WO2023052421A1

WO2023052421A1 - Method and device for grinding an elongate workpiece

Info

Publication number: WO2023052421A1
Application number: PCT/EP2022/076979
Authority: WO
Inventors: Michael Bergbaur; Manfred Sägmüller
Original assignee: Vollmer Werke Maschinenfabrik Gmbh
Priority date: 2021-09-28
Filing date: 2022-09-28
Publication date: 2023-04-06
Also published as: DE102021125106A1; WO2023052421A4; CN118019615A

Abstract

The present invention relates to a method for grinding an elongate workpiece (14), comprising the following steps: - clamping the workpiece (14), wherein the workpiece (14) is supported at a first workpiece end (82) in a first workpiece holder (12) by means of a first centring device (44) and at a second workpiece end (84) in a second workpiece holder (78) by means of a second centring device (80); - performing a first grinding step on at least a first portion of the outer surface of the workpiece (14) by means of a tool assembly (18); - re-clamping the workpiece (14), wherein the workpiece (14) is released by the first and the second centring device (44, 80) and one of the workpiece ends (82, 84) is received in the first workpiece holder (12); and - performing a second grinding step on a second portion of the outer surface of the workpiece (14) by means of the tool assembly (18), wherein a bearing device (69) supports the workpiece (14) over at least part of the outer surface of the workpiece (14).

Description

Method and apparatus for grinding an elongate workpiece

The present invention relates to a method and apparatus for grinding an elongate workpiece.

Workpieces can be ground in different ways. In the case of rotationally symmetrical, elongate workpieces, it is generally first necessary to bring a blank of the workpiece into a rotationally symmetrical shape in order to then carry out further grinding operations on the workpiece. In order to grind the blank in a rotationally symmetrical manner, it is advantageous to store the workpiece over its end faces so that the entire lateral surface of the workpiece can be freely machined.

In the case of rotationally symmetrical workpieces, the ratio of workpiece length to workpiece diameter of the workpiece is particularly large or becomes large due to the material removal caused by grinding, and which are to be ground up to a first end of the workpiece, it is known that the workpiece is only ground at its second end to be stored in a workpiece holder and also close to the tool over the lateral surface of the workpiece by means of a support. In this way, the pressure required for grinding can be applied to the workpiece with a grinding tool and, at the same time, sufficient support for the workpiece to absorb the pressure can be ensured by storing it close to the tool. Deviations from a desired workpiece contour can thus be avoided.

DE 694 21 859 T2 discloses a grinding machine for machining a rotationally symmetrical workpiece which has a large ratio of workpiece length to workpiece diameter. A spindle carrying one end of the workpiece is mounted on a machine bed with a headstock so that it can be moved relative to two opposite grinding wheels along a longitudinal axis of the workpiece. Furthermore, a support for storing the workpiece over its lateral surface is arranged in a stationary manner on the machine bed. In order to grind the rotationally symmetrical workpiece to a predetermined diameter, the workpiece and grinding wheels are driven in rotation and the workpiece is moved over the headstock relative to the machine bed and in the direction of the grinding wheels along the workpiece axis.

These different grinding processes explained above are usually carried out on different grinding devices which are aimed at the individual grinding processes. However, a large number of different grinding devices is associated with high investment costs. This is particularly disadvantageous in the case of smaller quantities. In addition, a large number of clamping devices to be passed through by a workpiece regularly leads to a long throughput time for the workpiece.

There is therefore a need to provide a time-optimal and at the same time simple grinding processing of elongate workpieces.

This object is achieved by the method according to claim 1. Furthermore, this object is achieved by the device according to claim 12. The dependent claims relate to advantageous developments of the invention.

The method according to the invention for grinding an elongate workpiece comprises the following steps:

- Clamping of the workpiece, wherein the workpiece is stored at a first workpiece end by means of a first centering device in a first workpiece holder and at a second workpiece end by means of a second centering device in a second workpiece holder;

Carrying out a first grinding step on at least a first section of a lateral surface of the workpiece by means of a tool arrangement; Re-clamping of the workpiece, the workpiece being decoupled from the first and the second centering device and one of the workpiece ends being received in the first workpiece holder; and

Carrying out a second grinding machining step on a second section of the lateral surface of the workpiece by means of the tool arrangement, with a storage device supporting the workpiece over at least a part of the lateral surface of the workpiece.

The clamping of the workpiece at the workpiece ends makes it possible for the workpiece to be machined flexibly and, in particular, over the entire lateral surface of the workpiece. In addition, it is made possible that the workpiece can be stored by means of the workpiece holders despite unevenness in the lateral surface. Thus, the workpiece, which has a workpiece longitudinal axis, can be easily clamped and stored, even if it initially has a non-rotationally symmetrical shape with respect to the workpiece longitudinal axis.

By means of the centering can be achieved that the clamped workpiece has a defined position with respect to the workpiece holders and thus also with respect to the Tool arrangement occupies. In other words, the centering devices can be used to ensure that the workpiece has a defined longitudinal axis, to which the rotational symmetry of the workpiece is related. The workpiece can be rotated about this longitudinal axis of the workpiece.

A desired geometry or outer contour can be produced in the first section of the workpiece by means of the first grinding machining step. The entire lateral surface of the workpiece is available for the first grinding step, since the workpiece is supported by the ends of the workpiece. The outer surface extends between the two ends of the workpiece. The support fixture does not engage or support the workpiece during the first grinding operation.

The re-clamping ensures that the workpiece no longer comes into contact with the centering devices. Furthermore, it is achieved that the workpiece is no longer stored by means of the second workpiece holder. Depending on the orientation of the workpiece with which the workpiece is received in the first workpiece holder, for example, a region of the workpiece jacket surface assigned to the second workpiece end can be flexibly machined, provided the storage device does not store the workpiece directly there. This is particularly advantageous for rotationally symmetrical workpieces that require machining up to one end of the workpiece. A defined positioning of the workpiece can be achieved by receiving the end of a workpiece in the first workpiece holder. In this case, it can be provided that the first workpiece holder encompasses and supports the workpiece on a region of the workpiece lateral surface assigned to the first or second workpiece end. As a result, a secure gripping or storage in the first workpiece holder can be achieved. After the workpiece lateral surface has been machined at least in the first section in the first grinding machining step, the workpiece can therefore be gripped there in order to store the workpiece in a defined manner.

Due to the storage device that supports the workpiece during the second grinding processing step, the workpiece can be processed even if it is comparatively long and thin. Forces that arise as a result of the grinding machining can be absorbed by the bearing device. Deflection of the workpiece can be effectively avoided. Workpieces that have a particularly large ratio of workpiece length to workpiece diameter can also be machined with high precision.

Overall, the method according to the invention provides efficient grinding of elongate workpieces. According to a development of the invention, it can be provided that during clamping the workpiece is coupled to the first centering device via an axial end face of the workpiece and/or a centering in an axial end face of the workpiece and/or a chamfer in particular adjoining the axial end face of the workpiece and/or is coupled to the second centering device via a further axial face and/or a further centering in a further axial face of the workpiece and/or a further chamfer in particular adjoining the further axial face of the workpiece. It can thereby be achieved that the entire lateral surface of the workpiece can be machined essentially or completely freely. At the same time, the workpiece is stored in a defined manner. When clamping, it is advantageous if the two end faces are arranged parallel to one another. If this is not the case, provision can be made for the end faces of the workpiece to be machined in a preceding machining step, so that they are parallel to one another. "Axial" in relation to the workpiece generally means in the direction of the longitudinal axis of the workpiece.

According to one aspect of the invention, provision can be made for the first workpiece holder to approach the tool arrangement at a first speed during the first grinding machining step. In this way, easy machining along the first section can be achieved. Alternatively, provision can be made for the first workpiece holder of the tool arrangement to move away at a first speed during the first grinding machining step.

According to one embodiment of the invention, provision can be made for the bearing device to approach the tool arrangement at a second speed during the first grinding machining step.

According to one aspect of the invention, it can be provided that the second speed is lower than the first speed. The storage device is thus increasingly approaching the first workpiece holder.

According to a development of the invention, it can be provided that the first and/or second grinding machining step includes peel grinding.

According to one aspect of the invention, it can be provided that the workpiece is ground into a rotationally symmetrical shape at least in the first grinding machining step in the first section. The rotational symmetry is related to the longitudinal axis of the workpiece. This is advantageous for further grinding processing and enables the workpiece to be picked up in a defined manner in the first workpiece holder during re-clamping. According to one embodiment of the invention, it can be provided that the first section encompasses the entire lateral surface of the workpiece. Thus, complete grinding of the lateral surface of the workpiece can be achieved in the first grinding step. This facilitates handling, subsequent grinding processing steps and subsequent storage.

According to one aspect of the invention, it can be provided that during re-clamping, the workpiece is supported over the lateral surface of the workpiece by means of the bearing device before and/or during decoupling, in particular is clamped by means of the bearing device. In this way, a defined position of the workpiece can be reached during re-clamping. Clamping prevents the workpiece from tilting or slipping unintentionally. The workpiece can be held securely.

According to a development of the invention, it can be provided that a gripper is provided for gripping the first centering device, which grips the first centering device during reclamping and removes it from an area between the first workpiece holder and the first workpiece end. Thus, it may be sufficient that only a translational movement relative to one another along a defined axis is required between the first workpiece holder and the workpiece. Overall, a simple and time-saving re-clamping can thus be achieved.

According to one embodiment of the invention, it can be provided that the second section is arranged within the first section or corresponds to the first section. It can thus be achieved that the region of the lateral surface of the workpiece that was previously machined in the first grinding machining step is machined by means of the second grinding machining step.

According to a development of the invention, it can be provided that, in particular during the second grinding machining step, the tool arrangement engages with the workpiece offset in the direction of the longitudinal axis of the workpiece compared to an engagement region of the bearing device, in particular on a side of the bearing device facing away from the first workpiece holder. Due to the offset, a large engagement area on the workpiece can be achieved for the tool holder. At the same time, the grinding processing does not take place where at the same time the storage device stores the workpiece. Safe storage by means of the storage device is thus guaranteed. Provision can be made for the offset to be small in relation to the workpiece length and to be 1/20, 1/30 or 1/40, for example. This allows forces due to grinding with a good or short force flow in the workpiece from the bearing Device can be included. Deformation or deflection of the workpiece due to the grinding processing can be avoided or at least reduced. The aim is for the workpiece to be machined as close as possible to the storage device using the tool arrangement.

Provision can be made according to the invention for the workpiece to be moved in the direction of the longitudinal axis of the workpiece relative to the bearing device during the first and/or second grinding machining step. The workpiece can be mounted on the bearing device so that it can be displaced or slid in the direction of the longitudinal axis of the workpiece, at least during the second grinding machining step.

According to a further development of the invention, it can be provided that the bearing device and the tool arrangement are at a constant distance from one another during the second grinding machining step.

Alternatively, according to one aspect of the invention, provision can be made for the bearing device to be arranged at a fixed location on the workpiece with respect to the longitudinal axis of the workpiece, at least during the second grinding machining step. The storage device then moves in the direction of the longitudinal axis of the workpiece simultaneously with the first workpiece holder.

According to a development of the alternative aspect, it can be provided that the distance between the bearing device and the tool arrangement is varied, preferably reduced, during the second grinding machining step. Overall, the alternative embodiment enables so-called on-the-fly machining, in which a workpiece length to be machined is freely accessible during the second grinding machining step without the influence of the storage device. This is particularly advantageous when generating non-rotationally symmetrical profiles or contours on the workpiece and/or when repeating the second grinding machining step several times.

According to one aspect of the invention, it can be provided that during the second grinding step the tool arrangement is at least partially oriented differently than in the first grinding step. For example, despite the same machining tool or the same machining tools that are in engagement with the workpiece, a different type of grinding operation can be achieved compared to the first grinding operation. According to one development of the invention, it can be provided that in the second grinding step, a region of a first workpiece surface is ground to a first workpiece diameter and a region of a second workpiece surface is ground to a second workpiece diameter, with the first diameter being smaller than the second diameter. It can be provided that the second lateral surface of the workpiece is arranged closer to the first workpiece holder than the second lateral surface of the workpiece. Provision can also be made for a region of a third, fourth, etc. lateral surface of the workpiece to be ground to an associated diameter. All diameters or some of the diameters may differ. Provision can be made for the diameters to decrease or increase with the distance from the first workpiece holder.

According to a further aspect of the invention, it can be provided that in the second grinding step in a region of a first lateral surface of the workpiece a variable diameter, in particular one that is constant along the longitudinal axis of the workpiece or runs according to a function, is formed.

According to a development of the invention, it can be provided that at least one of the two workpiece holders, in particular the first workpiece holder, comprises a rotatably drivable workpiece spindle and the workpiece is rotationally driven at least during the first and second grinding machining step by means of the rotationally driven workpiece spindle. The rotary drive takes place around the longitudinal axis of the workpiece.

According to one aspect of the invention, it can be provided that after the first grinding step, at least one workpiece diameter is measured in the first section and/or after the second grinding step, at least one workpiece diameter is measured in the second section. It can thus be checked whether the workpiece has reached a specified dimension. If this is not the case, provision can be made, for example, for the first or second grinding machining step to be repeated.

According to a development of the invention, it can be provided that the measurement is repeated at least once and, if necessary, the first grinding step is repeated until the workpiece has reached the specified dimension.

According to one aspect of the invention, it can also be provided that a workpiece length, in particular a position of the first or second workpiece end, is measured after the reclamping. Whether the position of the first or second workpiece end is measured depends on the orientation in which the workpiece is held in the first workpiece holder. In other words, it is advantageous to measure the position of the workpiece end facing away from the first workpiece holder. This may be necessary in order to carry out the second grinding step with high accuracy and to start the second grinding step directly at the first or second workpiece end.

The measurement described above can be carried out using respective measuring devices or using a common measuring device, in particular a probe.

The method described above and/or further developments of the method described above can advantageously be carried out on a single device, in particular a grinding machining device.

According to a further development of the invention, it can be provided that after the second grinding step the elongate workpiece has a non-rotationally symmetrical shape at least in the second section, with a non-rotationally symmetrical shape of the elongate workpiece preferably being produced by means of the second grinding step. It can be provided that the elongate workpiece has a polygonal, oval or otherwise complex shape after the second grinding machining step. This can be accomplished in particular by means of a coordinated movement of the workpiece in the direction of the longitudinal axis of the workpiece relative to the tool arrangement.

Furthermore, the object according to the invention is achieved by a device for grinding an elongate workpiece, the device comprising:

- a first workpiece holder for storing the workpiece via a first workpiece end of the workpiece and a second workpiece holder for storing the workpiece via a second workpiece end of the workpiece;

- a tool assembly for grinding the workpiece;

- A storage device for at least phased storage of the workpiece over at least part of the lateral surface of the workpiece; wherein the device is set up to carry out a method according to one of the preceding types.

The workpiece holders allow the workpiece to be stored over the workpiece ends of the workpiece, both individually and jointly. Storage over the workpiece ends means that the workpiece is held directly or via an intermediate piece, for example via a centering device, can be connected to the respective workpiece holder.

According to a development of the invention, it can be provided that the storage device comprises a support with a storage trough. The storage trough can serve to accommodate the workpiece, but still allow movement of the workpiece in the direction of the longitudinal axis of the workpiece relative to the storage device. To enhance sliding movement of the workpiece relative to the cradle, the cradle may be formed of or coated with a material having a low coefficient of friction.

According to a further embodiment of the invention, it can be provided that the support is height-adjustable in a height direction perpendicular to a longitudinal axis of the workpiece. In this way, the storage device can store the workpiece despite the different diameters of the workpiece.

According to one aspect of the invention, it is provided that the storage device also comprises a pressure device, in particular a pressure roller, arranged opposite the support, the storage device mounting the workpiece between the support and the pressure device. The pressing device can be used to ensure that the workpiece remains reliably on the support, in particular in the storage trough. The pressure roller also allows the workpiece to rotate relative to the storage device during storage.

According to a development of the invention, it can be provided that the storage device is arranged on a storage carriage which is designed to be movable relative to the tool arrangement and relative to the first workpiece holder in a storage carriage direction. The direction of the bearing carriage can correspond to the longitudinal axis of the workpiece at least during the first or second grinding machining step. The movability allows the workpiece to be easily re-clamped with the aid of the storage device and also easily stored during the second grinding machining step.

According to one embodiment of the invention, it can be provided that the tool arrangement has a first rotationally drivable tool spindle with a first grinding tool and a second rotationally drivable tool spindle with a second grinding tool.

It can be provided according to the invention that the first grinding tool includes a grinding wheel and/or the second grinding tool includes a finishing wheel. In this way, different grinding processes, in particular different coarseness, can be made possible.

In addition, it can be provided according to the invention that the workpiece is arranged between the first and the second grinding tool during the grinding operation.

Furthermore, it can be provided according to the invention that during the first and/or second grinding machining step, a contact area of the first grinding tool with the workpiece is arranged closer to the first workpiece holder than a contact area of the second grinding tool with the workpiece is arranged closer to the first workpiece holder. The contact points are thus offset in relation to the longitudinal axis of the workpiece. Thus, in interaction with a relative movement of the workpiece relative to the tool arrangement, a first grinding operation can be achieved by means of the first grinding tool and a second subsequent grinding operation can be achieved by means of the second grinding tool. Overall, efficient grinding machining of the workpiece can be achieved in this way. This is particularly advantageous when the first grinding tool is designed as a grinding wheel and the second grinding tool is designed as a finishing wheel.

According to a development of the invention, it can be provided that the first grinding tool is arranged on a first tool carriage and the second tool on a second tool carriage for moving the tools in a translation direction perpendicular to the longitudinal axis of the workpiece and perpendicular to the height direction. In this way, the grinding tools can be easily adapted to wear on the grinding tools or material removal from the workpiece.

According to one embodiment of the invention, it can also be provided that the first and/or the second tool carriage is also arranged on a pivoting device for pivoting the grinding tool about a tool carriage axis of rotation, the tool carriage axis of rotation being in the height direction, i.e. perpendicular to a longitudinal axis of the workpiece and perpendicular to the direction of translation. This makes it possible for the first or second grinding tool to engage with the workpiece in a different orientation.

According to a development of the invention, it can be provided that during the second grinding step the first grinding tool is pivoted by an angle about the first pivot axis relative to the first grinding step. According to a development of the invention, the device for grinding can also include a workpiece magazine for receiving workpieces and a workpiece gripper, the workpiece gripper being set up to transport workpieces between the workpiece magazine and a position between the workpiece holders.

According to a development, it can be provided that the workpiece gripper comprises at least two workpiece gripper arms for gripping workpieces. This makes it possible for the workpiece gripper, for example, to hold ready a workpiece to be machined in one workpiece arm and at the same time to be able to pick up a machined workpiece in the other workpiece arm.

According to one aspect of the invention, it can be provided that the device for grinding machining has a guide carriage on which the first workpiece holder is arranged and has a workpiece holder carriage on which the second workpiece holder is arranged, the guide carriage along a workpiece carriage direction and the workpiece holder carriage along a workpiece holder carriage direction are movable. The workpiece carriage direction and the workpiece receiving carriage direction can be parallel or identical to one another. This makes it possible for the workpiece holders to grip workpieces of different lengths. Furthermore, different positions of the workpiece relative to the grinding tools can be implemented.

According to a development, it can be provided that the first workpiece holder is arranged on a carriage, which enables the first workpiece holder to be displaced in a vertical direction. The height direction is preferably oriented perpendicularly to a longitudinal axis of the workpiece or perpendicularly to the direction of the workpiece carriage. Workpieces of different diameters can thus be processed on the device for grinding machining during the second grinding machining step, even if the support is not arranged such that it can be displaced in the height direction. Alternatively or additionally, the second workpiece holder can also be arranged on another slide of this type.

According to a development of the invention, the device for grinding machining also includes a control unit for controlling the device.

It should be noted in general that features, configurations or advantages of the invention that have been explained in connection with the method also apply to the device. Features of the method can thus be realized by the device and in particular be embodied in device features without these device features having to be explicitly mentioned. Conversely, the same applies to features of the device, which also apply to the method.

The invention is explained in more detail below with reference to the attached drawings. They represent:

FIG. 1 shows a perspective view of a device according to the invention according to an exemplary embodiment;

FIG. 2 shows a perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 3 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 4 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 5 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 6 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 7 shows a further detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 8 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 9 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment;

FIG. 10 shows a further perspective detailed view of a device according to the invention according to an exemplary embodiment; FIG. 11a shows a sectional view of a centering device according to a first exemplary embodiment;

FIG. 11b shows a sectional view of a centering device according to a second exemplary embodiment;

FIG. 12a shows a simplified detailed view of a device according to the invention;

FIG. 12b shows a simplified sectional view of a device according to the invention;

FIG. 13a shows a simplified detailed view of a device according to the invention;

FIG. 13b shows a simplified detailed view of the device according to the invention;

Figure 14a is a simplified detailed view of the device according to the invention, the one

performs grinding processing step changed; and

FIG. 14b shows a simplified detailed view of the device according to the invention, which carries out the grinding machining step in a different way.

FIG. 1 shows a view of an inventive device 10 for grinding according to an embodiment. The device 10 comprises a first workpiece holder 12 in which a workpiece 14 is held and which comprises a workpiece spindle 16 which can be driven in rotation and which carries the workpiece 14 . Furthermore, the device 10 comprises a tool arrangement 18 with a first rotationally drivable tool spindle 20 in which a first grinding tool 22 is arranged, and a second rotationally drivable tool spindle 24 in which a second grinding tool 26 is arranged. In addition, the device 10 includes a storage device 69 which is only partially visible here and which is shown partially covered by the tool arrangement 18 . A pressure roller 72 on a pressure arm 74 can be seen as part of the bearing device 69 . The bearing device 69 will be shown in more detail in connection with the other figures. Furthermore, the device 10 includes a magazine 28 with further workpieces 14'. A workpiece gripper 30 is also formed on the device 10 .

The first workpiece holder 12 is arranged on a first guide carriage 32 which is arranged to be movable in a vertical direction Z1 along two rails 36 of a first carriage guide 34 . A second guide carriage 38 is in turn formed on the first carriage guide 34 and can be moved along a second carriage guide 39 is arranged, which is formed on a base body 40 of the device 10. In other words, the first carriage guide 34 can be moved together with the first workpiece holder 12 along a first workpiece carriage direction X1 by means of the second guide carriage 38 and the second carriage guide 39 . The first workpiece carriage direction X1 coincides with the workpiece longitudinal axis W when the workpiece 14 is held in the workpiece holder 12 .

A gripper 42 for gripping the first centering device 44 or the workpiece 14 is also arranged on the first workpiece holder 12 . The gripper 42 is set up to insert the first centering device 44 into the workpiece spindle 16 of the first workpiece holder 12 and to remove it therefrom. For this purpose, the gripper 42 can be pivoted about an axis of rotation C2, which runs in the vertical direction Z1, by means of a gripper actuator 46. Furthermore, the gripper 42 is coupled to the first workpiece holder 12 by means of a gripper carriage arrangement 47 . The gripper carriage arrangement 47 enables the gripper 42 to move on the first workpiece holder 12 along a gripper carriage direction X5, which is arranged parallel to the first workpiece carriage direction X1. In addition, the gripper 42 comprises an actuatable gripper tongs 43 with which the gripper 42 grips the first centering device 44 or the workpiece 14 .

The rotationally drivable workpiece spindle 16 is set up to rotationally drive the workpiece 14 about a workpiece axis of rotation A1. The workpiece axis of rotation A1 runs parallel to the first workpiece carriage direction X1.

The tool arrangement 18 comprises a first tool carriage 48 on which the first tool spindle 20 is formed and which can be moved in a first tool carriage direction Y2 with respect to the base body 40 . The first tool carriage direction Y2 is arranged perpendicularly to the height direction Z1 and perpendicularly to the first workpiece carriage direction X1. The tool arrangement 18 also includes a second tool carriage 50 on which the second tool spindle 24 is arranged and which can be moved in a second tool carriage direction Y1 independently of the first tool carriage 48 relative to the base body 40 . The second tool slide direction Y1 is arranged parallel to the first tool slide direction Y2.

The first tool carriage 48 can also be pivoted by means of a pivoting device 49 relative to the base body 40 about a tool carriage axis of rotation C1, wherein the tool carriage axis of rotation C1 is oriented parallel to the vertical direction Z1 and is arranged perpendicular to the first tool carriage direction Y2. The first tool spindle 20 drives the first grinding tool 22 about a first tool spindle axis of rotation. se A2, which is arranged perpendicular to the tool slide axis of rotation C1. When the first tool carriage 48 is rotated, the orientation of the first tool spindle axis of rotation A2 in space and relative to the base body 40 can be changed. In the present case, the first tool spindle axis of rotation A2 is arranged parallel to the first workpiece slide direction X1. The second tool spindle 24 drives the second grinding tool 26 about a second tool spindle axis of rotation A3, which in the present case is arranged parallel to the first workpiece slide direction X1.

The workpiece gripper 30 is connected to the base body 40 by means of a joint arrangement 52 on a workpiece gripper slide arrangement 54 . The joint arrangement 52 enables the workpiece gripper 30 to be pivoted relative to the workpiece gripper carriage arrangement 54 about a workpiece gripper pivot axis B1. The workpiece gripper pivot axis B1 is arranged parallel to the two tool slide directions Y2, Y1 or perpendicular to the height direction Z1 and the workpiece slide direction X1. The workpiece gripper carriage arrangement 54 enables the workpiece gripper 30 to be moved relative to the base body 40 in a direction Z2 parallel to the vertical direction Z1 and in a further direction Y3. The further direction Y3 is arranged parallel to the tool carriage directions Y2 and Y1 or perpendicular to the height direction Z1 and the workpiece carriage direction X1.

The magazine 28 is arranged on a magazine carriage arrangement 56 which is set up to move the magazine 28 along a magazine carriage direction X4. The magazine carriage direction X4 is arranged parallel to the workpiece carriage direction X1 or perpendicular to the height direction Z1 and the further direction Y3. The magazine carriage arrangement 56 makes it possible to position the magazine 28 in relation to the workpiece gripper 30 in such a way that the latter can remove a workpiece from the magazine 28 or insert it into the magazine 28 . The other workpieces 14' shown are inserted vertically, ie in the vertical direction Z1, into bores in individual magazine pallets 58. In the present case, six magazine pallets 58 are provided, each of which is rectangular in shape and each has twenty bores 60 for inserting the workpieces.

A second workpiece holder 78 is arranged centrally within the tool arrangement 18 , between the first tool spindle 20 and the second tool spindle 24 , opposite the first workpiece holder 12 . In the present case, it is shown partially covered and will be shown in more detail below.

The device 10 comprises the main body 40 and a machine bed as essential bodies on which further components of the device 10 are arranged or formed 66. The base body 40 is essentially cuboid. On it, for example, the second guide carriage 38 is arranged on one side and the workpiece gripper carriage arrangement 54 with the gripper 30 is arranged on another side. The base body 40 and the machine bed 66 are connected to one another close to the ground. The machine bed 66 is designed as an elongated support structure on which the tool arrangement 18, the storage device 69, the second workpiece holder 78 on a first part of the machine bed 66 and the magazine 28 on a second, adjacent part of the machine bed 66 are formed.

FIGS. 2 to 10 shown below sometimes serve to show and explain individual steps of the method according to the invention. The device 10 can be shown in simplified form in these figures in order to show the individual steps of the method in a way that is easy to understand. The same device 10 is shown in each of the individual FIGS. 2 to 10 and the figures build on one another or show successive steps or snapshots of the method.

FIG. 2 shows a detailed view of the device 10 according to the invention according to an exemplary embodiment, the device 10 being shown in a simplified manner in comparison with FIG. The workpiece gripper 30 grips the workpiece 14 with a first workpiece gripper arm 62, the workpiece 14 still being unprocessed, and grips a processed workpiece 14” with a second workpiece gripper arm 64. The workpiece longitudinal axis W is drawn in for the workpiece 14, which—after the workpiece 14 has not yet been clamped—does not yet coincide with the workpiece carriage direction X1. For reasons of simplification, the workpiece gripper 30 is shown floating freely and is therefore shown without being coupled to the base body 40 .

Furthermore, the rotationally drivable workpiece spindle 16 of the first workpiece holder 12 is empty, ie none of the workpieces 14, 14'' and also not the first centering device 44 is stored in the first workpiece holder 12. However, the gripper 42 keeps the first centering device 44 ready and feeds it to the workpiece spindle 16 .

Furthermore, the tool arrangement 18 is shown in FIG. 2, which is however in a standby mode and is not in engagement with any of the workpieces 14, 14'' or is being machined. The first grinding tool 22, which is inserted into the first tool spindle 20, is designed as a grinding wheel. The second grinding tool 26, which is inserted into the second tool spindle 24, is designed as a finishing wheel. The first tool carriage 48 is shown rotated about the tool carriage axis of rotation C1. As can also be seen from Figure 1, a bearing carriage 65 is also arranged on the machine bed 66, which is coupled to the base body 40 as described above, which can be displaced along a bearing carriage arrangement not shown here in a bearing carriage direction X2 relative to the machine bed 66. In turn, three guide columns 67 are arranged on the bearing carriage 65, as will be explained in more detail in connection with FIG. 12a. A support 68 of the bearing device 69 with a bearing trough 70 is formed on the bearing carriage 65 . The storage trough 70 is designed as a V-shaped trough in the support 68 . The support 68 can also be referred to as a bezel. Furthermore, a pressure roller 72 is arranged above the support 68 as part of the bearing device 69 and is rotatably connected at one end to the pressure arm 74 directly connected to the bearing carriage 65 . The pressing arm 74 is coupled at its other end to an actuator 76 which in turn couples the pressing arm 74 to the bearing carriage 65 . The actuator 76 is set up to move the pressing arm 74 in the vertical direction Z1. This makes it possible for the pressure roller 72 to press a workpiece into the bearing trough 70 of the support 68 or release it from it, ie not exerting any pressure on the workpiece. In the present case, the pressure roller 72 is arranged at a distance from the storage trough 70 and no workpiece is arranged in the storage trough 70 or between the pressure roller 72 and the storage trough 70 .

In addition, the second workpiece holder 78 is arranged on the machine bed 66 on a workpiece holder carriage, not shown in detail here, as will be described in more detail in connection with FIG. 12a. The workpiece receiving carriage can be moved in relation to the bearing carriage 65 along a workpiece receiving carriage direction X3. The workpiece receiving carriage with the workpiece holder 78 is displaced on the three guide columns 67 in the process. The guide columns 67 are rigidly coupled to the bearing carriage 65 . The workpiece receiving carriage direction X3 is aligned parallel to the first workpiece carriage direction X1. It is possible by means of the workpiece holding carriage for the second workpiece holding fixture 78 to move away from or approach the first workpiece holding fixture 12 . In addition, as a result, the second workpiece holder 78 can be displaced relative to the tool arrangement 18, even if its distance from the first workpiece holder 12 remains the same. This is particularly relevant when grinding the workpiece 14 . A second centering device 80 is accommodated in the second workpiece holder 78 so as to be freely rotatable about the workpiece axis of rotation A1. The second centering device 80 is arranged on a side of the second workpiece holder 78 facing the first workpiece holder 12 . In addition, the magazine 28 is at least partially shown. FIG. 3 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. Compared to FIG. 2 it can be seen that the first centering device 44 is accommodated in the workpiece spindle 16 of the first workpiece holder 12 . Furthermore, the workpiece 14 is coupled to the first centering device 44 and is centered by the first centering device 44 with respect to the first workpiece axis of rotation A1. The gripper 42 now no longer grips the first centering device 44 because this is surrounded and supported by the workpiece spindle 16 . However, the gripper now grasps the workpiece 14 to hold it in position. The workpiece 14 is no longer held by the workpiece gripper 30 . Instead, the gripper 42 presses a first workpiece end 82 of the workpiece 14 against the first centering device 44. A second workpiece end 84 of the workpiece 14 is floating and not yet coupled to the second centering device 80. The workpiece 14 is thus held in position only by the gripper 42 and the contact with the first centering device 44 .

FIG. 4 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. A state is shown in which the workpiece 14 is coupled to the first centering device 44, as in FIG. 3, and is centered by it. Furthermore, the workpiece 14 is held in position by the gripper 42 and pressed against the first centering device 44 . As in FIG. 3, the second workpiece end 84 is not yet coupled to the second centering device 80 of the second workpiece holder 78 . However, the second workpiece end 84 is about to be coupled with that of the second centering device 80 . For this purpose, the workpiece 14 is displaced via the gripper 42 and the first workpiece holder 12 in the direction of the first workpiece carriage direction X1 by means of the second guide carriage 38 (not shown here). In addition, the bearing slide 65 and the workpiece receiving slide 78 are displaced in the direction of the workpiece spindle 16 (X3 direction).

The workpiece 14 is arranged in the storage trough 70 of the support 68, but above and about 1 to 3 mm from the support 68 at a distance. Thus, no bearing effect is achieved by the support 68 in this method step. The pressure roller 72 is arranged above and also at a distance from the workpiece 14 and thus does not exert any pressure on the workpiece 14 in the direction of the support 68 .

FIG. 5 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment, the pressure roller 72 and the pressure arm 74 being hidden for reasons of better illustration. Compared to Figure 4, the workpiece 14 is not only with the first centering device 44, but now also with the second centering device 80 coupled and is also centered and supported by this about the workpiece axis of rotation A1. The workpiece 14 is thus clamped between the two workpiece holders 12 , 78 .

Compared to FIG. 4, the gripper 42 is now decoupled from the workpiece 14 and also from the first centering device 44 and is in a ready position. The support 68 and the pressure roller 72 (not shown here) are still not in contact with the workpiece 14, as in FIG. The workpiece 14 is thus only stored at its ends by means of the respective centering device 44, 80 in the associated workpiece holder 12, 78.

The workpiece 14 is rotationally driven by the workpiece spindle 16 and rotates about the workpiece axis of rotation A1. The unmachined workpiece 14 is already largely cylindrical in the present case, but does not yet correspond exactly to a cylindrical shape or has a diameter that is too large or unevenness along its lateral surface.

In FIG. 5, the tool arrangement 18 carries out a first grinding machining step. For this purpose, as explained above, the workpiece 14 is driven in rotation. Furthermore, the first grinding tool 22, which is designed as a grinding wheel, is in contact with the workpiece 14 with a lateral surface side 86 of the grinding wheel on the one hand. The grinding wheel has a comparatively high surface roughness. Due to the relative movement and contact between the first abrasive tool 22 and the workpiece 14, material is removed from the workpiece 14.

For the first grinding step, the second grinding tool 26 , which is designed as a finishing wheel, is also driven in rotation about the second tool spindle axis of rotation A3 by means of the second tool spindle 24 . In addition, the second grinding tool 26 on the other side of the first grinding tool 22 is in contact with the workpiece 14. The finishing wheel has a small surface roughness compared with the roughing wheel, but still sufficient for grinding machining. Again, due to the relative movement and contact between the second abrasive tool 26 and the workpiece 14, material is removed from the workpiece 14. FIG. The second grinding tool 26 has a contact area with the workpiece 14 that is further away from the first workpiece holder 12 in the first workpiece carriage direction X1 than the contact area of the first grinding tool 22 with the workpiece 14 is arranged. In addition, the workpiece 14 is displaced in the direction of the first workpiece slide direction X1 in such a way that the workpiece 14 is ground by the two grinding tools 22, 26 along its entire lateral surface, starting from the second workpiece end 84 to the first workpiece end 82. Because of the distance between the two contact areas and the relative movement of the workpiece 14 relative to the grinding tools 22, 26, it is possible for the rough grinding by the grinding wheel to be followed by fine grinding by the finishing wheel.

FIG. 6 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. Compared to FIG. 5, the workpiece 14 was completely ground by means of the first grinding machining step on its entire lateral surface from the second workpiece end 84 to the first workpiece end 82 . The first grinding step is thus now complete and the workpiece 14 is in the form of a cylinder and is therefore rotationally symmetrical with respect to a longitudinal axis of the workpiece, which coincides with the axis of rotation A1 of the workpiece. The two grinding tools 22, 26 are no longer in contact with the workpiece 14.

Before the workpiece 14 is re-clamped, the workpiece diameter is measured along the lateral surface of the workpiece 14. For this purpose, a first measuring device 88, which is designed with two measuring arms 90 arranged parallel to one another and which is arranged on the bearing carriage 65, is connected to the lateral surface of the workpiece 14 contacted. At the same time, the workpiece 14 is displaced relative to the first measuring device 88 in the direction of the first workpiece carriage direction X1 and is driven in rotation about the workpiece axis of rotation A1 by means of the workpiece spindle 16 .

The workpiece diameter is thus measured from the first workpiece end 82 to the second workpiece end 84 along the lateral surface of the workpiece 14 . The measurement can be used to check whether a predetermined workpiece diameter and the rotational symmetry of the workpiece 14 have been achieved. If this is not the case, the first grinding step can be repeated at least for a specific section of the lateral surface of the workpiece 14 .

FIG. 7 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. At least one partial step of the re-clamping of the workpiece 14 is shown. The workpiece 14 is no longer driven in rotation. For this purpose, the first measuring device 88 is again in a ready position and does not touch the workpiece 14 . Compared to FIG. 6, it can be seen that the actuator 76 has pushed the pressure arm 74 downwards and is now moving the workpiece by means of the pressure roller 72. piece 14 is pressed into the storage trough 70. Thus, it is possible to hold the workpiece 14 in position due to the bearing device 69 alone. The workpiece 14 is only coupled to the device 10 by means of the storage device 69 .

Compared to FIG. 6, it can be seen that the two workpiece holders 12, 78 are spaced apart from the workpiece 14. For this purpose, the first workpiece holder 12 with the workpiece 14 was initially moved in the direction of the storage trough 70 (X1 direction). Then the gripper 42 was pivoted to the workpiece 14 so that it grips the workpiece 14 . The workpiece 14 was then separated from the workpiece holder 78 (X3 direction) by a displacement movement thereof, so that the workpiece 14 is initially only held by the first workpiece holder 12 and the gripper 42 . Thereafter, the carriage 32 was lowered in the Z1 direction and thus also the workpiece holder 12 and the gripper 42 until the workpiece made contact with the storage trough 70 . The pressure roller 72 was then brought into contact with the workpiece 14 by actuating the actuator 76, so that the latter is clamped between the bearing trough 70 and the pressure roller. The gripper 42 was then removed from the workpiece and the first workpiece holder 12 was also removed along the first workpiece carriage direction X1 from the workpiece 14 and thus also from the second workpiece holder 78 . Furthermore, the storage device 69 was also shifted (X2 direction) by means of the storage carriage 65 arranged on the machine bed 66, namely in the direction of the first workpiece holder 12. The workpiece is now only held by clamping between the pressure roller 72 and the storage trough 70. Then gripper 42 gripped first centering device 44 and, after there was no longer any contact between first workpiece end 82 and first centering device 44, gripper 42 moved first centering device 44 out of the area between first workpiece end 82 and workpiece spindle 16, thereby moving the first centering device 44 decoupled from the workpiece spindle 16.

FIG. 8 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. Compared to FIG. 7 it can be seen that the workpiece 14 is now re-clamped in the first storage device 12 or in the workpiece spindle 16 . The re-clamping takes place in such a way that the workpiece 14 also contacts the workpiece spindle 16 at least over part of its lateral surface. The workpiece 14 is now stored in the first storage device 12 in such a way that it has a defined position along the workpiece axis of rotation A1 and cannot tilt. In this way, at least slight transverse forces on the workpiece 14 in the direction transverse to the longitudinal axis of the workpiece can be absorbed by the first bearing device 12 without the bearing device 69 exerts a bearing effect on the workpiece 14 . In the present case, the workpiece 14 is not in contact with the bearing device 69 .

Due to the reclamping in the first storage device 12, it is necessary to determine the exact position of the workpiece 14 in the device 10. A second measuring device 94 in the form of a measuring probe is provided on the bearing carriage 65 for this purpose. For this purpose, a measuring head 96 of the measuring device 94 is brought into the vicinity of the second workpiece end 84 , more precisely in a region in front of the second workpiece end 84 . The workpiece 14 is then moved towards the measuring head 96 by means of the guide carriage 38 along the first workpiece carriage direction X1 until the second workpiece end 84 makes contact with the measuring head 96 . The position of the workpiece 14 or the second workpiece end 84 in relation to the first workpiece carriage direction X1 is therefore known, so that grinding can then be carried out on the second workpiece end 84 starting on the lateral surface of the workpiece 14 .

FIG. 9 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. The implementation of the second grinding machining step is shown in FIG. It can be seen that the first grinding machining tool 22 is now rotated counterclockwise by approximately 90 degrees about the tool carriage axis of rotation C1 compared to the first grinding machining step, as viewed from above. This is not absolutely necessary, but enables increased material removal on the workpiece 14.

The workpiece 14 is rotationally driven by the workpiece spindle 16 about the workpiece axis of rotation A1. In addition, the workpiece 14 rests in the storage trough 70 on the support 68 and is pressed into the storage trough 70 by the pressure roller 72 . Compared to the first grinding machining step, the second workpiece end 84 is no longer coupled to the second workpiece holder 78 but is at a distance from it. This allows free machining of the workpiece 14 at the second workpiece end 84. During the second grinding step, both grinding tools 22, 26 contact the workpiece. The second grinding tool 26 in turn has a contact area with the workpiece 14 which, compared to the contact area of the first grinding tool 22 with the workpiece 14, is arranged further away from the first workpiece holder 12 in the first workpiece carriage direction X1. In addition, the workpiece 14 is displaced in the direction of the first workpiece carriage direction X1 in such a way that the workpiece 14 starts along its lateral surface from the second workpiece end 84 to a region near the first workpiece end 82 or a desired region in the direction of the first workpiece end 82 is ground by the two grinding tools 22, 26 (processing length dx1). Because of the distance between the two contact areas and the relative movement of the workpiece 14 relative to the grinding tools 22, 26, it is possible for the rough grinding by the grinding wheel to be followed by fine grinding by the finishing wheel.

In the present case, the two grinding machining tools 22, 26 are moved by means of their respective tool slides 48, 50 in such a way that the workpiece 14 is machined to a predetermined workpiece diameter. In the present case, workpiece 14 is ground to a first workpiece diameter in a section of the lateral surface associated with second workpiece end 84 and to a second workpiece diameter in a section of the lateral surface that adjoins it in the direction of first workpiece end 82, with the first workpiece diameter being smaller than the second workpiece diameter in the present case . This could also be done differently, for example vice versa. This will become even clearer in FIG. 10 below.

In the second grinding step, the workpiece diameter is greatly reduced. At the same time, forces are applied to the workpiece 14 by the abrasive machining tools 22,26. In order to at least partially absorb these forces and to achieve a high machining quality, the bearing device 69 is arranged near the contact areas of the two grinding machining tools 22, 26 during the second grinding machining step. The distance between the contact areas is preferably no more than 10 mm, particularly preferably no more than 5 mm, but at least 0.5 mm, from a contact area of the bearing device 69 with the workpiece 14 . To put it more precisely, the bearing device 69 is arranged in an area between the first workpiece holder 12 and the two grinding machining tools 22 , 26 .

During the second grinding step, the two grinding tools 22, 26 and the bearing device 69 are stationary relative to the machine bed 66 and do not move relative to each other. The workpiece 14 is displaced along the first workpiece carriage direction X1 in the direction of the two grinding machining tools 22, 26 and the storage device 69 by means of the two workpiece holders 12, 78. FIG. 10 shows a further detailed view of the device 10 according to the invention according to an exemplary embodiment. The second grinding step from FIG. 9 is now completely finished. The finished workpiece 14 is now no longer in contact with the two grinding machining tools 22, 26 and the storage device 69, but is merely stored or held by means of the first workpiece holder 12. It can be seen that, as a result of the second grinding machining step, workpiece 14 has a first workpiece diameter in a section of the lateral surface adjacent to second workpiece end 84, i.e. a first workpiece lateral surface 98, which is smaller than a second workpiece diameter which adjoins this section in the direction of the first workpiece end 82 is formed on a further section, that is to say a second workpiece lateral surface 100 on the lateral surface of workpiece 14 . In an area in the workpiece spindle 16 and adjacent thereto, ie a third workpiece lateral surface 102, the workpiece 14 was not machined by means of the second grinding machining step, but is only machined by means of the first grinding machining step.

In order to check the second grinding machining step, the workpiece diameter is now measured again using the first measuring device 88 . For this purpose, a first measuring device 88 with the two measuring arms 90 arranged parallel to one another is brought into contact with the lateral surface of the workpiece 14 . At the same time, the workpiece 14 is displaced relative to the first measuring device 88 in the direction of the first workpiece carriage direction X1 and is driven in rotation about the workpiece axis of rotation A1 by means of the workpiece spindle 16 . The workpiece diameter is thus measured at least in the area of the lateral surface of the workpiece 14 machined by the second grinding machining step. The measurement can be used to check whether a predetermined workpiece diameter and the rotational symmetry of the workpiece 14 have been achieved in the respective sections of the lateral surface. If this is not the case, the second grinding step can be repeated at least for a specific section of the lateral surface of the workpiece 14 .

Another major advantage of the kinematics is the Z1 axis provided. The movements X2, Y1 and Y2 take place relative to the machine bed 66. The first guide carriage 32 (Z1 direction) carries, among other things, the workpiece axis of rotation A1 and the workpiece spindle 16. This makes it possible to move the workpiece 14 to the support 68 after the first grinding step to drive support. A fixed support with high accuracy and rigidity can therefore be used. Furthermore, due to this degree of freedom, a compensation of the wear of the support 68 can be carried out. Furthermore, different workpiece diameters in one Geometry of the support 68 are edited in the second grinding step. To do this, only the first guide carriage (Z1 axis) must be moved accordingly. In the technical implementation, the support 68 is designed with an exchangeable insert.

When the measurement is successfully completed, another workpiece 14' can be ground. For this purpose, another workpiece 14' is already held ready by the workpiece gripper 30. The workpiece can be exchanged as shown in FIG. 2 and the grinding process can be run through again as shown in FIGS.

FIG. 11a shows a sectional view of the first centering device 44 according to a first exemplary embodiment. The first centering device 44 is received in the first workpiece holder 12 over part of its lateral surface and is supported by it. It can be seen that the first workpiece holder 12 includes a clamping device 104 not shown in detail for this purpose. A V-shaped depression 106 is formed on a side of the first centering device 44 that is remote from the first workpiece holder 12, the depression 106 adjoining the lateral surface of the first centering device 44 having a circumferential centering surface 108 arranged obliquely to the lateral surface and a blind hole 110.

FIG. 11a also shows the workpiece 14, which has a circumferential chamfer 112 on its first workpiece end 82. FIG. The workpiece 14 is coupled to a portion of the circumferential centering surface 108 by means of the circumferential chamfer 112, whereby it is supported and centered. The centering shown in more detail in FIG. 11a is also implemented in the exemplary embodiment according to FIGS. For the sake of completeness, it should be made clear that the workpiece 14 is only partially shown on the side facing away from the first workpiece holder 12 for the sake of simplicity.

FIG. 11b shows a sectional view of the first centering device 44 according to a second exemplary embodiment. As in FIG. 11a, the first centering device 44 is received in the first workpiece holder 12 over part of its lateral surface and is supported by it. It can be seen that the first workpiece holder 12 includes a clamping device 104 not shown in detail for this purpose.

A V-shaped tip 114 with a circumferential centering surface 116 is formed on a side of the first centering device 44 facing away from the first workpiece holder 12 . At the first work end 82 of the work piece 14 is a V-shaped Center hole 118 in the middle of the workpiece 14, ie on the workpiece axis W, is formed. The tip 114 engages in the centering hole 118 . The workpiece 14 is thus stored and centered in the first workpiece holder 12 .

FIG. 12a shows a simplified detailed view of the device 10 according to the invention, only individual components of the device 10 being shown. It can be seen that the bearing carriage 65 is coupled by means of a bearing carriage arrangement 120 and can thus be displaced relative to the machine bed 66 in the bearing carriage direction X2. The bearing carriage arrangement 120 comprises at least two rails 121 arranged on the bearing carriage 65 , which are guided in rail guides 123 attached to the machine bed 66 and thus guide the bearing carriage 65 . The assignment of rails 121 and rail guides 123 to bearing slide 65 and machine bed 66 could also be reversed. Furthermore, a screw spindle (not shown) is provided in the bearing carriage assembly 120 for displacing the bearing carriage 65 in the X2 direction.

The three guide columns 67 are attached to the bearing carriage 65, on which in turn the second workpiece holder 78 can be displaced in the workpiece holder carriage direction X3 by means of a workpiece holder carriage 121. The workpiece carriage direction X3 and the bearing carriage direction X2 are arranged parallel to one another. The guide columns 67 are coupled to one another by a stop 122 on the side facing away from the bearing carriage 65 .

An actuator 124 in the form of a pneumatic cylinder is also shown between the guide columns 67 . The actuator 124 can be actuated and thus the second workpiece holder 78 can be displaced on the guide columns 67 in the workpiece holder carriage direction X3. Due to the design of the actuator 124, as will become clear in connection with FIG. As an alternative to the configuration with a pneumatic cylinder, the actuating element 124 can also be implemented, for example, by means of a threaded spindle or a servo drive.

The pressure arm 74 with the pressure roller 72 and the actuator 76 and the support 68 are also arranged on the bearing carriage 65 .

FIG. 12b shows a simplified sectional view of the device 10 according to the invention, the illustration from FIG. 12a being shown in section. In the bearing slide th 65 is a hollow cylinder 126 is formed, wherein the actuator 124 is similar to a piston in the hollow cylinder 126 displaceable. To actuate the actuator 124, a fluid, such as air or oil, can be supplied to the hollow cylinder 126 on the one hand of the piston-like configuration of the actuator 124. Furthermore, a vacuum can be generated in the hollow cylinder 124 .

If a workpiece 14 is to be stored using the two workpiece holders 12 , 78 , the workpiece 14 is first coupled to the first storage device 12 . In this case, the second guide carriage 38 can be displaced along the workpiece carriage direction X1. The workpiece 14 is then coupled to the second bearing device 78 by actuating the actuator 124 . Depending on the workpiece length of the workpiece 14 and the position of the second guide carriage 38 relative to the second carriage guide 39 along the workpiece carriage direction X1, the second workpiece holder 78 can also assume a position between the bearing carriage 65 and the stop 122. With the workpiece 14 inserted, the movement of the second workpiece holder 78 in the workpiece holder carriage direction X3 is dependent on the movement of the second guide carriage 38 in the workpiece carriage direction X1.

FIG. 13a shows a simplified detailed view of the device 10 according to the invention, with the travel paths and the dependencies of the slides being shown in relation to one another in conjunction with FIG. 13b. The workpiece 14 has a machining length dx1. In order to process this length, for example using the first grinding tool 22, the first workpiece holder 12 is displaced in the workpiece carriage direction X1 by the same amount dx1. Furthermore, the storage carriage 65 is displaced by the distance dx2 and the workpiece receiving carriage 121 by the distance dx3. Expressed as a formula, this results in the relationship dx1 = machining length = dx2 + dx3.

Figure 13b shows a simplified detailed view of the device 10 according to the invention, in which, compared to Figure 13a, the first workpiece holder 12 has been moved by the machining length dx1, the bearing carriage 65 by the distance dx2 and the workpiece holder carriage 121 due to the coupling via the workpiece 14 to the first workpiece holder 12 relative to the bearing slide 65 by the distance dx3. In relation to the machine bed 66, the workpiece receiving carriage 121 was also shifted in space by the machining length dx1.

FIGS. 14a and 14b show a simplified detailed view of the device 10 according to the invention, with the second grinding machining step being carried out using an alternative sequence, which can also be referred to as on-the-fly machining. figure 14a represents the beginning of the second grinding step. Contrary to what was described above, the first and the second grinding tool 22, 27--as can be seen from FIG 72, located remotely. In other words, the second grinding step of the workpiece 14 also begins here at the second workpiece end 84 and extends in the direction of the first workpiece end 82, although the bearing device 69 is not arranged in the vicinity of the second workpiece end 84, but in the present case in the vicinity of the first workpiece end 82 or in the vicinity of an area of the workpiece 14 held in the first workpiece holder 12.

Looking at FIGS. 14a and 14b together, it becomes clear that the position of the bearing device 69 in relation to the workpiece 14 and in relation to the first workpiece holder 12 is not changed during the second grinding machining step during on-the-fly machining. Rather, the first workpiece holder 12 in the X1 direction and the bearing slide 65 in the X2 direction are shifted simultaneously, i.e. to the same extent and simultaneously, in the direction of the grinding tools 22, 26 in order to machine the workpiece 14 along the machining length dx1. Thus, the distance between the bearing device 69 and the grinding tools 22, 26 is variable during on-the-fly machining, while it is essentially constant in the second grinding machining step described above.

In the case of on-the-fly machining, too, the workpiece 14 is driven in rotation during the second grinding machining step. In order to also produce geometries on the workpiece 14 that are not rotationally symmetrical, provision can be made for, in particular, oscillating movements of the tools 22, 26 to be carried out via the tool axes Y1 and Y2 synchronously with the rotational movement of the workpiece 14. The rotational speed of the workpiece 14 is preferably not constant, but can also be constant. It can also be provided that the second grinding step is run through several times. This is where one of the strengths of on-the-fly machining becomes clear, because moving the bearing device 69 along the workpiece 14 might be problematic, particularly in the case of asymmetrical workpiece contours, due to different workpiece contours: The bearing device 69 is arranged in an area of the workpiece 14 that is not machined in the second grinding machining step becomes. Of course, it must be taken into account that the bearing effect is reduced due to the larger distance between the tools 22, 26 and the bearing device 69. In the case of on-the-fly processing, the distance between the tools 22, 26 or their areas of engagement with the workpiece 14 and the bearing device 69 or their areas of engagement is therefore preferably in a range between 0.5 and 100 mm.

Claims

29 patent claims

A method of grinding an elongate workpiece (14) comprising the steps of:

- Clamping of the workpiece (14), wherein the workpiece (14) at a first workpiece end (82) by means of a first centering device (44) in a first workpiece holder (12) and at a second workpiece end (84) by means of a second centering device (80) is stored in a second workpiece holder (78); Carrying out a first grinding machining step on at least a first section of a lateral surface of the workpiece (14) by means of a tool arrangement (18);

Re-clamping of the workpiece (14), the workpiece (14) being decoupled from the first and second centering devices (44, 80) and one of the workpiece ends (82, 84) being received in the first workpiece holder (12); and

Carrying out a second grinding step on a second section of the lateral surface of the workpiece (14) using the tool arrangement (18), with a storage device (69) supporting the workpiece (14) over at least a part of the lateral surface of the workpiece (14).

2. The method according to claim 1, wherein during clamping the workpiece (14) via an axial end face of the workpiece (14) and/or a centering in an axial end face of the workpiece (14) and/or a centering in particular on the axial end face of the workpiece (14) adjacent chamfer is coupled to the first centering device (44) and/or via a further axial face and/or a further centering in a further axial face of the workpiece (14) and/or in particular on the further axial face of the workpiece (14) adjacent further bevel is coupled to the second centering device (80).

The method according to claim 1 or 2, wherein the workpiece (14) is ground into a rotationally symmetrical shape at least in the first grinding processing step in the first section; and/or wherein the first section comprises the entire lateral surface of the workpiece (14).

4. The method according to any one of the preceding claims, wherein during the re-clamping the workpiece (14) is mounted via the lateral surface of the workpiece (14) before and/or during the decoupling by means of the bearing device (69), in particular clamped by means of the bearing device (69), becomes; and or 30 wherein a gripper (42) is provided for gripping the first centering device (44), which grips the first centering device (44) during re-clamping and removes it from an area between the first workpiece holder (12) and the first workpiece end (82); and/or wherein the second section is located within the first section or corresponds to the first section; and/or wherein, in particular during the second grinding machining step, the tool arrangement (18) engages with the workpiece (14) offset in the direction of the longitudinal axis (W) of the workpiece (14) relative to an engagement area of the bearing device (69), in particular on one of the first Workpiece holder (12) facing away from the storage device (69).

5. The method according to any one of the preceding claims, wherein during the first and/or second grinding machining step the workpiece (14) is moved in the direction of the workpiece longitudinal axis (W) of the workpiece (14) relative to the bearing device (69); and/or wherein during the second grinding step the bearing device (69) and the tool arrangement (18) are constantly spaced apart from one another.

6. The method according to any one of claims 1 to 4, wherein at least during the second grinding step, the bearing device (69) is arranged at a fixed location on the workpiece (14) with respect to the longitudinal axis (W) of the workpiece, the distance between the bearing device (69 ) and the tool arrangement (18) is varied, particularly preferably reduced, during the second grinding machining step.

7. The method according to any one of the preceding claims, wherein during the second grinding step the tool arrangement (18) is oriented at least partially differently from the first grinding step.

8. The method according to any one of the preceding claims, wherein in the second grinding step, a first workpiece surface (98) is ground to a first workpiece diameter and a second workpiece surface (100) is ground to a second workpiece diameter, the first diameter being smaller than the second diameter and in particular the second workpiece lateral surface (100) is arranged closer to the first workpiece holder (12) than the second workpiece lateral surface (98).

9. The method according to any one of the preceding claims, wherein at least one of the two workpiece holders (12, 78), in particular the first workpiece holder (12), comprises a rotatably drivable workpiece spindle (16) and the workpiece (14) at least during the first and second grinding machining step by means of the rotary-driven workpiece spindle (16) is rotary-driven.

10. The method according to claim 1, wherein after the first grinding step, at least one workpiece diameter is measured in the first section and/or after the second grinding step, at least one workpiece diameter is measured in the second section.

11. The method according to any one of the preceding claims, wherein after the reclamping, a workpiece length, in particular a position of the first or second workpiece end (82; 84), is measured.

12. An apparatus (10) for abrading an elongate workpiece (14) comprising:

- A first workpiece holder (12) for storing the workpiece (14) via a first workpiece end (82) of the workpiece (14) and a second workpiece holder (78) for storing the workpiece (14) via a second workpiece end (84) of the workpiece ( 14);

- a tool assembly (18) for grinding the workpiece (14); and

- A storage device (69) for at least phased storage of the workpiece (14) over at least part of the lateral surface of the workpiece (14); wherein the device is set up to carry out a method according to any one of claims 1 to 11.

13. Device (10) according to claim 12, wherein the storage device (69) is arranged on a storage carriage (65) which can be moved relative to the tool arrangement (18) and relative to the first workpiece holder (12) in the direction of the longitudinal axis (W) of the workpiece is trained.

14. Device (10) according to one of claims 12 or 13, wherein the tool arrangement (18) comprises a first grinding tool (22) and a second grinding tool (26), the first grinding tool (22) being mounted on a first tool carriage (48) and the second grinding tool (26) is arranged on a second tool carriage (50) for moving the grinding tools (22, 26) in a translation direction perpendicular to the longitudinal axis (W) of the workpiece (14) and/or perpendicular to a height direction (Z1); wherein preferably the first and/or the second tool carriage (48, 50) is also arranged on a pivoting device (49) for pivoting the grinding tool (22, 26) about a tool carriage axis of rotation (C1), the tool carriage axis of rotation (C1) being in the height direction ( Z1) is aligned.

15. Device (10) according to one of claims 12 to 14, wherein the device (10) for grinding machining has a guide carriage (38) on which the first workpiece holder (12) is arranged, and a workpiece holder carriage (121) on which the second workpiece holder (78) is arranged, wherein the guide carriage (38) can be moved along a workpiece carriage direction (X1) and the workpiece holder carriage (121) can be moved along a workpiece holder carriage direction (X3).