EP3408053A1

EP3408053A1 - Method for machining workpieces and grinding machine

Info

Publication number: EP3408053A1
Application number: EP17701679.7A
Authority: EP
Inventors: Johannes Renz; Daniel Mavro; Joachim Ceruso; Wadim Karassik
Original assignee: Schaudt Mikrosa GmbH
Current assignee: Schaudt Mikrosa GmbH
Priority date: 2016-01-25
Filing date: 2017-01-23
Publication date: 2018-12-05
Also published as: DE102016101196B4; WO2017129513A1; US20180326552A1; CN109070300A; DE102016101196A1

Abstract

The invention relates to a grinding machine (10, 110) and to a method for machining workpieces (30) with wave-like shapes, in particular for grinding treatment, comprising the steps: receiving a workpiece (30) with a wave-like shape on a workpiece spindle (22); providing a group of steady rests (34, 36, 38, 40) which are spaced apart from one another along an axial longitudinal extension of the workpiece (30), wherein the steady rests (34, 36, 38, 40) can assume an engaged state and a non-engaged state, wherein the steady rests (34, 36, 38, 40) supportingly engage on the workpiece (30) in the engaged state; providing at least one grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) with at least one grinding tool (62, 64, 66, 68; 162, 164, 166, 168); and machining the workpiece (30), comprising: generating an infeed movement to bring the grinding tool (62, 64, 66, 68; 162, 164, 166, 168) into engagement with the workpiece (30); generating a relative rotation between the grinding tool (62, 64, 66, 68; 162, 164, 166, 168) and the workpiece (30); and controlling the group of steady rests (34, 36, 38, 40) to selectively transfer the steady rests (34, 36, 38, 40) into the engaged state or the non-engaged state.

Description

Process for machining workpieces and grinding machine

The present disclosure relates to a method for machining of corrugated workpieces, in particular a method for grinding shaft components for vehicle drives, such as rotor shafts, transmission shafts, camshafts, crankshafts or the like. The disclosure further relates to a machine tool, in particular a grinding machine, which is suitable for carrying out this method. Finally, the disclosure further relates to a machine control program for a machine tool, in particular for a grinding machine.

From DE 20 2010 004 788 U1 a Fräsbearbeitungszentrum for complete machining of workpieces is known, with a tool spindle and a machine control, wherein an adapter device is provided for deep hole drill, which can be releasably secured to the tool spindle, wherein the adapter means a base body and at least one base body associated with the bezel for supporting the deep hole drill, and a drive for moving the bezel along a feed axis of the tool spindle comprises. From DE 1 271 501 A a multi-spindle automatic lathe for individual workpieces is known, which are stretched between peaks and supported by a spindle drum, arranged on a support lunettes with rollers, the steady rests are radially adjustable in the direction of the workpiece for which purpose radially movable slides are provided, which are movable via cams.

From EP 0 788 419 B1 a device for deep rolling of Kehlungen in journal and main bearings of a crankshaft is known.

From US 5,103,596 A a control device for a cylindrical grinding machine is known, comprising a deflection suppression device comprising abutment elements comprising the cylindrical workpiece on both sides thereof, and a control unit connected to the deflection suppression device is connected to adjust a contact force of the contact elements.

From DE 38 14 038 A1 an external cylindrical grinding machine for crankshafts is known, which has an adjustable bezel for supporting the workpiece to be machined.

From EP 0 724 500 B1 a grinding machine with a worktable and a grinding wheel is known, with respect to which the worktable is displaceable, wherein the worktable carries a headstock with a tailstock adjustable with respect to this and an adjustable workpiece support, and wherein at least the headstock or the tailstock and in addition the workpiece support relative to the work table are adjustable.

From DE 10 201 1 102 1 13 A1 discloses a grinding machine for grinding external surfaces of a workpiece, in particular for external cylindrical grinding and / or external cylindrical grinding, known, with a workpiece holder, which is adapted to rotatably support a workpiece and / or controlled rotationally driven, with at least a first and a second set of grinding spindles, wherein the at least at least one first and second sets of grinding spindles are displaceable between a primary engaged position and a secondary engaged position, the first set of grinding spindles comprising at least a first primary grinding spindle and a first secondary grinding spindle, the second grinding spindle set comprising at least a second primary grinding spindle and a second secondary grinding spindle, at least the primary or secondary grinding spindle of the first and / or second grinding spindle set has a grinding wheel package which has a plurality of substantially rotationally symmetrical abrasive body surfaces which are graduated from one another and / or delimited from one another.

The known from DE 10 201 1 102 1 13 A1 grinding machine is particularly suitable for processing elongated wave-like workpieces. These include, for example, camshafts, transmission shafts, crankshafts, drive shafts or the like. According to at least some embodiments of DE 10 201 1 102 1 13 A1, the workpiece to be machined is receivable on a workpiece holder, which can also be referred to as a workpiece spindle. Furthermore, the grinding machine has a first spindle unit and a second spindle unit, which may, for example, each comprise a primary spindle and a secondary spindle. This has the advantage that without a re-tightening or retooling of the grinding machine different machining operations can be performed that require different processing tools (grinding wheel). This may include, for example, rough machining and finishing.

Another advantage of the known from DE 10 201 1 102 1 13 A1 grinding machine is that the two spindle units, which can also be referred to as spindle sets, face each other, currently used for machining grinding tools are facing each other and preferably have only a very small distance to each other. This allows, for example, the machining of shaft components with a pronounced longitudinal extension (large length-diameter ratio) without the need for a feed movement (in the longitudinal direction of the workpiece). Such machining can also be referred to as plunge grinding. In other words, the grinding tools may be designed so that they sufficiently reflect the desired contour of the workpiece. Accordingly, a Grinding tool may be referred to as a grinding wheel package. Such a grinding wheel package consists of a plurality of segments or sections, which may have a different shape from each other.

It is understood that grinding machines, especially cylindrical grinding machines, can also be designed otherwise. So it is not absolutely necessary to provide two grinding spindle sets. It is also conceivable to provide only one set of grinding spindles, on which a correspondingly designed grinding tool is received.

The present disclosure is particularly concerned with the machining of wave-shaped workpieces. This includes, for example, in the automotive field gear shafts, camshafts, crankshafts, drive shafts or the like. The wave-shaped workpieces do not necessarily have to be completely rotationally symmetrical. Rather, the workpieces may have eccentrically shaped sections, such as in the form of cams, cheeks or pins. In general, the workpieces have a large length to diameter ratio, which may be about 3: 1, 5: 1 or even 7: 1 or more. Reference diameter for this purpose may, for example, be a maximum diameter of the workpiece.

Furthermore, also the increasing use of electric motors as drives for electric vehicles, vehicles with fuel cells, and / or vehicles with hybrid drive for an increasing demand for high precision manufactured shaft components, such as rotor shafts.

Especially in mass production or mass production of components for drive technology, such as motors, electric motors, drive trains, valve trains, gearbox or the like, the shortest possible cycle times must be achieved. However, this must not be at the expense of accuracy or the required quality. Required accuracies and tolerances to be achieved are, for example, in the case of gear shafts in the range of a few μηη (microns). Cycle times of processing in the frame mass production or mass production for a gear shaft is well below 60 s (seconds).

A good compromise of the shortest possible cycle time and optimum accuracy can be achieved, for example, by a multi-stage machining method, which includes, for example, a pre-grinding and finish grinding of the workpiece, each with different grinding tools are used.

It has been shown that, although on the one hand with known grinders satisfactory results in terms of cycle time and machining accuracy can be achieved, but further optimization is desired. This applies in particular to the machining of corrugated workpieces with pronounced longitudinal extension.

Against this background, the disclosure has the object of specifying a method for machining workpieces, in particular a method for grinding workpieces, which allows a further optimization of the machining process and in particular given operating parameters, such as a given processing time, a further increase the accuracy allows. Preferably, the repeatability is improved, so that overall the process quality can increase. Furthermore, in the context of the present disclosure, a machine tool, in particular a grinding machine, is to be specified, which is designed to carry out the machining method. Preferably, the method can be used with little effort even in existing machine tools. Preferably, existing machine tools can be easily retrofitted or provided with control technology in order to allow execution of the method. It is another object of the present invention to provide a machine control program that enables a machine tool to perform the method.

The method concerning the object of the invention by a method for machining of wave-shaped workpieces, in particular for Grinding of shaft components for vehicle drives, rotor shafts, solved, comprising the following steps:

Receiving a wave-shaped workpiece on a workpiece spindle,

Providing a set of pegs spaced along an axial longitudinal extent of the workpiece, the pegs being capable of engaging an attack condition and a non-engagement condition, the pegs engaging the engagement member in a supporting condition,

Provision of at least one grinding spindle with at least one grinding tool, and

Machining the workpiece, comprising:

Generating a feed movement to bring the grinding tool into engagement with the workpiece,

- Generating a relative rotation between the grinding tool and the workpiece, and

- Actuation of the group of pegs to selectively put the pegs in the attack state or the non-attack state, wherein during processing, a change between the attack state and the non-attack state takes place.

The object of the invention is completely solved in this way.

According to the invention, namely, the method allows a selective attack or non-attack of the pegs to the workpiece. Switching between the attack state and the non-attack state occurs during machining of the workpiece, preferably multiple times. It has been found that in this way the machining accuracy and also the repeatability of the machining can be increased. In contrast to machining where the pegs permanently engage the workpiece, selective activation and deactivation of the pegs can contribute to increased manufacturing quality. This can be the case even if the other process parameters are not or only insignificantly changed. In other words, it has been found that an at least temporary relieving of at least one set of stock of the group of pegs can increase the achievable manufacturing accuracy.

Plinths as such are well known in the art. Buttocks are also called lunettes. In the context of this disclosure, buttocks generally mean support elements which are fixed directly or indirectly on the machine tool or grinding machine. Butt blocks are commonly used to support long or overlong workpieces during machining. On the one hand, this can apply to workpieces that are only clamped on one side. However, pegs are also used for workpieces that are accommodated on both sides, such as a workpiece spindle and a tailstock. Plinths counteract static deformations and dynamic deformations.

Obviously advantages and effects can stand out in particular in wave-shaped workpieces with pronounced longitudinal extent. This includes, for example, rotor shafts, transmission shafts, drive shafts, camshafts or crankshafts. The workpieces preferably have a length-diameter ratio of at least 3: 1, preferably at least 5: 1, more preferably at least 7: 1.

The pegs are designed in particular as active pegs and can attack in their attack state on the workpiece. This may include, for example, a defined contact force or holding force. In the non-attack state, the pegs can be lifted off the workpiece on the one hand. However, it is also conceivable that the contact force or driving force of the pegs in the non-attack state, compared to the attack state, is significantly reduced.

The method is suitable according to at least some embodiments in particular for machining by means of plunge grinding or Schrägeinstechschleifen, the grinding tool without axial feed (in the longitudinal direction) relative to the workpiece acts on this. Furthermore, the grinding tool is preferably as a segmen- designed tool and includes a plurality of portions associated with the peripheral portions of the workpiece. This includes embodiments in which a grinding tool or two grinding tools are engaged, which have a longitudinal extension corresponding to at least 30%, preferably at least 50%, more preferably at least 70% of the longitudinal extension of the workpiece.

During the machining process, at least one setter is alternately in the active state and in the inactive state, such as a rectangular function or a sine function. Accordingly, the states may be associated with discrete values or ranges of continuous values.

The method is suitable for the production of shaft components for vehicle drives, in particular of rotor shafts, transmission shafts, camshafts or crankshafts.

According to an exemplary embodiment of the method, the group of pegs on at least two individually controllable pegs, wherein during processing, at least temporarily a first peg is in the attack state, while a second peg is in the non-attack state, and wherein During processing, at least temporarily, the first set of stick is in the non-attack state while the second set is in the attack state.

In other words, two or more pegs are provided, which can be operated alternately or at least offset from each other in time. According to a further embodiment, the at least two setting sticks are operated alternately during the machining of the workpiece in the attack state and in the non-attack state. Thus, while the first setter is in the attack state, the second setter is at least temporarily in the non-attack state, and vice versa. This measure can contribute to further increase the manufacturing quality. According to a further embodiment of the method, the at least two pegs are at least temporarily in the same state when the first set of pegs from the attack state in the non-attack state and the second set of stick transferred from the non-attack state in the attack state becomes. In other words, there may be a temporal overlap of the states of the pegs. This can relate in particular to the attack state. However, according to alternative embodiments, this may also relate to the non-attack state.

According to this measure, it can be ensured that at least one setting stick is always in the attack state. This can prevent excessive bending of the workpiece, for example.

According to a further embodiment of the method, at least two pegs of the group of pegs are operated simultaneously in the attack state and in the non-attack state and switched back and forth between the attack state and the non-attack state. This may, for example, relate to a subset of the group of pegs. So it is conceivable that a total of four pegs are provided, of which two are operated simultaneously in the attack state and in the non-attack state. In each case two of the four pegs can therefore be controlled synchronously. According to an alternative embodiment, however, it is also conceivable that all of the pegs are operated simultaneously in the attack state and in the non-attack state.

The optimal control of the group of pegs can, depending on the application, be determined empirically or heuristically. It is conceivable, for example, to first define the duration and sequence of states for a setting stick or a group of setting sticks for a new application (a new type of workpiece) on the basis of empirical values. On the basis of such a basic state, optimizations can be carried out, in particular with regard to the production accuracy to be achieved or the reproducibility. Similarly, the timing or order of activation and deactivation of the individual setting sticks can be determined, cf. For illustrative purposes, for example, the firing order of the cylinders of an internal combustion engine. It has been shown that with a manageable effort based on a variation of the sequence of activation / deactivation or the duration of the respective states a significant optimization of the production result can be achieved.

However, it is also conceivable to vary the control of the group of setting sticks on the basis of stochastic or quasi-stochastic methods in order to select an optimum on the basis of a plurality of tests.

According to a further embodiment of the method, the setting sticks are further operable in a transient state, wherein the transient state describes an impending change between the attack state and the non-attack state. In this way, the transient state can be used to announce a change of state between the attack state and the non-attack state, and vice versa. In this way, the machine tool can be informed about the pending state change with a certain lead time. This can be used to at least temporarily adjust operating parameters to facilitate the transition between the attack state and the non-attack state.

According to a further embodiment of the method, the pegs act in the non-attack state with a reduced holding force on the workpiece. Alternatively, these pegs are lifted in the non-attack state of the workpiece. Conversely, the pegs act in the attack state in a defined manner on the workpiece. This can in particular include a defined holding force or contact force.

According to a further embodiment of the method, a feed force with which the grinding wheel acts on the workpiece, reduced when one of the pegs is switched between the attack state and the non-attack state. This can further increase the achievable accuracy. It is understood that the delivery force does not necessarily have to be reduced each time one of the pegs is changed between the attack state and the non-attack state. Nevertheless, it has been shown that it can be advantageous if the corresponding burden of the Workpiece, which is connected to the feed force, is reduced when at least one of the pegs is switched.

According to one embodiment of this embodiment, the delivery force is reduced, while the setter is in a transitional state, which initiates a change between the attack state and the non-attack state (and vice versa). In this way altogether a smooth transition between the attack state and the non-attack state can be made possible. The short-term reduction of the delivery force can relieve the workpiece and lead to a further increased quality.

It is understood that the delivery force does not necessarily have to be reduced to zero. Rather, embodiments are conceivable in which the delivery force, starting from a previous level (about 100%) is reduced to a reduced level (about 50%, 20% or 10%). The feed force is usually oriented perpendicular to the longitudinal axis of the workpiece. When Schrägeinstechschleifen deviations may result. The feed force can cause a deflection of the workpiece. In addition to the delivery force and the weight of the workpiece can cause a deflection. Furthermore, dynamic deformations during processing are conceivable. Usually, the pegs are designed to minimize unwanted workpiece deformations (such as deflection), which are generated by the workpiece itself (dead weight and dynamic effects during machining) or just by the tool (chip force of the grinding wheel or delivery force of the grinding wheel).

According to a further embodiment of the method, at least some pegs of the group of pegs are switched back and forth several times during the processing between the attack state and the non-attack state, preferably at least two pegs of the group of pegs alternately between the attack state and switch back to the non-attack state. A signal curve of the activity of a setting stick resulting from the change between the attack state and the non-attack state can in principle comprise a binary course, ie assume exactly two discrete values which are connected to one another by steep edges. However, it is also conceivable that the change between the attack state and the non-attack state causes a waveform that is designed approximately sinusoidal. This is especially true when the setter is operable in addition to the attack state and the non-attack state in the transition state. The states themselves do not necessarily have to be assigned a discrete, constant value. Rather, a state, such as a sinusoidal signal, a certain range of values of the signal include (about attack state: 90% to 70%, transition state: 70% to 30%, non-attack state: 30% to 0%). It is understood that other designs and intermediates are conceivable.

Overall, there may be a state period that includes the attack state and the non-attack state and, if present, the transition state. The duration of such a period may be, for example, values of 0.5 s (seconds) up to 2 s, 5 s or even more.

In principle, the duration of the non-attack state can correspond to the duration of the attack state. However, embodiments are conceivable in which the duration of the attack state is greater than the duration of the non-attack state.

The grinding machine achieves the object of the invention by a grinding machine, in particular a cylindrical grinding machine, which has the following:

- a machine bed,

a workpiece holder with a workpiece spindle,

at least one grinding spindle with a grinding tool,

a set of pegs spaced apart from each other, the pegs being operable in an attack state and a non-attack state, and the pegs being configured to be engaged in engagement with each other; stood supporting a workpiece, which is received on the workpiece holder, and

- A control device which is adapted to put the setting sticks selectively during the machining of the workpiece in the attack state and the non-attack state, with a defined change between the attack state and the non-attack state.

Also in this way the object of the invention is completely solved.

Preferably, the grinding machine is designed for plunge grinding or Schrägeinstechschleifen. This may include embodiments in which the machining of the workpiece does not include a feed movement along the longitudinal axis of the workpiece.

Preferably, the grinding machine is suitable for carrying out the machining method according to at least one of the aspects described here. The group of pegs may comprise about 2, 3, 4 or even more pegs, which are spaced apart along the longitudinal extent of the workpiece, directly or indirectly received on the machine bed.

According to one embodiment of the grinding machine, the control device is further adapted to control a feed drive of the grinding spindle to reduce a feed force of the grinding wheel on the workpiece during a transition of a setting stick between the attack state and the non-attack state.

According to a further embodiment of the grinding machine, the setting sticks and the grinding spindle are arranged on opposite sides of the received workpiece, wherein the setting sticks, in particular in the attack state, provide a force of force opposing the delivery force on the workpiece acts. In this way, a bending of the workpiece due to the delivery forces can be effectively counteracted.

According to a further embodiment of the grinding machine, at least some setting sticks of the group of setting sticks are designed as active setting sticks and provided with at least one set stock drive or can be coupled in order to put a respective set stick optionally in the attack state or the non-attack state.

By way of example, active setting sticks can comprise gripping arms and the like, which can be displaced at least in sections in order to effect the change of state. The Setzstockantrieb can be designed as a hydraulic drive or pneumatic drive. It is also conceivable to design the Setzstockantrieb as electrical, magnetic or electromechanical drive.

According to a further embodiment of the grinding machine, the control device is further adapted to put the setting sticks in a transitional state, which is traversed at a change between the attack state and the non-attack state, wherein the grinding spindle is controlled defined during the transition state , in particular to control the feed force of the grinding wheel on the workpiece.

For purposes of illustration, reference will be made to a traffic light comprising a red, a green and a yellow signal. The attack state corresponds to the green signal by way of example. The non-assault state corresponds to the red signal accordingly. The transition state corresponds to the yellow signal, which announces the change between the green signal and the red signal (and vice versa). In other words, a structural change does not necessarily have to result during the transitional state at the setting stick itself or at its butt drive. Rather, the transition state heralds the imminent transition between the attack state and the non-attack state. According to a further embodiment of the grinding machine, the at least one grinding spindle carries at least one grinding wheel designed as a grinding wheel package, wherein the grinding wheel package has a core which is designed in several parts and has different axial sections which are joined together, and wherein the grinding wheel package a plurality of Having abrasive segments, which are associated with corresponding sections of the workpiece to be machined. The core can be designed at least in sections as a composite body, in particular as a fiber composite body.

Such designed grinding wheel packages allow grinding wheels with a large axial extent, which can thus handle large axial sections of a workpiece simultaneously. It has been found that, in particular, when the workpiece is machined simultaneously in a piercing process at several sections, the selective actuation of the setting sticks for the transition between the attack state and the non-attack state leads to a significant improvement in accuracy.

It is conceivable that the grinding wheel designed as a grinding wheel package has a longitudinal extent, which corresponds substantially to the longitudinal extension of the workpiece. Accordingly, the workpiece can basically be worked on all or almost all of its circumference.

According to a further embodiment of the grinding machine a plurality of spindle units are provided, in particular two spindle units, wherein at least one of the spindle units has a grinding spindle with a cantilevered grinding wheel, and wherein the spindle units are preferably accommodated facing each other on the machine bed. The spindle units can generally also be described as spindle sets. The spindle units may each comprise one or more grinding spindles. The flying support of the grinding wheel makes it possible to arrange two spindle units, which are arranged facing one another on the machine bed, in such a way that the grinding wheels are very close. Accordingly, the workpiece can be processed simultaneously with both grinding wheels, with a considerable portion of the

Longitudinal extension of the workpiece can be edited. According to a further embodiment of the grinding machine, at least one spindle unit is provided, which comprises two grinding spindles, wherein the two grinding spindles have a common traversing drive, and wherein the two grinding spindles of the spindle unit mutually in an active position or a passive position with respect to the workpiece are movable, in particular by a pivot drive, which is associated with the spindle unit.

Accordingly, with only one spindle unit comprising two grinding spindles, rough machining and fine machining can be performed. In general, the combination of several processing steps is conceivable that require different grinding tools.

By way of example, the grinding machine is designed such that two spindle units are provided, each comprising two grinding spindles, wherein the grinding spindles of the spindle units have cantilevered grinding wheels. Each of the spindle units may include a pivot drive to selectively engage one of the two grinding wheels in engagement with the workpiece. The mentioned configuration allows a complete machining or almost complete machining of the workpiece in only one clamping. Preferably, this can be done by means of plunge grinding or Schrägeinstechschleifen without a feed movement along the longitudinal axis of the workpiece is required.

The object underlying the disclosure is further solved by a machine control program having program code adapted to cause a control device of a machine tool to execute the steps of the method according to one of the aspects mentioned herein when the machine control program is executed on the control device becomes.

It is understood that the features of the invention to be explained below and those to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention. Further features and advantages of the invention will become apparent from the following description of several preferred embodiments with reference to the drawings. Show it:

Fig. 1 is a simplified perspective view of an embodiment of a

Grinding machine with a buttstock arrangement;

Figure 2 is a simplified perspective view of an alternative embodiment of a grinding machine with a jig assembly.

3 shows a schematic, highly simplified plan view of an arrangement comprising a workpiece, a group of setting sticks and two grinding tools which can be controlled via a control device;

4 is a partial perspective view of a grinding machine for illustrating an exemplary embodiment of a setting stick;

FIG. 5 is a state diagram illustrating a state history of a group of pegs; FIG.

6 shows a state diagram for illustrating a state progression of a group of setting sticks, the course of the illustration according to FIG. 6 deviating from the course according to FIG. 5; FIG.

7 is a state diagram for illustrating the state history of a

Group of pegs, wherein for illustration further a state of a feed drive is shown;

8 shows a further state diagram for the temporal comparison of various states that a first setter and a second setter can assume;

9 is a schematic block diagram for illustrating an embodiment of a method for grinding workpieces; and

10 is a schematic block diagram illustrating partial steps of an embodiment of a method for grinding workpieces.

Fig. 1 shows a schematic perspective view of a machine tool 10, which is designed as a grinding machine. The grinding machine 10 has a machine bed 12, which may also be referred to as a frame. On the machine bed 12 guides 16, 18 are formed. Along the guides 16, 18 components of the grinding machine 10 can be moved and optionally set.

In at least some of the figures shown here, a coordinate system is shown by way of illustration. Generally, a longitudinal direction is designated by X. A transverse direction is designated Z. A vertical direction is designated Y. In this way three translational axes X, Y and Z are defined. A respective rotation about the axes X, Y, Z defines a corresponding axis of rotation. It is understood that for purposes of description, alternative coordinate systems, such as machine coordinate systems and / or workpiece coordinate systems, are conceivable. The required intellectual transformation is readily possible for the person skilled in the art.

It is understood that terms used in the context of this disclosure such as first element, second element, primary element, secondary element are used primarily for the purposes of distinction and in particular do not relate to qualitative weighting.

The grinding machine 10 further includes a workpiece holder 20, which is taken for example on the guide 16. The workpiece holder 20 includes a workpiece spindle 22. The workpiece spindle 22 may include a drive to selectively drive a picked tool. By way of example, the workpiece holder 20 comprises a first workpiece holder 24 and a second workpiece holder 26, between which a workpiece 30 is received. The first workpiece holder 24 may comprise a clamping device for the workpiece 30. The second workpiece holder 26 is exemplified as a tailstock. The workpiece spindle 22 may further include a C-axis drive 28 that permits defined rotation of the workpiece 30 about its longitudinal axis. The longitudinal axis of the workpiece 30 is parallel to the X-axis. The C-axis drive 28 allows a defined Dregehrichtung of the workpiece 30. This allows about the machining of eccentric contours of the workpiece 30. In this way, about cams or the like can be ground. The workpiece 30 is about a camshaft, a transmission shaft, a drive shaft or a crankshaft. The workpiece 30 has a pronounced longitudinal extent. In this respect, the workpiece 30 may also be referred to as an elongated workpiece. The workpiece 30 is designed like a wave. In the exemplary embodiment according to FIG. 1, the workpiece 30 is accommodated on both sides of the workpiece holder 20, namely between the first workpiece holder 24 and the second workpiece holder 26. It is also conceivable to receive the workpiece 30 on one side only, ie approximately to the second workpiece holder 26 dispense, which is designed as a tailstock.

The workpiece 30 can also be a rotor shaft of a

Electric motor act. In particular, this is a drive motor for a vehicle. Due to the increasing spread of vehicles with alternative drives, such as electric vehicles, hybrid vehicles and the like., Also increases the distribution of such components. The workpiece 30 may also be generally referred to as a shaft member for a vehicle drive

Workpieces 30, which are designed as a transmission shaft, crankshaft, camshaft or drive shaft, often have a pronounced longitudinal extent. This includes a high aspect ratio, such as a length to diameter ratio of the workpiece 30 of at least 3: 1, at least 5: 1, or at least 7: 1. Such long workpieces 30 are often taken on both sides of the workpiece holder 20. Furthermore, a support of the workpiece 30 along a

Longitudinal extent done by a Setzstockanordnung 32, which includes approximately a first set of stick 34 and a second set of stick 36.

The pegs 34, 36 are configured to supportively engage the workpiece 30 to counteract deformation or bending of the workpiece 30. Preferably, the pegs 34, 36 are designed as active pegs. This includes embodiments in which the setting sticks 34, 36 are provided with drives to selectively provide the setting sticks 34, 36 in an attack state or a non-attack state. Thus, at least according to some embodiments, there is no permanent support by the pegs 34, 36. Rather, the pegs 34, 36 are temporarily activated and temporarily deactivated to increase the accuracy of the grinding process. This may include a simultaneous actuation of the pegs 34, 36. Furthermore, this may include a mutual actuation of the pegs 34, 36. The pegs 34, 36 can be activated in phase or out of phase. An in-phase activation is present when several pegs 34, 36 are both in the attack state or in the non-attack state at the same time. A phase-shifted or out-of-phase activation occurs when at least temporarily one butt in the attack state and another buttstock is simultaneously in the non-attack state.

Embodiments of the present disclosure are concerned with the driving of buttocks assemblies 32 that include a plurality of jacks 34, 36. This will be explained in more detail below.

The actual (material-removing) processing in the grinding machine 10 is performed by spindle units 50, 52, which may also be referred to as spindle sets. The grinding machine 10 has at least one spindle unit 50, 52. According to the exemplary embodiment illustrated with reference to FIG. 1, the grinding machine 10 comprises a first spindle unit 50 and a second spindle unit 52. The spindle units 50, 52 each comprise at least one headstock.

The first spindle unit 50 comprises a primary grinding spindle 54 and a secondary grinding spindle 56. The second spindle unit 52 comprises a primary grinding spindle 58 and a secondary grinding spindle 60. A grinding tool 62 is received on the grinding spindle 54. On the grinding spindle 56, a grinding tool 64 is added. On the grinding spindle 58, a grinding tool 66 is added. On the grinding spindle 60, a grinding tool 68 is added.

The grinding tools 62, 64, 66, 68 are preferably designed as grinding wheels. At least some of the grinding tools 62, 64, 66, 68 are designed, for example, as grinding disk packages and comprise a plurality of segments, which are approximately different. ne diameter may have. The grinding tools 62, 64, 66, 68 are usually rotationally symmetrical, at least on their working surfaces.

The spindle units 50, 52 are designed such that the grinding tools 62, 64, 66, 68 of the spindle units 50, 52 used for the machining respectively face each other. This includes an exemplary embodiment in which the grinding tools 62, 64, 66, 68 are each received in a flying manner on the grinding spindle 54, 56, 58, 60 associated therewith.

The spindle unit 50 is received on a table 72. The spindle unit 52 is received on a table 74. The table 72 may be referred to as the first table. The table 74 may also be referred to as a second table. The first table 72 has a guide base 76 and a carriage 78. The second table 74 has a guide base 80 and a carriage 82. The tables 72, 74 are exemplarily added to the guide 18 on the machine bed moved. In this way, movement in the X direction parallel to the longitudinal extension of the workpiece 30 can be effected. The guide base 76, 80 and the carriages 78, 82 of the tables 72, 74 may be movable relative to each other. This allows movement along the Z axis. This movement is also referred to as a feed movement or puncture movement. The tables 72, 74 may also be referred to as cross tables or cross slides.

The first spindle unit 50 further comprises a pivot drive 86 which defines a pivot axis 90. The spindle unit 52 comprises a pivot drive 88, which comprises a pivot axis 92. The pivot drive 86 may also be referred to as the first pivot drive. The pivot drive 88 may also be referred to as a second pivot drive. In Fig. 1, the pivot axes 90, 92 of the pivot drives 86, 88 are oriented parallel to the longitudinal axis of the workpiece 30 and to the X-axis.

The tables 72, 74 and their associated rotary actuators 86, 88 can be used to selectively lock the primary grinding spindle 54, 58 or the secondary To bring grinding spindle 56, 60 into engagement with the workpiece 30. By way of example, the primary grinding spindles 54, 58 with their associated grinding tools 62, 66 can be used for a first processing stage. Accordingly, the secondary spindles 56, 60 with their associated grinding tools 64, 68 can be used for a second processing stage. The various processing stages may include, for example, the processing of various portions of the workpiece 30. However, the various processing stages may include rough machining and finishing.

Further indicated in FIG. 1 is a control device, designated 96, which serves to control functions and machining processes of the grinding machine 10. This includes, in particular, a control of travel drives, spindle drives and an activation of the setter assembly 32.

Fig. 2 illustrates a simplified perspective view of a modified embodiment of a grinding machine 1 10. The grinding machine 1 10 of the illustrated with reference to FIG. 1 grinding machine 10 is at least similar, so that will be given priority to modified components and features. It is understood that assemblies, modules and functions of the grinding machines 10, 1 10 according to Figures 1 and 2 combined with each other and / or transferable from one of the two grinding machines 10, 1 10 to the other.

The grinding machine 1 10 is similar to the grinding machine 10 of FIG. 1 provided with a Setzstockanordnung 32. The butting arrangement 32 of the grinding machine 1 10 comprises by way of example four setting sticks 34, 36, 38, 40. Such a design is basically conceivable even in the grinding machine 10 according to FIG. The pegs 34, 36, 38, 40 are taken for example on the guide 16. The pegs 34, 36, 38, 40 are axially spaced apart along the longitudinal extent of the workpiece 30 and are coupled directly or indirectly to the machine bed 12.

The grinding machine 110 is further provided with a first spindle unit 150 comprising a first grinding spindle set. There is also a second spin deleinheit 152 provided, which includes a second set of grinding spindles. The first spindle unit 150 is associated with a primary grinding spindle 154 and a secondary grinding spindle 156. The second spindle unit 152 is associated with a primary grinding spindle 158 and a secondary grinding spindle 160.

The primary grinding spindle 154 of the first spindle unit 150 carries a grinding tool 162. The secondary grinding spindle 156 of the first spindle unit 150 carries a grinding tool 164. The primary grinding spindle 158 of the second spindle unit 152 carries a grinding tool 166. The secondary grinding spindle 160 of the second spindle unit 152 carries a grinding tool 168. The grinding tools 162, 164, 166, 168 of the spindle units 150, 152 are cantilevered. This makes it possible to bring the currently used for machining grinding tools 162, 164, 166, 168 very close to each other in order to edit the workpiece 30 as large as possible can.

The grinding spindles 154, 156, 158, 160 of each spindle unit 150, 152 are arranged facing away from each other. The grinding spindles 154, 156, 158, 160 assigned to the respective spindle unit 150, 152 can be aligned concentrically with one another. However, a parallel offset between the grinding spindles 154, 156, 158, 160 on the respective spindle unit 150, 152 is also conceivable.

The spindle unit 150 is received on a table 172 which includes a guide base 176 and a carriage 178. The spindle unit 152 is received on a table 174 which includes a guide base 180 and a carriage 182. The tables 172, 174, permit movement of the spindle units 150, 152 with the grinding spindles 154, 156, 158, 160 received thereon in a plane which is spanned by the axes X and Z.

The first spindle unit 150 further includes a pivot drive 186 which defines a pivot axis 190. The second spindle unit 152 further includes a pivot drive 188 defining a pivot axis 192. The pivot axes 190, 192 are oriented parallel to the Y-axis. The pivot axes 190, 192 may also be referred to as so-called. B-axes. The part-turn actuators 186, 188 allow on the one hand a selective activation or deactivation of the primary grinding spindles 154, 156 or the secondary grinding spindles 156, 160. In addition, the pivoting drives 186, 188 can also be used to make the grinding tools 162, 164, 166, 168 obliquely opposite the workpiece 30. In other words, in such a position, the longitudinal axes of the workpiece 30 and the grinding tool 162, 164, 166, 168 may have a defined offset angle to each other. In this way, approximately conical sections of the workpiece 30 can be processed.

In Fig. 2, the first spindle unit 150 is shown in an intermediate state, which is approximately at a change between the primary grinding spindle 154 and the secondary grinding spindle 156.

With regard to the basic structural design of the machine tool 10 according to FIG. 1 and the machine tool 1 10 according to FIG. 2, reference is again explicitly made to DE 10 201 1 102 1 13 A1.

Fig. 3 shows in a highly simplified schematic representation a plan view of a workpiece 30 which is received between a first workpiece holder 24 and a second workpiece holder 26 to be processed by grinding tools 62, 66. Further, in Fig. 3, a Setzstockanordnung 32 indicated, the four pegs 34, 36, 38, 40 comprises.

The grinding tools 62, 66 are designed by way of example as grinding wheel packages. For example, the grinding tool 62 includes various segments 200, 202, 204, which are designed differently. The grinding tools 62-68, 162-168 described in the context of this disclosure may in particular be so-called built grinding wheel packages comprising a core (carrier core) on which segments 200, 202, 204 are received. The core can be designed in one piece or in several parts, cf. also DE 10 201 1 102 1 13 A1. In this way, on the one hand, a sufficiently stiff grinding wheel can be provided. Furthermore, the grinding wheel package is weight optimized and has only a low inertia. In addition, the design allows as a grinding wheel package in wear or in In the event of a defect, replacement of only one of the segments 200, 202, 204. In this respect, further cost advantages may result during operation.

The segments 200, 202, 204 are adapted to corresponding peripheral portions 206, 208, 210 of the workpiece 30. Accordingly, the grinding tools 62, 66 are designed primarily for plunge grinding. In other words, during machining, there is no relative movement along the X direction (longitudinal direction of the workpiece 30) between the workpiece 30 and the grinding tools 62, 66.

In Fig. 3, block arrows designated 212, 214 illustrate advancing or advancing drive of the grinding tools 62, 66 toward the workpiece 30. Feed is along the Z axis (feed axis). It is understood that the feed can also take place along an axis which is inclined relative to the Z-axis. This is done especially in the so-called. Schrägeinstechschleifen.

At least some of the jacks 34, 36, 38, 40 of the jig assembly 32 include a holding portion 218, a drive 220, and an interface 222 for coupling to the controller 96. The holding portion 218 may include, for example, retaining arms, gripping arms, jaws, or the like , Preferably, the holding portion 218 is configured to receive the workpiece 30 circumferentially at two or three defined points. The drive 220 is preferably configured to act on at least one element of the holding portion 218. In this way, the setter can 34, 36, 38, 40 are lifted from the workpiece 30. Alternatively, it is conceivable that a holding force or biasing force with which the setter 34, 36, 38, 40 acts on the workpiece 30 is significantly reduced. In this way, the buttocks 34, 36, 38, 40 can be shifted from an attack state to a non-attack state, and vice versa.

The controller 96 is preferably coupled to the buttstock assembly 32 and to the feed drives 212, 214. In this way, about a feed force with which the grinding tools 62-68, 162-168 act on the workpiece 30 to a current state of the pegs 34, 36, 38, 40 of the Setzstockanord- be adapted. Thus, it is conceivable to reduce the feed force at least briefly when a state change of at least one of the setting sticks 34, 36, 38, 40 is performed.

FIG. 3 further illustrates that the pegs 34, 36, 38, 40 of the buttstock assembly 32 are preferably disposed on a side of the workpiece 30 that faces the abrasive tools 62-68, 162-168. In this way, the pegs 34, 36, 38, 40, the feed force of the grinding tools 62-68, 162-168 record or counteract.

FIG. 4 illustrates a partial view of a grinding machine having a butt 34 engaging a workpiece 30 received on a workpiece holder 20. The setter 34 has a base 226 which is received on a guide 16 on the machine bed 12 of the grinding machine. The base 226 carries a drive 220 and an interface 222. The drive 220 of the setting stick 34 may be designed approximately as a fluidic drive or as an electromechanical drive.

The setter 34 has a holding portion 218. The holding portion 218 of the setting stick 34 includes, for example, a first arm 228 and a second arm 230 that receive a portion of the workpiece 30 therebetween. The arms 228, 230 may also be referred to as holding arms, gripping arms or as clamping jaws. The drive 220 is configured to selectively open or close the arms 228, 230. A corresponding movement of the arms 228, 230 is illustrated in Fig. 4 by 232, 234 designated double arrows. The closed position corresponds to the attack state. The open position corresponds to the non-attack state. Alternatively, the drive 220 may be configured to control and selectively alter the biasing force of the arms 228, 230 with respect to the workpiece 30.

In this way, the setting stick 34 can be controlled in a defined manner via the control device 96 (see FIG. 3) in order to support the workpiece 30 in a state of attack as well as in a non-attack state from the workpiece 30 be removed or at least with a significantly reduced holding force to the workpiece 30 attack.

The buttress 34 shown in Fig. 4 may also be referred to as an active setter. The active buttstock 34 can be operated via the control device 96 during machining of the workpiece 30 at least in the attack state and in the non-attack state.

Fig. 5 illustrates a temporal state history of a jig assembly comprising four jigs according to the jig assembly 32 illustrated with reference to Fig. 3, for example. A horizontal axis (abscissa) illustrates the time course (t). The diagram shown in FIG. 5 further comprises signal waveforms labeled 238, 240, 242, 244. The waveform 238 is associated with a first set of pegs. The waveform 240 is associated with a second setter. The waveform 242 is associated with a third setter. The waveform 244 is associated with a fourth setter. The waveforms 238, 240, 242, 244 each include two states labeled I and II. State I describes, by way of example, the non-contact state of the respective setting stick. State II exemplifies the attack state.

Overall, Fig. 5 shows that the pegs can be driven offset in time according to one embodiment, so that a phase shift between the waveforms 238, 240, 242, 244 occurs. Accordingly, there is a waveform in which always at least one of the pegs is in the attack state. It is understood that the frequency or length of the states I and II shown here need not necessarily be constant. Deviating designs are conceivable, for example, depending on the actual machining task.

Fig. 6 illustrates an alternative embodiment of a signal waveform for driving a Setzstockanordnung. Signals denoted by 248, 250, 252, 254 may be assigned to a total of four setting sticks. In Fig. 6, the signal run phase synchronized. Accordingly, all pegs are simultaneously in the attack state or in the non-attack state.

It is understood that a mixture of the signal curves illustrated with reference to FIGS. 5 and 6 is readily conceivable, in which approximately individual pairs of the group of setting sticks are driven out of phase with respect to other setting sticks (FIG. 5), the setting sticks of FIG Couples with each other in phase synchronous (Fig. 6) are controlled.

As already explained above, it is provided according to an exemplary embodiment, to coordinate the activation of the setting sticks with the control of the feed drives of the grinding tools or to synchronize. In this way, about a feed force acting on the workpiece, can be reduced when a state change or status change occurs in one of the setting sticks.

In this context, reference is also made to Fig. 7, which illustrates a temporal state course of two setting sticks and these a state history of the delivery force descriptive signal is compared. A signal labeled 258 is associated with a first jig. A signal labeled 260 is associated with a second setter. A designated 262 signal describes the course of the delivery force. As previously described, the waveforms 258, 260 associated with the sticks may describe an attack condition and a non-engagement condition.

FIG. 7 further illustrates a transition state by inclined flanks 264, 266. Flanks designated 264 describe a transition state when changing from non-attack state I to attack state II. Flanks designated 266 designate a transition state when changing from the attack state II to the non-attack state I. In the illustration of FIG the first set of sticks from the Attack state to the Non-Attack state from the non-Attack state to the Attack state. However, this is only to be understood as an exemplary embodiment. Fig. 7 further shows that the feed force is reduced when a state change is pending at one of the setting sticks. The relationship illustrated in FIG. 7 between setting stance state and feed force can in principle also be provided in the case of the signal curves illustrated with reference to FIG. 5 and FIG. 6.

For reasons of illustration, in FIG. 7 the feed force indicated by the signal curve 262 is only described qualitatively, wherein a first state is designated by I and a second state by II. By way of example, the state I can describe a reduced delivery force. This also includes a state where the feed force is zero. State II describes, by way of example, a maximum delivery force. It is understood that the change between the states I and II does not have to be abrupt with infinitely steep flanks. Rather, the delivery force at

Change between the states I and II pass through a transition area. Furthermore, it is understood that the signal curves illustrated in FIGS. 5 to 7 for the actuation of the setting sticks as a whole can have a smoothed course. The states I and II do not necessarily have to be assigned discrete values (such as open or not open). Accordingly, the state curves may also include, for example, sinusoidal or similarly smoothed curves. The same generally applies to the signal curve of the delivery force.

Fig. 8 illustrates in a modified representation of the various states that can take the pegs. By way of example, a block labeled 268 describes a first set of sticks and a block labeled 270 describes a second set of sticks. The pegs can occupy a total of three states, designated 272, 276 and 274. State 272 exemplifies the non-attack state. State 274 exemplifies the attack state. State 276 describes a transient state. At the transition between state 272 and state 274, a setter moves through the transient state. The transition state can be used to announce the actual state change of the peg. In this way, a time window is created that allows an adjustment of the feed force. For comparison, reference is made to a traffic light in traffic. The transition state corresponds to the yellow signal, the one Transition between the red signal and the green signal (and vice versa) signals.

The transition state 276 can also be used if the states 272, 276 are actually to be understood as discrete states. Even if the buttstock - structurally, based on the attack on the workpiece - can assume only two states (such as OPEN and CLOSE), the transition state allows improved flexibility and a higher variety of functions in the control. In FIG. 8, the two waveforms indicated by 268, 270 are mutually in the attack state and in the non-attack state, respectively, wherein during the change between the states, the transition state is simultaneously passed through.

It is understood that the flowcharts illustrated in FIGS. 5 to 8 are merely examples. Based on the basic configurations illustrated by way of example, a target configuration can be derived by heuristic measures if, for example, the order, frequency or a phase offset of the signal profiles are varied. The temporal portion of the states in a period can also be varied. It is further understood that a periodically recurring sequence of states does not necessarily have to be present. Rather, depending on the current application, deviations from a strictly periodic sequence may be made.

FIG. 9 illustrates a method for processing workpieces, in particular for grinding rotor shafts, transmission shafts, camshafts, drive shafts or crankshafts, on the basis of a schematically highly simplified block diagram. These can also be commonly referred to as shaft components for vehicle drives.

The method comprises a step S10, in which a wave-shaped workpiece is received on a workpiece spindle. The workpiece does not necessarily have to be completely rotationally symmetrical. It is also conceivable workpieces that have cams or similar eccentrically shaped contours. A step S12 comprises the provision of a group of pegs which are arranged spaced apart along an axial longitudinal extent of the workpiece. The buttocks are preferably active pegs that can assume an attack state and a non-attack state. In the attack state, the pegs supportively engage the workpiece to prevent excessive deformations, deflections or the like. In the non-attack state, the pegs are exemplary spaced from the workpiece. Alternatively, at least one holding force or supporting force with which the setting sticks engage the workpiece is reduced in the non-attack state. The setting sticks are preferably coupled to a control device of the grinding machine, which is designed to selectively control individual setting sticks or at least part sets of setting sticks.

Another step S14 relates to the provision of at least one grinding spindle, which is provided with at least one grinding tool, in particular a grinding wheel. Preferably, the grinding spindle with the grinding tool received thereon is configured for plunge grinding or for oblique plunge grinding.

This is followed by a further step S16, which includes the machining of the workpiece. Step S16 may include substeps S18, S20, S22. The step S18 includes generating a feed motion to bring the grinding tool into engagement with the workpiece. The step S20 comprises generating a relative rotation between the grinding tool and the workpiece, whereby the actual material-removing machining is made possible. The relative rotation between the grinding tool and the workpiece can be effected by activating a grinding spindle and / or by activating a workpiece spindle.

Another sub-step S22 of the processing step S16 relates to a control of the group of pegs, wherein at least some pegs of the group of pegs are selectively placed in the attack state or the non-attack state. This takes place during the machining of the workpiece. This selective control of the pegs during machining can lead to higher manufacturing accuracy. 10 illustrates, by way of a schematically highly simplified block diagram, an exemplary embodiment of a method for driving a group of setting sticks during a machining, in particular an abrasive machining, of a workpiece.

The method comprises a step S50, which basically can be based on the processing step S16 illustrated in FIG. 9. Step S50 comprises various sub-steps S52-S66 which relate, for example, to the actuation of a first setting stick (steps S52, S58, S64), a second setting stick (S54, S60, S66) and a feed drive (S56, S62).

During machining, while at least one grinding tool engages the workpiece, the setting sticks can be operated alternately in the attack state and in the non-attack state. It is understood that periods of time are conceivable in which both pegs are simultaneously in the attack state or in the non-attack state. By way of example, sub-steps S52 and S54 describe a state in which the first set stick in the non-attack state and the second set stick in the attack state. A change of state of the setting sticks can be initiated via a so-called transition state. During the transient state, sub-step S56 may be followed, which includes, by way of example, a reduction in the feed force. Then the actual (structural) change of state of the pegs can take place. Accordingly, the sub-step S56 may further include increasing the feed force again. Subsequent steps S58, S60 describe a period in which, for example, the first set of pegs is in the attack state and the second peg is in the non-attack state.

Again, a transitional state can follow, which is used, for example, first to reduce the feed force, to bring about the actual (structural) change of state of the setting sticks, and then to raise the feed force again, cf. the sub-step S62. Again, a period may follow, in which the pegs are operated in their new states, cf. sub-steps S64 and S66, wherein the first set of stick in the non-attack state and the second set-up stick is in the attack state. It will be understood that the state histories exemplified and described herein are the starting point of many conceivable procedures. It is essential that a plurality of setting sticks is provided, at least some of which are selectively controllable in order to operate the setting sticks alternately in an attack state and a non-attack state during the processing of the workpiece. Thus, there are active and passive phases for at least one of the pegs. Depending on a currently machined workpiece, in particular its geometry and the selected material, optimizations can be carried out, for example, by means of heuristic and / or empirical methods.

Claims

claims

Method for machining wave-shaped workpieces (30), in particular for grinding shaft components for vehicle drives, comprising the following steps:

Receiving a wave-shaped workpiece (30) on a workpiece spindle (22),

Providing a set of pegs (34, 36, 38, 40) spaced along an axial longitudinal extent of the workpiece (30), the pegs (34, 36, 38, 40) in an attack condition and a non-engagement condition can take, wherein the setting sticks (34, 36, 38, 40) in the attack state supporting the workpiece (30) attack,

Providing at least one grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) with at least one grinding tool (62, 64, 66, 68; 162, 164, 166, 168) and machining the workpiece (30) , full:

- generating a feed movement to the grinding tool (62, 64, 66, 68;

162, 164, 166, 168) into engagement with the workpiece (30),

- Generating a relative rotation between the grinding tool (62, 64, 66, 68, 162, 164, 166, 168) and the workpiece (30), and

Activating the group of setting sticks (34, 36, 38, 40) to selectively set the setting sticks (34, 36, 38, 40) in the attacking state or in the inoperative state, during which processing Change takes place between the attack state and the non-attack state.

Method according to claim 1, wherein the group of setting sticks (34, 36, 38, 40) has at least two individually controllable setting sticks (34, 36, 38, 40), during machining at least at times a first setting stick (34) in the attack state while a second buttstock (36) is in the non-assault state, and wherein during processing, at least temporarily, the first buttstock (34) is in the non-assault state while the second buttstock (36) is in the assault state located.

3. The method of claim 2, wherein the at least two setting sticks (34, 36, 38, 40) during machining of the workpiece (30) are mutually operated in the attack state and in the non-attack state.

4. The method of claim 2 or 3, wherein the at least two pegs (34, 36, 38, 40) are at least temporarily in the same state when the first set of stick (34) from the attack state in the non-attack state and the second setter (36) is transferred from the non-attack state to the attack state.

5. The method of claim 2, wherein at least two sets (34, 36, 38, 40) of the set of blocks are operated simultaneously in the attack state and in the non-attack state, and between the attack state and the non-attack state be switched back and forth.

The method of any one of the preceding claims, wherein the pegs (34, 36, 38, 40) are further operable in a transient state, the transient condition describing an impending change between the attack condition and the non-engagement condition.

A method according to any one of the preceding claims, wherein a feed force with which the grinding tool (62, 64, 66, 68; 162, 164, 166, 168) acts on the workpiece (30) is reduced when one of the pegs ( 34, 36, 38, 40) is switched between the attack state and the non-attack state, wherein the feed force is preferably reduced, while the set stick (34, 36, 38, 40) is in a transitional state, a change between the attack state and the non-attack state initiates.

8. The method according to any one of the preceding claims, wherein at least some pegs (34, 36, 38, 40) of the group of pegs during processing several times between the attack state and the non-attack state are switched back and forth, preferably at least two Pegs (34, 36, 38, 40) of the group of pegs are alternately switched back and forth between the attack state and the non-attack state.

9. The method according to any one of the preceding claims, wherein the workpiece (30) is designed as a rotor shaft, gear shaft, camshaft or crankshaft.

10. A grinding machine (10, 10) comprising:

a machine bed (12),

a workpiece holder (20) with a workpiece spindle (22),

at least one grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) having a grinding tool (62, 64, 66, 68; 162, 164, 166, 168),

a set of pegs (34, 36, 38, 40) spaced apart from each other, the pegs (34, 36, 38, 40) being operable in an attack state and a non-engagement state, and the pegs ( 34, 36, 38, 40) are adapted, in the engaged state, to engage in support of a workpiece (30) which is received on the workpiece holder (20), and a control device (96) which is adapted to position the setting sticks (34, 34). 36, 38, 40) during machining of the workpiece (30) selectively in the attack state or the non-attack state, with a defined change between the attack state and the non-attack state.

1 1. The grinding machine (10, 110) of claim 10, wherein the control means (96) is further adapted to control a feed drive of the grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) to during a transition a setting stick (34, 36, 38, 40) between the attack state and the non-attack state to reduce a feed force of the grinding tool (62, 64, 66, 68; 162, 164, 166, 168) on the workpiece (30) ,

12. grinding machine (10, 1 10) according to claim 10 or 1 1, wherein at least some of the pegs (34, 36, 38, 40) of the group of pegs are designed as active pegs and provided with at least one butt drive (220) kop kop or - pelbar to selectively place a respective set stick (34, 36, 38, 40) in the attack state or the non-attack state.

13. Grinding machine (10, 1 10) according to any one of claims 10 to 2, wherein the control device (96) is further adapted to put the setting sticks (34, 36, 38, 40) in a transitional state, which in a change between the attack state and the non-attack state, wherein during the transition state, the grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) is driven in a defined manner, in particular by the feed force of the grinding tool (62, 64, 66, 68, 162, 164, 166, 168) to the workpiece (30).

14. grinding machine (10, 1 10) according to any one of claims 10 to 13, wherein the at least one grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) at least one designed as a grinding wheel package grinding wheel (62, 64, 66, 68, 162, 164, 166, 168), wherein the grinding wheel package has a core that is multi-piece and has various axial portions joined together, and wherein the grinding wheel package comprises a plurality of abrasive segments (200, 202, 204 ) associated with corresponding portions (206, 208, 210) of the workpiece (30) to be machined.

15. Grinding machine (10, 1 10) according to one of claims 10 to 14, further comprising at least one of the following configurations:

a plurality of spindle units (50, 52; 150, 152), in particular two spindle units, wherein at least one of the spindle units (50, 52; 150, 152) has a grinding spindle (54, 56, 58, 60; 154, 156, 158, 160) a floating grinding wheel (62, 64, 66, 68; 162, 164, 166, 168), and wherein the spindle units (50, 52; 150, 152) are preferably received facing each other on the machine bed (12), and

at least one spindle unit (50, 52; 150, 152) comprising two grinding spindles (54, 56, 58, 60; 154, 156, 158, 160), the two grinding spindles (54, 56, 58, 60; 156, 158, 160) have a common travel drive (86, 88, 186, 188), and wherein the two grinding spindles (54, 56, 58, 60; 154, 156, 158, 160) the spindle unit (50, 52; 150, 152) are mutually movable to an active position or a passive position with respect to the workpiece (30).

16. Grinding machine (10, 1 10) according to claim 15, wherein the common travel drive is a pivot drive (86, 88, 186, 188) which is associated with the spindle unit (50, 52, 150, 152).

17. grinding machine (10, 1 10) according to any one of claims 9 to 16, wherein the grinding machine (10, 1 10) is designed as a cylindrical grinding machine.

A machine control program comprising program code adapted to cause a control device (96) of a machine tool (10) to perform the steps of the method of any one of claims 1 to 9 when the machine control program is executed on the control device (96) ,