EP3310530B1 - Method and grinding machine for grinding external and internal contours of workpieces in one set-up - Google Patents

Description

The invention relates to a method for grinding a workpiece with external and internal contours to be ground in one setting, and a grinding machine of the type of a universal cylindrical grinding machine and/or non-circular machine for carrying out the method.

Out of DE 10 2007 009 843 B4 is already known to grind both the outer contour and the inner contour of a workpiece. On the one hand, several clamping states are required so that internal grinding can even be carried out on separate machines after external grinding has taken place. On the other hand, grinding the inner contour requires supporting by means of a steady rest after a steady rest seat has been ground beforehand. This known grinding method and the grinding machine known to implement this grinding method are relatively complex and have limitations in terms of the accuracy that can be achieved due to the fact that the workpiece has to be brought into different clamping states so that all grinding processes on the workpiece can be ground.

In EP 0559 935 A1 a method for grinding a machine component that is driven to rotate about its longitudinal axis in one setting is known. The machine component is clamped axially at both ends and has an inner recess to be ground, which is machined using an inner grinding wheel. On the internal cavity side, a component for clamping and centering a workpiece is used, which is in the form of a ring with a flange, part of the ring being in the form of a truncated cone. This part is clamped against the work piece to be machined and serves to hold it in place during grinding, with the internal grinding wheel passing through the inside of the ring for engagement with the work piece. The machine component is held in a single clamping between the workpiece headstock and the tailstock, driven in rotation, and ground by means of at least one grinding wheel on its outer contour and by means of the inner grinding wheel on its inner recess. The clamping on the work headstock is carried out with a center point engaging in the face of the machine component.

In contrast, the object of the present invention is to provide a grinding method and a grinding machine with which workpieces can be ground with high accuracy both on their outer contour and on their inner contour, while maintaining the centered clamping during grinding.

This object is achieved by a method having the features of claim 1 and by a grinding machine having the features of claim 13. Expedient developments are defined in the respective dependent claims.

The method according to the invention for grinding a machine component, which is driven to rotate about its longitudinal axis, takes place in one and the same clamping. The machine component is preferably a gear shaft or a gear wheel. The machine component is clamped at its two axial ends with respect to the longitudinal axis of the machine component and has an internal recess at least at one end. The inner recess is ground using an inner grinding wheel, which is preferably also referred to as an inner grinding pin. When clamped, the machine component is held in a rotationally driven manner between a work headstock and a tailstock, with the outer contour of the machine component being ground by means of at least one grinding wheel. The machine component is thus held centered on one side by means of the workhead and on the opposite side on the tailstock with a tailstock hollow sleeve at the end area of the inner recess pointing outwards towards the end of the machine component. The tailstock hollow quill makes it possible to reach through the internal grinding wheel while grinding the internal recess. Since the tailstock hollow quill preferably engages in the inner recess of the machine component with a revolving hollow center and the machine component is also held centered on the opposite side in the workhead, the machine component can be ground both inside and outside and, if necessary, also on its front sides in a single clamping . Because the grinding takes place in one clamping, there is no reference change for the various grinding processes that are implemented with different grinding wheels. As a result, the grinding accuracy for the machine component can be further increased. Above all, all outer contours as well as the inner contours are on one and the same centering, i. H. the longitudinal axis of rotation of the machine component. This also further minimizes concentricity errors.

Due to the fact that the tailstock has a tailstock hollow sleeve with a hollow point and preferably also a hollow point on the workhead - if the machine component has an inner recess at each end - through which the respective inner grinding wheel can reach, it is preferably possible that the external grinding and the internal grinding are carried out at least temporarily at the same time. This also has a cost-saving effect because it reduces the cycle time in the manufacture of the machine component.

The reference axis for the machine component, ie its longitudinal axis of rotation, is preferably retained unchanged during the grinding operation, because this coincides with the centering taking place at both ends of the machine component. Especially with components of normal length and normal rigidity, a steady rest support is not required. In a grinding machine according to the prior art referred to in the introduction to the description DE 10 2007 009 843 B4 On the other hand, it is necessary to provide a steady seat for external grinding, on which after completion of this seat a steady can be moved to the corresponding point of the machine component, so that the machine component migrates as little as possible from its previously specified centering of the clamping. Internal grinding of the recess present on the end faces or on the end face of the machine component can only be carried out after the steady rest has been supported. According to the present invention, "without steady rest support" should be understood to mean that a steady rest for the purpose of making the inner recess accessible in order to be able to grind it is no longer required because, according to the prior art, the clamping on the tailstock had to be released. It goes without saying, however, that in the case of particularly long components, steady rests can certainly be provided, namely distributed over the length of the component in such a way that during processing of the outer contour and the associated grinding forces introduced, deformation of the machine component with respect to its longitudinal axis is prevented or minimized. For the purpose of grinding the inner recess, however, a special steady rest support is not required due to the existing hollow points or hollow quills.

So that the machine component can also be effectively centered on the workhead, the workhead is equipped either with a centrically clamping chuck or with a chuck with compensating jaws and a centering point that engages in the face of the machine component. However, it is also possible that in the event that the machine component also has an internal recess on the side of the workhead, the workhead has a workhead hollow sleeve with a hollow point, so that from this side through the workhead, which is then hollow, the Internal grinding wheel can grind the internal recess without having to loosen the clamping during grinding or for the purpose of internal grinding.

According to a preferred embodiment, the internal grinding wheel with its spindle and the grinding wheel for external grinding are also with their spindle on a common one Arranged headstock and are brought by pivoting and / or method in particular steplessly engaged with the machine component or disengaged from it. The respective spindles of the respective grinding wheels can be moved in a direction parallel to the longitudinal axis of the machine component by means of a pivotable arrangement on a carriage for grinding the inner recess and for grinding the outer contour.

According to a further exemplary embodiment of the invention, the grinding wheel for external grinding is arranged on a grinding headstock, which is then pivoted and/or moved towards the workpiece in order to bring this grinding wheel into engagement during external grinding. In addition, the internal grinding wheel is arranged on a separate grinding headstock, preferably in the area of the tailstock, and can be moved relative to the longitudinal axis of the workpiece in such a way that the internal grinding wheel, which is also referred to as an internal grinding pin, engages through the tailstock hollow quill with hollow point in the longitudinal direction of the machine component and the inner recess thus grinds. This ensures that the grinding of the outer contour of the machine component and the inner surface of the inner recess can be carried out at least temporarily at the same time.

According to another development, when grinding the outer contour of the machine component, the axis of rotation of the grinding wheel for external grinding and the common axis of rotation of the work headstock, machine component and tailstock are arranged at an oblique angle to one another in space such that during grinding there is essentially only point contact between the grinding wheel and the outer contour of the machine component is present. The longitudinal feed then preferably takes place in the direction of the workhead. Arranging the axes at an oblique angle to one another, which ensures point contact between the grinding wheel and the outer contour of the machine component, is also referred to as Quickpoint grinding.

However, it is preferably also possible that when grinding the outer contour of the machine component, the axis of rotation of the grinding wheel and the common axis of rotation of the work headstock, machine component and tailstock run parallel or at an angle to one another in the same plane, so that there is essentially linear contact between the grinding wheel and the outer contour of the machine component is guaranteed. This is advantageous when a longitudinal feed of the grinding wheel is not required for straight or oblique plunge-cut grinding when grinding the outer contour of the machine component. If the outer contour of the machine component is profiled, straight or angled plunge grinding can also be carried out with a profiled grinding wheel, which of course can and must be dressed like all other grinding wheels in the meantime.

Preferably, it is also possible for the grinding wheel for external grinding to grind both peripheral areas, preferably of a rotationally symmetrical type, and end faces of the machine component.

The tailstock hollow quill is preferably designed to run along; however, it can also be driven. The drive of the tailstock hollow quill is preferably coordinated with the drive of the work headstock on the opposite side in the sense of an electronic shaft.

The grinding of the machine component is preferably carried out using CNC controls. This means that all movements of the machine component or the grinding tools are CNC-controlled.

According to a second aspect of the invention, a grinding machine of the type of a universal cylindrical grinding machine and/or non-cylindrical grinding machine is provided for carrying out the method described above. In the usual way, the grinding machine has a grinding table on which a work headstock and a tailstock are arranged, which can be moved in the longitudinal direction of the grinding table. A machine component to be ground can be clamped between the workhead and the tailstock in such a way that the common longitudinal axis of the workhead, machine component and tailstock runs in the longitudinal direction of the grinding table.

However, it is also possible for the grinding table to be fixed with respect to the machine bed and for the grinding headstock or grinding headstocks to be movable parallel along the common longitudinal axis of the work headstock, machine component and tailstock.

The workhead has either a centrically clamping chuck or a chuck with compensating, detachable clamping jaws and a center point, which holds the machine component on the workhead in a rotationally driving manner. Both types of chuck ensure centering when clamping the machine component on the workhead. The tailstock has a tailstock hollow quill with a preferably traveling hollow point in the manner of an engaging pin engaging in a chamfer of the inner recess. This hollow point engages in the inner recess of the machine component in such a way that a centering engagement is ensured, specifically in such a way that this centering engagement is adapted to a rotationally symmetrical inner recess at least at the end of the machine component which can be clamped on the tailstock, ie on the end opposite the workhead.

The tailstock hollow quill and the hollow center have an internal bore which is large enough for the internal grinding wheel to grind the internal recess, i. H. the inner surface of the inner recess, the inner bore of the hollow sleeve and the hollow point can penetrate. The internal grinding wheel can now be arranged with its internal grinding spindle either on the grinding headstock, which can be swiveled and moved in such a way that the internal grinding wheel can reach through the inner bore of the tailstock hollow quill and grind the inner recess accordingly. The disadvantage of such an arrangement is that external grinding and internal grinding have to be carried out one after the other. For further optimization of the grinding process on the grinding machine according to the invention, above all in terms of time and costs, it is preferably also provided that a separate wheelhead headstock is arranged in the area of the tailstock and carries the internal grinding wheel with its internal grinding spindle. The infeed of the internal grinding wheel in the passage of the tailstock hollow quill then takes place essentially in the direction of the longitudinal axis of the machine component, so that the inner peripheral surface of the inner recess can be ground, at least temporarily at the same time as grinding the outer contour of the machine component. The grinding machine according to the invention preferably has both a swiveling grinding headstock, also with a grinding spindle carrying an internal grinding wheel, and the separate grinding headstock as an additional grinding headstock.

In the grinding machine according to the invention, the workpiece headstock and the tailstock can be moved relative to one another in such a way that the machine component is held and rotationally driven between the centering point on the workpiece headstock or the centrically clamping chuck provided there and the hollow center on the tailstock under axial pressure and with a reference axis that cannot be changed during clamping. The grinding machine according to the invention therefore enables external grinding and internal grinding to take place at least temporarily in parallel. Since the grinding on the grinding machine according to the invention takes place in one and the same clamping, the reference axis is not changed during the grinding, whereby a higher accuracy of the machine components ground with the grinding machine according to the invention is achieved.

A carriage is preferably provided which can be moved in a controlled manner perpendicular to the longitudinal direction of the grinding table and on which a grinding headstock which can be pivoted about a vertical pivot axis is arranged. The grinding wheel, which is driven to rotate, is mounted on this wheelhead for grinding the outer contour of the machine component with this in Grinding intervention can be brought, the grinding wheel for grinding the outer contour being mounted on the grinding headstock with the axis of rotation running horizontally.

The grinding wheel preferably has a grinding layer both on its circumference and on its end face. This makes it possible to use the grinding machine according to the invention to grind cylindrical outer contours as well as planar surfaces or cones on the machine component, if necessary even by means of plunge-cut grinding, without the clamping having to be released.

The inner grinding wheel and the grinding wheel for the outer contour are preferably each provided with a CBN coating. The CBN coating ensures high grinding accuracy, high grinding removal and yet a long service life for the grinding wheels.

If the machine component also has an internal recess on the side of the workhead clamping the machine component, then the chuck is preferably of hollow design, so that this hollow bore of the chuck can also reach through this internal recess at the end of the machine component on the workpiece headstock side by means of a further internal grinding wheel for grinding. This additional internal grinding wheel is preferably arranged on an additional, separate internal grinding headstock, so that this additional internal grinding wheel can be moved and infed independently of the grinding headstock for the outer contour. Even with internal recesses at both ends of the machine component, a time-parallel grinding of both the outer contour and the inner contours can be realized with the grinding machine according to the invention.

Figur 1:

Eine erfindungsgemäße Schleifmaschine in Draufsicht;

Figur 2:

eine im Grundaufbau Figur 1 entsprechende Schleifmaschine, jedoch mit zusätzlichem Innenschleifspindelstock;

Figur 3:

eine Teilansicht der erfindungsgemäßen Schleifmaschine mit zum Außenschleifen des Maschinenbauteils eingeschwenkter Schleifspindel mit Außenschleifscheibe;

Figur 4:

eine Teilansicht einer Schleifmaschine mit eingeschwenkter Schleifspindel mit Innenschleifscheibe;

Figur 5:

Detailansicht des im Werkstückspindelstock mit Spannfutter gespannten Maschinenbauteils sowie Spannung mit Reitstock-Hohlpinole bei Innenschleifscheibe außer Eingriff;

Figur 6:

eine Detailansicht gemäß Figur 5 bei Innenschleifscheibe im Eingriff mit der Innenausnehmung des Maschinenbauteils;

Figur 7:

eine prinzipielle Draufsicht einer erfindungsgemäßen Schleifmaschine mit zwei Schleifspindelstöcken;

Figur 8:

eine Detailansicht der erfindungsgemäßen Schleifmaschine mit zwei Innenschleifspindeln für beidseitig vorgesehene Innenausnehmungen am Maschinenbauteil; und

Figur 9:

eine prinzipielle Anordnung eines Maschinenbauteils in Form eines Zahnrades, welches gemäß dem Verfahren der Erfindung geschliffen wird.

Further configurations and details of the present invention will now be explained in detail with reference to the attached drawing. Show in the drawing:

Figure 1:

A grinding machine according to the invention in plan view;

Figure 2:

one in the basic structure figure 1 Corresponding grinding machine, but with additional internal grinding headstock;

Figure 3:

a partial view of the grinding machine according to the invention with the grinding spindle pivoted in for external grinding of the machine component with an external grinding wheel;

Figure 4:

a partial view of a grinding machine with a swiveled-in grinding spindle with an internal grinding wheel;

Figure 5:

Detailed view of the machine component clamped in the work headstock with a chuck and clamping with the tailstock hollow quill with the internal grinding wheel disengaged;

Figure 6:

a detailed view according to figure 5 in the case of an internal grinding wheel in engagement with the inner recess of the machine component;

Figure 7:

a basic plan view of a grinding machine according to the invention with two grinding headstocks;

Figure 8:

a detailed view of the grinding machine according to the invention with two internal grinding spindles for internal recesses provided on both sides of the machine component; and

Figure 9:

a basic arrangement of a machine component in the form of a gear, which is ground according to the method of the invention.

In the 1 The basic structure of the grinding machine shown in plan view is based on the structure of a universal cylindrical and/or non-cylindrical grinding machine. A grinding table 28 provided in the usual manner is guided in a longitudinally displaceable manner on a machine bed 27 in the direction of a so-called Z-axis. On the grinding table 28 a work headstock 9 with its (not designated) drive motor and a chuck 11 is attached. The chuck 11 serves to clamp the workpiece, ie the machine component 2. The machine component is clamped on the work headstock 9 by means of a center point 13 and detachable clamping jaws 12 of the chuck 11.

A tailstock 10 is arranged coaxially with the workhead 9 at an axial distance therefrom. The tailstock 10 has a separately designed sleeve for receiving a tailstock center designed as a hollow tailstock sleeve 15 . The tailstock 10 is also arranged on the grinding table 28 so that the machine component 2 is usually clamped between the workhead 9 and the tailstock 10 on a common axis of rotation, the longitudinal axis 1 of the machine component 2 . Measuring devices 23.1, 23.2 and 23.3 are provided in the grinding machine for process monitoring, which are used to measure the outside and/or inside diameter. The measuring signals obtained from the measuring devices serve to monitor and control the grinding machine, in that the measuring signals are fed directly to the control of the grinding machine in the usual way. A dressing device 29 is also provided in the usual way, which is used for dressing of the grinding wheels available on the grinding machine. Also shown is a bezel 22 which, when in active use, partially encompasses the machine component on the circumference and is only provided if the machine component is relatively long, in order to compensate for the grinding forces introduced by grinding grinding wheels when grinding the outer contour. A steady rest at the end area of the machine component for the purpose of internal grinding, as is required in the prior art, is not required. It is only optional and only serves to avoid the deflection of a relatively long machine component that may be caused by grinding forces. The steady rest is unnecessary for shorter components that have sufficient flexural rigidity.

The grinding machine has a grinding headstock 18 which has a grinding spindle 25 with a grinding wheel 8 for internal grinding, a grinding spindle 26.1 with a first external grinding wheel 16.1 and a grinding spindle 26.2 with a second external grinding wheel 16.2. i.e. The three grinding spindles 25, 26.1 and 26.2 are all arranged on the common grinding headstock 18. The grinding headstock 18 can be pivoted about a pivot axis 24 and is arranged on a carriage 19.1. The carriage 19.1 in turn is perpendicular to the common axis of rotation, i. H. the longitudinal axis 1, slidably arranged. The slide 19.1 can therefore be displaced in the direction of the usual X-axis. The pivoting movement of the grinding headstock 18 is indicated by the curved double arrow B. The displacement movement of the carriage 19.1 is indicated by the straight double arrow X. Z indicates the displacement movement in the direction of the longitudinal axis 1 of the machine component 2, while C indicates the rotation of the machine component about the common axis of rotation, i. H. Long axis, designated. By pivoting the grinding headstock 18, the grinding wheels required for the machining, d. H. the inner grinding wheel 8, the first outer grinding wheel 16.1 and the second outer grinding wheel 16.2, are brought into engagement with the machine component 2 in order to carry out their respective grinding task.

In the described embodiment according to 1 the outer contour and the inner contour of the machine component 2 are ground one after the other, since the respective grinding tasks can only be carried out one after the other due to the joint arrangement of all grinding wheels with their grinding spindles on a grinding headstock 18 . In any case, however, the machine component remains clamped in one and the same clamping with one and the same centering in the grinding machine according to the invention, both for grinding the outer contour and grinding the inner contour. The first outer grinding wheel 16.1 is used to grind the outer contour of the machine component 2. The second outer grinding wheel 16.2 can grind both rotationally symmetrical peripheral surfaces and end faces on the machine component 2. This ensures that the machine component 2 may be present End faces can also be ground in the same clamping. The grinding spindle 25 carries the inner grinding wheel 8 , which has a small diameter and is used to grind the rotationally symmetrical inner recess 6 of the machine component 2 , in that the inner grinding wheel 8 passes through the tailstock hollow quill 15 . Because of the small diameter of the inner grinding wheel 8, it is also referred to as a mounted point. To carry out the method according to the invention, it is sufficient if only the internal grinding spindle 25 with the internal grinding wheel 8 and the grinding spindle 26.2 with the external grinding wheel 16.2 are provided. The grinding spindle 26.1 with its external grinding wheel 16.1, which is also arranged on the grinding headstock 18, can be used for further machining processes on the machine component, for example to grind further peripheral and end faces or recesses.

When grinding the inner recess 6 by means of the inner grinding wheel 8 through the tailstock hollow sleeve 15, there is another advantage of the method according to the invention, namely that the cooling lubricant is guided directly through the tailstock hollow sleeve 15 to the inner surface of the inner recess 6, with which the inner grinding wheel 8 when grinding the inner recess 6 is engaged. This makes it possible for the cooling lubricant to be fed directly and directly to the grinding area in an optimal manner.

2 shows a basic representation of a grinding machine according to the invention in a plan view, which essentially corresponds to the grinding machine 1 is equivalent to. In this respect, the same reference numerals relate to the same components or components. In contrast to 1 However, according to the grinding machine 2 an additional internal grinding headstock 30 in the area of the tailstock 10 . This internal grinding headstock 30 is also arranged on the machine bed 27 and, in the manner of a further, second carriage 19.2, carries a further internal grinding spindle 31, which carries a further internal grinding wheel 32. The other internal grinding spindle 31 can be moved on the carriage 19.2 in the Z2 direction, ie in the direction of the longitudinal axis 1 of the machine component 2, and can thus be inserted through the tailstock hollow sleeve 15 into the inner recess 6 for machining. In addition, the carriage 19.2 can be moved in the X2 direction, so that the feed for grinding in the inner recess can be adjusted accordingly.

3 shows a detailed view of the basic structure of the grinding machine according to the invention 1 . The machine component 2 is clamped with respect to its longitudinal axis 1 between the centers on the work headstock 9 in the chuck 11 with the clamping jaws 12 and the center point 13 and on the tailstock 10 by means of the tailstock hollow sleeve 15 and the hollow center 20 running in the middle. This tension between the tips remains throughout Edit received. In its left half, the machine component 2 has a peripheral collar which has planar sides facing the workpiece headstock 9 and the tailstock hollow quill 15 . In addition, the machine component 2 has a shoulder in the area where it is clamped in the workhead headstock 9, which shoulder also forms a flat side. On the grinding headstock 18, whose pivotability is indicated by the curved double arrow B, the grinding spindle 26 is pivoted with the external grinding wheel 16 for external grinding in the direction of the workpiece. The entire cylindrical outer contour 17 of the machine component 2 is ground by means of the outer grinding wheel 16 . The outer grinding wheel 16 is designed in such a way that it can also grind the flat sides on the machine component 2 with its end faces. On the one hand, the outer grinding side 16 is infed via the X-axis onto the outer contour 17 of the machine component 2 so that the outer grinding can be carried out using this outer grinding wheel 16 . By being able to move the grinding spindle 26 together with its outer grinding wheel 16 in the Z-direction, the flat sides on the circumferential collar as well as the flat side on the shoulder in the area of the work headstock 9 can be ground. This makes it possible to grind the entire outer contour of the machine component 2 .

The tailstock 10 is not equipped with the usual quill, but has a very short quill, which is hollow drilled on the inside. A hollow center 20 is provided in the bore of the tailstock hollow quill 15, which represents the center of the tailstock and which engages in the phases provided in the front end area of the machine component 2 in such a way that the machine component 2 is centered with respect to its longitudinal axis 1 at the end facing the tailstock 10 with respect to the Longitudinal axis 1 is spanned. The hollow bore of the tailstock hollow quill 15 allows a grinding wheel (not shown) for internal grinding to reach through the hollow bore into the area of the inner recess 6 of the machine component 2 in order to machine the inner recess there.

In 4 Fig. 12 is a detail and plan view of a grinding machine as shown in Fig 1 shown, in which the inner recess 6 on the machine component 2 is ground. The machine component 2 is in turn held centrally at its left end in the work headstock 9 by means of the chuck 11 and the clamping jaw 12 and the center point 13 . Likewise, the machine component 2 is also clamped centrally on the opposite end 5 in the tailstock 10 with its tailstock hollow sleeve 15 via the hollow center 20 running therein, in such a way that the longitudinal axis 1 of the machine component 2 forms its axis of rotation. The outer contour 17 of the machine component was ground in such a way as in connection with 3 has been described. For internal grinding of the inner recess 6, the internal grinding wheel 8 with its internal grinding spindle 25, which mounted on the grinding headstock 18 and pivotable about its pivot axis 24, pivoted through the hollow bore of the tailstock hollow sleeve 15 into the recess 6 of the machine component 2 and brought into grinding engagement there. For this purpose, in addition to the pivotability of the internal grinding spindle 25 about the pivot axis 24, the grinding headstock 18 can be brought into grinding engagement along the X-axis in the internal recess. In addition, for the purpose of guiding the internal grinding wheel 8 through the grinding stock hollow quill 15, this can be moved in the Z direction in such a way that the internal grinding wheel 8 can be guided through the hollow bore of the tailstock hollow quill 15 into the internal recess 6 of the machine component 2.

The tailstock 10 is stored very short, i. H. Short in axial alignment and - as described - drilled hollow on the inside. During internal grinding, the machine component 2 remains clamped between the centers.

figure 5 shows the machine component 2 in an enlarged detailed view, which is centrally clamped in the chuck 11 in the clamping jaws 12 by means of the centering point 13 on the longitudinal end face 14 of the machine component 2 . At the opposite end 5 of the machine component 2, the revolving hollow center 20 of the tailstock hollow quill 15 serves to clamp the machine component 2 centrally overall.

In contrast to the statements according to 3 and 4 An embodiment is shown here in which the outer contour 17 is ground by means of the outer grinding wheel 16 on the grinding headstock 18 (not shown), whereas the inner grinding wheel 8 mounted on the inner grinding spindle 25 passes through the hollow bore of the tailstock sleeve 15 into the inner recess 6 for grinding its inner Peripheral surface 7 can be passed. in the in figure 5 In the position shown, the internal grinding wheel 8 is in a position before it is passed through the hollow bore of the tailstock sleeve 15. The internal grinding spindle 25 with the internal grinding wheel 8 in the form of a grinding pin is on a separate internal grinding headstock (not shown) in the Z direction, i.e. in Direction of the longitudinal axis 1, as well as in the X-direction, ie in the direction of a grinding engagement on the peripheral surface 7 of the inner recess 6 deliverable.

The bearing of the tailstock hollow quill 15 is provided with high-precision spindle bearings, with the revolving hollow point 20 running in the center with the machine component 2 due to the friction caused by the clamping forces. The live hollow point 20 engages an inner surface at the opposite end 5 of the machine component 2 in a sealing or form-fitting manner. In principle, it would also be possible that with centering clamping using a stationary center, i.e. a center that does not rotate, the machining on machine component 2 is performed. It would also be possible, but this is not shown here, for the tailstock hollow sleeve 15 to be designed as a hydrodynamic or hydrostatic bearing.

Cooling lubricant is supplied on the side of the work headstock 9 through the center point 13 of the chuck 11 . This makes it possible for cooling lubricant to reliably reach the inner recess 6 from the side of the work headstock so that it can be ground by means of the inner grinding wheel 8 . However, this is of course only possible if the machine component 2 has a continuous bore. So that sufficient cooling lubricant supplied can reach the direct grinding action during internal grinding, the internal grinding wheel 8 has a conical attachment on its front face, which is used to feed the cooling lubricant directly to the grinding action. Reliable lubrication is particularly important for internal grinding because the internal grinding wheel 8 nestles into the peripheral surface 7 to be ground, so to speak, and the area of contact of the grinding wheel on the peripheral surface 7 of the internal recess 6 is therefore larger than when externally grinding a cylindrical or even non-cylindrical one surface would be the case.

6 shows a representation according to figure 5 , in which, however, the internal grinding wheel 8 has been brought into grinding engagement with the circumferential surface 7 of the inner recess 6 of the machine component 2 through the hollow bore of the tailstock hollow sleeve 15 . The other components or components denoted by corresponding reference numerals correspond to those according to FIG figure 5 and are therefore not explained in more detail here.

7 shows a further exemplary embodiment of a grinding machine according to the invention, in which two separate grinding headstocks 18.1, 18.2 are shown on the machine bed 27. The two grinding headstocks 18.1, 18.2 each carry an external grinding wheel 16.1 or 16.2 and an internal grinding wheel 8.1 with the associated internal grinding spindle 25.1 or 8.2 with the associated internal grinding spindle 15.2. The grinding headstock 18.1 can be pivoted about a pivot axis B1, which is identified by the double arrow. In an analogous manner, the grinding headstock 18.2 can be pivoted about a pivot axis B2, which is also identified by the double arrow. The grinding headstocks 18.1 and 18.2 can be advanced in the X1 or X2 axis direction and moved in the Z1 or Z2 direction in the direction of the longitudinal axis 1 of the machine component 2 in the usual way. This makes it possible for the corresponding outer grinding wheel 16.1 or 16.2 to be brought into engagement for grinding the outer contour of the machine component 2, whereas the machine component 2, which has a central bore, is centered both at its left end and at its opposite end 5 by means of respective hollow sleeves is stretched so that at each end there is an inner recess Having machine component 2 can be ground on both sides inside with the internal grinding wheels 8.1 and 8.2. With such a configuration it is thus possible that the machine component 2, which is arranged at one end in a work headstock 9.1 arranged on the grinding table 28 in the manner described above, but which is designed with a hollow chuck, and at the opposite end 5 in a tailstock -Hollow quill 15 is held by means of respective hollow tips 20.1 and 20.2 (see 8 ) is held in such a way that the left-hand and the right-hand inner recess can be ground at least temporarily at the same time. With this configuration, however, it is also possible for the corresponding inner recess to be ground, at least at times parallel to the grinding of the outer contour, using either the first outer grinding wheel 16.1 or the second outer grinding wheel 16.2 with one of the inner grinding wheels arranged on the other grinding headstock. It is also possible that the two outer grinding wheels 16.1 and 16.2 can be used to grind the outer contour at least temporarily, using one of the two grinding wheels, while the planar surfaces are ground with the other of the two grinding wheels. With such an arrangement, the flexibility of the grinding machine according to the invention is further increased, even if the outlay on equipment is higher. With such an arrangement, a reduced cycle time can be achieved despite the more complex contours of the machine components to be ground. The workhead headstock 9.1 is driven by a drive motor 33, which is arranged with a housing axis-parallel to the longitudinal axis 1 of the machine component 2. The tailstock 10 can be moved in the Z direction, but is not driven.

In 8 is the basic arrangement according to 7 shown in an enlarged view, but only the two internal grinding wheels 8.2 with the associated internal grinding spindle 25.2 and internal grinding wheel 8.1 with the associated internal grinding spindle 25.1 are available for insertion through the respective hollow bores of the workpiece headstock 9.1 and the tailstock 10. The bearing and drive of the work headstock 9.1 are shown at the left-hand end of the machine component 2, which is clamped in the center. In order to drive the center point 20.1 or the chuck, the drive or drive motor 33 realized by means of belts, in particular toothed belts, is provided in addition to the structurally short bearing of this hollow workpiece headstock 9.1. The possible at least partially time-parallel processing of the outer and inner contours of the machine component 2 to be ground takes place in the order and manner described above in connection with the other figures.

And finally is in 9 a simplified embodiment shown for grinding a machine component 2, which - unlike in the Figures 1 to 8 - is not a shaft part, but a gear component. The corresponding grinding headstocks are for simplicity not shown for the sake of it. The centered clamping of this gear component takes place in that the chuck 11 clamps the gear with its clamping jaws 12 on its outer toothing. Planar stops are also provided on the chuck 11 to achieve an exact alignment, against which the gear wheel is clamped. As a result, a clear orientation of the reference axis, namely the longitudinal axis 1 of the gear wheel 2, which is fixed for the entire machining operation, is realized. Profiled outer sections on the hub area of the gear wheel are ground by means of a profiled outer grinding wheel 16.1, which is mounted in a rotationally driven manner on a corresponding grinding spindle 26.1. Furthermore, an internal grinding wheel 8 is provided, which is mounted in a rotationally driven manner on its associated internal grinding spindle 21, which can be moved into the hub bore on a separate grinding headstock via the Z3 axis, so that the hub bore is at least parallel to the outer contour via an infeed along the X3 axis can be ground. On the side of the chuck 11, an additional grinding headstock (not shown) is provided, which carries a grinding wheel 16.2 with the associated spindle 26.2. The outer grinding wheel 16.2 is a profiled grinding wheel and is used to grind the flat sides on the collar or on the hub of the gear wheel 2. According to the invention, this gear wheel can also be ground at least temporarily on both its outer and inner contour at the same time.

Reference number list:

1

longitudinal axis

2

machine part

3

axial end

4

bearing journal

5

opposite end

6

interior recess

6.1

further interior recess

7

peripheral surface

8th

internal grinding wheel

8.1

first internal grinding wheel

8.2

second internal grinding wheel

9

workhead

9.1

Workhead with hollow quill

10

tailstock

11

chuck

12

clamping jaws

13

center point

14

face

15

Tailstock hollow quill

16

external grinding wheel

16.1

first external grinding wheel

16.2

second external grinding wheel

17

outer contour

18

grinding headstock

18.1

first wheelhead

18.2

second grinding headstock

19.1

first sled

19.2

second sled

20

revolving hollow point

20.1

Hollow-point workstock headstock

20.2

Hollow point tailstock

22

bezel

23.1

first measuring device

23.2

second measuring device

23.3

third measuring device

24

pivot axis

25

Grinding spindle internal grinding wheel

25.1

first internal grinding spindle

25.2

second internal grinding spindle

26

Grinding spindle external grinding wheel

26.1

Grinding spindle first external grinding wheel

26.2

Grinding spindle second external grinding wheel

27

machine bed

28

grinding table

29

dressing device

30

additional internal grinding headstock

31

additional internal grinding spindle

32

another internal grinding wheel

33

drive / drive motor

Claims (17)

1. Method for the grinding machining, carried out in a single clamping, of a machine component (2) which is driven in rotation about its longitudinal axis (1), which is clamped at its two axial ends (3, 5) and has an internal recess (6) on at least one of its ends (5), which is ground by means of an internal grinding wheel (8), the machine component (2) being held in a single clamping between a workpiece headstock (9) and a tailstock (10) rotarily driven and ground on its outer contour (17) by means of at least one grinding wheel (16), wherein

   a) the machine component (2) is held centred on the tailstock (10) by means of a revolving or rotary driven tailstock hollow sleeve (15) with a hollow tip at the end region of the internal recess (6);

   b) the internal grinding wheel (8) engages through the tailstock hollow sleeve (15) during grinding of the internal recess (6), and

   c) the clamping on the workpiece headstock (9) is carried out with a centrically clamping chuck or with a chuck (11) with compensating clamping jaws (12) and a centring point (13, 20.1) engaging in the end face (14) of the machine component (2).
2. Method according to claim 1, characterised in that the grinding of the inner recess (6) and the grinding of the outer contour (17) of the machine component (2) are carried out at least at times in parallel.
3. Method according to claim 1 or 2, in which the grinding operation is carried out without any change in the reference axes and without steady rest support.
4. Method according to claim 1, 2 or 3, in which the centre point (20.1) is hollow and is penetrated by a further internal grinding wheel (8.1) for grinding a further internal recess (6.1).
5. Method according to one of claims 1, 3 or 4, in which the internal grinding wheel (8) and the grinding wheel (16) are brought into and out of engagement with the machine component (2) by pivoting and/or moving a common grinding headstock (18), in particular steplessly, which are moved by a pivotable arrangement on a carriage (19.1) for grinding the internal recess (6, 6.1) and in a direction parallel to the longitudinal axis (1) of the machine component (2) for grinding the external contour (17).
6. Method according to one of claims 1 or 3 to 5, in which the grinding wheel (16) is arranged on a grinding headstock (18, 18.1) and is brought into grinding engagement with the machine component (2) by pivoting thereof.
7. Method according to claim 6, in which the internal grinding wheel (8) is arranged on a separate grinding headstock (18.2) in the region of the tailstock (10) and is moved in the direction of the longitudinal axis (1) of the machine component (2) in order to engage through the tailstock hollow sleeve (15).
8. Method according to one of claims 1 to 7, in which, during grinding of the outer contour (17) of the machine component (2), the axis of rotation of the grinding wheel (16) and the common longitudinal axis running through the workpiece headstock, machine component and tailstock run at an oblique angle to one another in space in such a way that there is essentially only point contact between the grinding wheel (16) and the outer contour (17) of the machine component, the longitudinal feed being in the direction of the workpiece headstock (9, 9.1).
9. A method according to any one of claims 1 to 7, wherein, when grinding the outer contour (17) of the machine part (2), the axis of rotation of the grinding wheel (16) and the common axis of rotation extending through the workpiece headstock, machine component and tailstock extend at an angle to each other in the plane such that there is substantially linear contact between the grinding wheel (16) and the outer contour (17) of the machine part (2) in the sense of angular plunge grinding.
10. Method according to one of the claims 1 to 9, in which both circumferential areas and end faces of the machine component (2) are ground with the grinding wheel (16, 16.1, 16.2).
11. Method according to any one of claims 1 to 10, wherein the tailstock hollow sleeve (15) is designed to rotate with the tailstock.
12. Method according to one of claims 1 to 11, in which the grinding of the machine component (2) is CNC-controlled.
13. Grinding machine of the type of a universal cylindrical grinding machine and/or non-cylindrical grinding machine for carrying out the method according to any one of claims 1 to 12, in which the following features are provided:

    a) a workpiece headstock (9, 9.1) and a tailstock (10) are arranged on a grinding table (28), between which a machine component (2) to be ground can be clamped, the common longitudinal axis running through the workpiece headstock (9, 9.1), machine component (2) and tailstock (10) extending in the longitudinal direction of the grinding table (28);

    b) the workpiece headstock (9, 9.1) has a centrically clamping chuck (11) or a chuck (11) with compensating releasable clamping jaws (12) and a centring point (13, 20.1) which holds the machine component (2) on the workpiece headstock (9, 9.1) in a rotationally driving manner;

    c) the tailstock (10) has a tailstock hollow sleeve (15) which is designed as a revolving or rotary driven tailstock and has a hollow tip (20, 20.2) which is adapted for centring engagement at least in a rotationally symmetrical inner recess (6) at the end (5) of the machine component (2) opposite the workpiece headstock (9, 9.1);

    d) the tailstock hollow sleeve (15) with the hollow tip (20, 20.2) has an internal bore which can be penetrated by an internal grinding wheel (8, 8.1) carried by a grinding headstock (18, 18.1, 25) for grinding the internal recess (6);

    e) the workpiece headstock (9, 9.1) and the tailstock (10) are movable relative to each other in such a way that the machine component (2) is held and rotarily driven between the centre point (13, 20.1) on the workpiece headstock (9, 9.1) and the hollow point (20, 20.1) on the tailstock (10) under axial pressure and with the reference axis unchanged in the clamping, and

    f) a grinding wheel (16.1) for grinding the outer contour of the machine component (2).
14. Grinding machine according to claim 13, in which the grinding headstock (18, 18.1) carrying the internal grinding wheel (8, 8.1) is pivotable about a vertical pivot axis (24) and is arranged on a carriage (19.1) which is displaceable in a controlled manner perpendicularly to the longitudinal direction of the grinding table (28) and additionally accommodates a rotary driven grinding wheel (16.1) having a horizontally extending axis of rotation for grinding the outer contour (17) of the machine component (2).
15. Grinding machine according to claim 13 or 14, in which the grinding headstock (18, 18.1, 18.2) carrying the internal grinding wheel (8, 8.2) is a separate grinding headstock (30) in the region of the tailstock (1) and/or in the region of the chuck (11) having a hollow tip as a centre point (20.1), and the internal grinding wheel (8, 8.1) can be advanced into the internal recess (6) and against its circumferential surface (7).
16. Grinding machine according to any one of claims 13 to 15, in which the grinding wheel (16, 16.1, 16.2) is provided with an abrasive coating on both its periphery and its end face.
17. Grinding machine according to one of claims 13 to 16, in which the chuck (11) is hollow and can be penetrated by means of a further internal grinding wheel (8.1) for grinding a further internal recess (6.1) at the workpiece headstock end (3) of the machine component (2).

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