel according to one of the preceding claims, characterized in that - the measuring device (106) comprises at least one non-contact or touching separate measuring probe (107), which is arranged in a defined position on the bezel base (101) or the support body (102, 103). and, in particular in the support direction (102', 103'), is directed against the peripheral surface of the workpiece (W) and measures its distance from the measuring probe (107), - in particular both supporting bodies (102, 103) have a measuring probe (107) exhibit. Bezel according to one of the preceding claims, characterized in that the support body drive (104) is not designed to be self-locking. (Force measurement:) Bezel according to one of the preceding claims, characterized in that - the bezel (100) comprises a force sensor (105) which measures the contact force or pressure with which the support body (102, 103), in particular its contact surfaces (102a'') , 102b'', 103a'', 103b''), (as) rests on the workpiece, measures, - the support body drive (104) is designed in such a way, that the contact force is adjustable, in particular constantly stable. (Temperature measurement:) Bezel according to one of the preceding claims, characterized in that the bezel (100) comprises a temperature sensor (108) which - the temperature of the contact surface (2a'', 2b'', 3a'', 3b'') of the support part (102, 103), in particular on or close to the adjacent workpiece (W) and/or - the temperature of the peripheral surface of the workpiece, in particular at or close to the contact point with the contact surface and/or - the temperature in the support body (102, 103) , in particular in the middle area between the contact surface and the bezel base (101), and - the control is able to measure the outer circumference, in particular the diameter, of the workpiece (W) at a predetermined target temperature, in particular, taking into account the determined temperature Room temperature or an operating temperature when the workpiece is in use (W). Machine tool for material-removing processing of, in particular wave-shaped, workpieces (W), - the machine tool having a steady rest (100) for supporting workpieces (W), characterized in that - the steady rest (100) is designed according to one of the preceding claims. Method for operating a machine tool, in particular for measuring the workpiece circumference of a workpiece (W), in particular a wave-shaped workpiece, clamped by the steady rest (100). Claim 12 , whereby in the case of two exactly opposite support directions (102', 103'), this is referred to as the in particular the machined outer contour, in particular the finished machined outer contour, of the workpiece circumference held by the steady rest (100) is measured. (Diameter:) Procedure according to Claim 13 , characterized in that - the mutual distance of the two support bodies (102, 103) in the support direction (102 ', 103'), in particular directly from one to the other support body (102, 103), is measured, - from this by the control of the actual -Diameter of the workpiece (W) clamped between the support bodies (102, 103) is determined. (Deviation from centric position:) Procedure according to Claim 13 or 14 , characterized in that - the position of each support body (102, 103) in the support direction (102 ', 103') is measured relative to the bezel base (101), - from this the actual diameter of the between the support bodies (102, 103) clamped workpiece and - in particular the deviation of this actual diameter from a concentric position around the zero position in the X direction, i.e. in a lathe the deviation from the axis of rotation in the X direction, is determined and - reported to the control - in particular the control takes this into account during the subsequent processing of the workpiece (W). (Roundness deviation:) Method according to one of the preceding method claims, characterized in that the roundness deviation of the outer diameter held by the bezel (100) is determined by, in the clamped state of the workpiece (W) - with defined rotational positions of the workpiece (W) about its Z axis Diameter of the workpiece (W) in the X direction and its deviation from the centric position in the ) is determined - in particular the control takes this into account during the subsequent processing of the workpiece (W). (Power:): Method according to one of the preceding method claims, characterized in that - the contact force on the workpiece (W) is measured during the distance measurement, in particular by means of a force sensor (105) or pressure sensor (105), which is in the support body (102, 103), in particular in the support part , is arranged as close as possible to the contact point, - either the contact force is set to a predetermined measuring force and / or - from this, knowing the rigidity of the support body (102, 103) from the control to the outer contour, in particular the diameter, at a predetermined Measuring force is closed. (Temperature:) Method according to one of the preceding method claims, characterized in that - the actual temperature of the workpiece (W) is measured, in particular by means of a temperature sensor (108), which is arranged in the support body (102, 103), in particular in the support part (102a, b, 103a, b), as close as possible to the Contact point - from this, knowing the expansion behavior of the material of the workpiece (W), the control determines the outer contour, in particular the diameter, at a predetermined target temperature. Method according to one of the preceding method claims, characterized in that - the temperature of the support body (102, 103) is determined, - a conclusion is drawn from this about its expansion in the of the diameter of the workpiece (W) in the X direction is corrected to a value at a specified target temperature.

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