JP2024533769A - Method and apparatus for grinding elongated workpieces - Google Patents

Abstract

The invention relates to a method for grinding an elongated workpiece (14), comprising the steps of: clamping the workpiece (14) such that the workpiece (14) is supported at a first workpiece end (82) via a first centering device (44) on a first workpiece mount (12) and at a second workpiece end (84) via a second centering device (80) on a second workpiece mount (78); performing a first grinding step by means of a tool unit (18) on at least one first peripheral section of the workpiece (14). - clamping the workpiece (14), during which the workpiece (14) is removed from the first and second centering devices (44, 80) and one of the workpiece ends (82, 84) is attached to the first workpiece mount (12); and - performing a second grinding step by means of the tool unit (18) on a second peripheral section of the workpiece (14), during which a support device (69) supports the workpiece (14) over at least a part of the peripheral surface of the workpiece (14).

Description

The present invention relates to a method and apparatus for grinding elongated workpieces.

The workpiece can be ground in various ways. In the case of rotationally symmetrical elongated workpieces, it is generally necessary to first bring the blank of the workpiece into a rotationally symmetrical shape and then carry out the subsequent grinding process on the workpiece. In order to grind the blank rotationally symmetrically, it is advantageous to support the workpiece over its end faces, so that the entire periphery of the workpiece can be machined freely.

In the case of rotationally symmetric workpieces, in which the ratio of workpiece length to workpiece diameter is particularly large or is large due to the material removal caused by the grinding process and which are to be ground up to the first end of the workpiece, it is known to support the workpiece only at its second end on a workpiece attachment and, in addition, in the vicinity of the tool, on a support over the entire periphery of the workpiece. In this way, the pressure required for the grinding process can be applied to the workpiece by the grinding tool, while at the same time, by supporting it in the vicinity of the tool, sufficient support of the workpiece is ensured, which absorbs the pressure. This makes it possible to avoid deviations from the desired workpiece contour.

A translation of the European patent specification (DE69421859T2) discloses a grinding machine for machining rotationally symmetrical workpieces having a large ratio of workpiece length to workpiece diameter. A spindle supporting one end of the workpiece is supported on the machine bed by a spindle head so as to be movable along the workpiece longitudinal axis relative to two grinding disks located opposite each other. A stationary support is further arranged on the machine bed, which supports the workpiece over its periphery. To grind the rotationally symmetrical workpiece to a preset diameter dimension, the workpiece and the grinding disks are driven in rotation, and the workpiece is moved along the workpiece axis relative to the machine bed and towards the grinding disks via the spindle head.

These various grinding steps described above are typically performed on various grinding machines tailored to each particular grinding step.

However, many of the different grinding devices are associated with high investment costs, which is disadvantageous, especially in the case of relatively small quantities. Furthermore, many of the grinding devices through which the workpieces can pass generally result in long passage durations for the workpieces.

Therefore, there is a need to provide a time-optimized and at the same time easy grinding process for long and narrow workpieces.

This problem is solved by a method according to claim 1. Furthermore, this problem is solved by an apparatus according to claim 12. The dependent claims relate to advantageous refinements of the invention.

The method according to the invention for grinding an elongated workpiece comprises the following steps:
- clamping the workpiece, in which the workpiece is supported at a first workpiece end via a first centering device on a first workpiece mount and at a second workpiece end via a second centering device on a second workpiece mount;
- carrying out a first grinding step on at least one first peripheral section of the workpiece by means of the tool unit; - re-clamping the workpiece, in which the workpiece is removed from the first and second centering devices and one of the workpiece ends is attached to a first workpiece attachment;
- performing a second grinding step on a second peripheral section of the workpiece by means of the tool unit, wherein the support device supports the workpiece over at least a portion of the peripheral surface of the workpiece.

Clamping the workpiece at the workpiece end makes it possible to machine the workpiece flexibly, in particular over the entire circumference of the workpiece. Furthermore, it makes it possible to support the workpiece by the workpiece attachment despite unevenness of the circumference. This means that a workpiece having a workpiece longitudinal axis can be clamped and supported in a simple manner, even if this workpiece initially has a shape that is not rotationally symmetrical with respect to the workpiece longitudinal axis.

The centering device can ensure that the clamped workpiece is in a defined position relative to the workpiece attachment and thus also relative to the tool unit. In other words, the centering device can ensure that the workpiece has a defined workpiece longitudinal axis, to which the rotational symmetry of the workpiece is associated. The workpiece can be rotated around this workpiece longitudinal axis.

The first grinding step allows the desired geometric shape or outer contour to be formed in the first section of the workpiece. In this case, the entire periphery of the workpiece is provided for the first grinding step, since the workpiece is supported via both workpiece ends. The periphery extends between the two workpiece ends. The support device does not engage with or support the workpiece during the first grinding step.

By re-tightening, it is achieved that the workpiece is no longer in contact with the centering device. Furthermore, it is achieved that the workpiece is no longer supported by the second workpiece mount. Depending on the orientation of the workpiece when it is attached to the first workpiece mount, for example, an area of the workpiece circumference arranged corresponding to the second workpiece end can be flexibly processed, as long as the support device does not directly support the workpiece there. This is particularly advantageous for rotationally symmetric workpieces that require processing up to one end of the workpiece. By attaching one workpiece end to the first workpiece mount, a defined support of the workpiece can be achieved. In this case, it can be assumed that the first workpiece mount supports the workpiece in a peripheral engagement in an area of the workpiece circumference arranged corresponding to the first or second workpiece end. This makes it possible to achieve a secure grip or support at the first workpiece mount. That is, after the workpiece circumference has been processed at least in the first section in the first grinding step, the workpiece can be gripped there and thus supported in a defined manner.

Due to the support device, which supports the workpiece during the second grinding step, the workpiece can be processed even if it is relatively elongated. The forces arising from the grinding process can be absorbed via the support device. Deflection of the workpiece can be effectively avoided. This means that even workpieces with a particularly large ratio of workpiece length to workpiece diameter can be processed with high precision.

Overall, the method of the present invention provides efficient grinding of elongated workpieces.

In one refinement of the invention, it may be provided that during clamping, the workpiece is connected to the first centering device via a centering section at one axial end face of the workpiece and/or a chamfer adjacent to the axial end face of the workpiece, and/or to the second centering device via another centering section at another axial end face of the workpiece and/or a chamfer adjacent to the axial end face of the workpiece. This can be achieved such that the entire circumferential surface of the workpiece can be machined substantially or completely freely. At the same time, the workpiece is supported in a defined manner. During clamping, it is advantageous if the two end faces are arranged parallel to one another. If this is not the case, it may be provided that the end faces of the workpiece are machined in a preceding machining step, so that the end faces are parallel to one another. "Axial direction" in relation to the workpiece generally means the direction of the longitudinal axis of the workpiece.

In one aspect of the invention, it may be provided that during the first grinding step, the first workpiece mount of the tool unit approaches at a first speed. In this way, simple machining can be achieved along the first section. Alternatively, it may be provided that during the first grinding step, the first workpiece mount of the tool unit moves away at a first speed.

In one configuration of the invention, it may be envisaged that during the first grinding step, the first support device of the tool unit approaches at a second speed.

In one aspect of the invention, it may be envisaged that the second speed is lower than the first speed, whereby the support device gradually approaches the first workpiece attachment portion.

In one refinement of the invention, it may be envisaged that the first and/or second grinding steps include peel grinding.

In one aspect of the invention, it may be provided that the workpiece is ground to a rotationally symmetric shape in at least the first section during the first grinding step. The rotational symmetry is relative to the longitudinal axis of the workpiece. This is advantageous for the subsequent grinding process and allows the workpiece to be mounted in a defined manner on the first workpiece mount during re-tightening.

In one embodiment of the invention, it may be envisaged that the first section includes the entire periphery of the workpiece, i.e., complete grinding of the periphery of the workpiece can be achieved in the first grinding step. This facilitates handling, subsequent grinding steps and subsequent storage.

In one aspect of the invention, it may be provided that during refastening, the workpiece is supported by the support device via its periphery before and/or during removal, in particular clamped by the support device. This allows a defined position of the workpiece during refastening to be achieved. Clamping prevents the workpiece from undesirably tipping or slipping off. The workpiece can be held securely.

In one refinement of the invention, it may be envisaged that a gripper is provided for gripping the first centering device, which grips the first centering device during refastening and moves it away from the area between the first workpiece mount and the first workpiece end. In other words, it may be sufficient that a translational movement along a given axis is required between the first workpiece mount and the workpiece relative to each other. This allows a simple and time-saving refastening to be achieved overall.

In one embodiment of the invention, it may be provided that the second section is located within the first section or corresponds to the first section. This allows for the second grinding step to be achieved by machining a peripheral area of the workpiece that has already been machined in the first grinding step.

In one refinement of the invention, it may be provided that, in particular during the second grinding step, the tool unit engages the workpiece in the direction of the workpiece longitudinal axis of the workpiece with respect to the engagement area of the support device, in particular on the side of the support device opposite the first workpiece attachment. This offset allows a large engagement area on the workpiece for supporting the tool to be achieved. At the same time, the grinding process is not carried out at the place where the support device simultaneously supports the workpiece. This ensures reliable support by the support device. It may be provided that the offset with respect to the workpiece length is small, for example 1/20, 1/30 or 1/40. This makes it possible that forces that are well or short-distance transmitted to the workpiece due to the grinding process can be absorbed by the support device. Deformations or deflections of the workpiece due to the grinding process can be avoided or at least reduced. The goal is to process the workpiece with the tool unit as close as possible to the support device.

In the present invention, it may be envisaged that during the first and/or second grinding steps, the workpiece is moved relative to the support device in the direction of the workpiece's longitudinal axis. In this case, the workpiece may be supported on the support device so as to be slidable or gliding in the direction of the workpiece's longitudinal axis at least during the second grinding step.

In one refinement of the invention, it may be provided that during the second grinding step, the support device and the tool unit are spaced apart from each other at a constant distance.

Alternatively, in one aspect of the invention, it may be provided that during at least the second grinding step, the support device is arranged at the workpiece in a fixed position relative to the workpiece longitudinal axis. In this case, the support device moves simultaneously with the first workpiece mounting part in the direction of the workpiece longitudinal axis.

In one refinement of the alternative embodiment, it may be envisaged that the distance between the support device and the tool unit is changed, preferably reduced, during the second grinding step. Overall, the alternative configuration allows so-called cantilevered machining, in which the workpiece length to be machined can be freely accessed during the second grinding step without being influenced by the support device. This is particularly advantageous when forming a non-rotationally symmetric profile or contour on the workpiece and/or when the second grinding step is repeated several times.

In one aspect of the invention, it may be provided that during the second grinding step, the tool unit is at least partially oriented differently compared to the first grinding step, i.e., a different type of grinding can be achieved compared to the first grinding step, even though, for example, the same machining tool or tools are engaged with the workpiece.

In one refinement of the invention, it may be provided that in the second grinding step, the first peripheral surface area is ground to a first work diameter and the second peripheral surface area is ground to a second work diameter, the first diameter being smaller than the second diameter. In this case, it may be provided that the second peripheral surface of the work is located closer to the first work mount than the second peripheral surface of the work. It may also be provided that the third, fourth, etc. peripheral surfaces of the work are ground to corresponding diameters. All or some of the diameters may be different. It may be provided that the diameters decrease or increase with distance from the first work mount.

In one further aspect of the invention, it may be provided that in the second grinding step, a variable diameter is formed in the region of the first workpiece periphery, in particular a diameter that is constant along the workpiece longitudinal axis or a diameter that varies according to a predetermined function.

In one refinement of the invention, it may be provided that at least one of the two workpiece mounts, in particular the first workpiece mount, has a rotatably driven workpiece spindle, and the workpiece is rotatably driven by the workpiece spindle, which is rotatably driven at least during the first and second grinding steps. The rotatable drive is performed around the longitudinal axis of the workpiece.

In one aspect of the invention, it may be envisaged that after the first grinding step, at least one measurement of the workpiece diameter in the first section is performed and/or after the second grinding step, at least one measurement of the workpiece diameter in the second section is performed. This allows checking whether the workpiece has reached a predetermined dimension. If not, it may be envisaged, for example, to repeat the first or second grinding step.

In one refinement of the invention, it may be envisaged that the measurement is repeated at least once and, optionally, the first grinding step is repeated until the workpiece reaches the predetermined dimensions.

In one aspect of the invention, it may be further provided that after re-tightening, a measurement of the workpiece length, in particular the position of the first or second workpiece end, is performed. Whether the position of the first or second workpiece end is measured depends on the orientation of the workpiece attached to the first workpiece attachment. In other words, it is advantageous to measure the position of the workpiece end opposite the first workpiece attachment. This may be necessary in order to perform the second grinding step with high accuracy and to start the second grinding step immediately at the first or second workpiece end.

The above-mentioned measurements may be performed by each measuring device or by one common measuring device, in particular a measuring probe.

The above-described method and/or the above-described improvements of the method can advantageously be implemented in a single apparatus, in particular a grinding apparatus.

In one refinement of the invention, it may be provided that the elongated workpiece has a non-rotationally symmetric shape at least in the second section after the second grinding step, preferably resulting in a non-rotationally symmetric shape of the elongated workpiece by the second grinding step. In this case, it may be provided that the elongated workpiece has a polygonal, elliptical or another complex shape after the second grinding step. This may be carried out in particular by a movement of the workpiece relative to the tool unit, which is coordinated with respect to one another in the direction of the workpiece longitudinal axis.

Furthermore, the subject of the invention is a device for grinding elongated workpieces, which device comprises:
a first workpiece mount supporting the workpiece via a first workpiece end of the workpiece and a second workpiece mount supporting the workpiece via a second workpiece end of the workpiece;
- a tool unit for grinding the workpiece;
- a support device for supporting the workpiece in at least a stepped manner over at least a portion of its periphery,
The solution is provided by an apparatus, which is configured to perform a method according to one of the above mentioned approaches.

The workpiece mounts each and also together allow support of the workpiece via the workpiece end of the workpiece. In this case, support via the workpiece end means that the workpiece may be connected to the respective workpiece mount directly or via an intermediate part, for example via a centering device.

In one refinement of the invention, it may be provided that the support device has a rest with a support recess. The support recess can be used to support the workpiece but still allow movement of the workpiece in the direction of the workpiece longitudinal axis relative to the support device. To improve the sliding of the workpiece relative to the support recess, the support recess can be made of or coated with a material having a low coefficient of friction.

In one further configuration of the invention, it may be provided that the support is height adjustable perpendicular to the longitudinal axis of the workpiece in the height direction, i.e. the support device can support workpieces of different diameters.

In one embodiment of the invention, it is provided that the support device further comprises a pressing device, in particular a pressing roller, arranged opposite the support part, in which case the support device supports the workpiece between the support part and the pressing device. The pressing device can ensure that the workpiece remains securely on the support part, in particular in the support recess. The pressing roller further allows the workpiece to perform a rotational movement relative to the support device while being supported.

In one refinement of the invention, it may be provided that the support device is arranged on a support carriage, which is configured to be movable in the support carriage direction relative to the tool unit and relative to the first workpiece mount. In this case, the support carriage direction may correspond to the workpiece longitudinal axis at least during the first or second grinding step. The mobility makes it possible to simply replenish the workpiece via the support device and to simply support it during the second grinding step.

In one configuration of the invention, it may be envisaged that the tool unit has a first rotatably drivable tool spindle with a first grinding tool and a second rotatably drivable tool spindle with a second grinding tool.

In this case, the present invention may provide that the first grinding tool has a roughing disc and/or the second grinding tool has a finishing disc.

This allows for a variety of grinding processes, particularly with different roughnesses.

Furthermore, the present invention may assume that the workpiece is positioned between the first grinding tool and the second grinding tool during grinding.

It may further be provided in the present invention that during the first and/or second grinding steps, the contact area of the first grinding tool with the workpiece is located closer to the first workpiece mount than the contact area of the second grinding tool with the workpiece with the first workpiece mount. That is, the respective contact points are arranged offset with respect to the longitudinal axis of the workpiece. In this way, in cooperation with the relative movement of the workpiece with respect to the tool unit, the first grinding process can be performed by the first grinding tool and the second subsequent grinding process can be performed by the second grinding tool. Overall, such an efficient grinding process of the workpiece can be achieved. This is particularly advantageous when the first grinding tool is formed as a roughing disk and the second grinding tool is formed as a finishing disk.

In one refinement of the invention, it may be provided that the first grinding tool is arranged on a first tool carriage and the second tool is arranged on a second tool carriage, which moves the tool in a translation direction perpendicular to the workpiece longitudinal axis and perpendicular to the height direction. In this way, the grinding tool can be easily adapted to wear on the grinding tool or material removal on the workpiece.

In one embodiment of the invention, it may be further provided that the first and/or second tool carriage is arranged on a pivoting device for pivoting the grinding tool about a tool carriage rotation axis, the tool carriage rotation axis being oriented in the height direction, i.e. perpendicular to the workpiece longitudinal axis and perpendicular to the translation direction. This allows the first or second grinding tool to engage the workpiece in various orientations.

In this case, in one refinement of the invention, it may be provided that during the second grinding step, the first grinding tool is arranged pivoted about the first pivot axis by a predetermined angle compared to the first grinding step.

In one refinement of the invention, the grinding apparatus may further include a work magazine for storing the workpiece and a work gripper, where the work gripper is configured to transfer the workpiece between the work magazine and a position between the workpiece mounting portions.

In this case, in one refinement, it can be provided that the work gripper has at least two work gripper arms for gripping the workpiece. This makes it possible for the work gripper to hold, for example, the workpiece to be processed in one work arm and at the same time lift up the processed workpiece in the other work arm.

In one aspect of the invention, it may be envisaged that the grinding device has a guide carriage on which a first workpiece mounting part is arranged and a workpiece mounting carriage on which a second workpiece mounting part is arranged, in which the guide carriage is movable along a workpiece carriage direction and the workpiece mounting carriage is movable along a workpiece mounting carriage direction. The workpiece carriage direction and the workpiece mounting carriage direction may be parallel or identical to each other. This allows the workpiece mounting part to grip workpieces of different lengths. Furthermore, various positions of the workpiece relative to the grinding tool are possible.

In one refinement, it may be provided that the first workpiece mount is arranged on a carriage that allows the first workpiece mount to be moved in the height direction. In this case, the height direction is preferably oriented perpendicular to the longitudinal axis of the workpiece or perpendicular to the workpiece carriage direction. This means that even if the support is not arranged to be movable in the height direction, workpieces of different diameters can be processed in the grinding device during the second grinding step. Alternatively or additionally, the second workpiece mount may also be arranged on another such carriage.

In one refinement of the invention, the grinding apparatus further comprises a control unit for controlling the apparatus.

It should be noted that generally, features, configurations or advantages of the invention described in relation to the method also apply to the apparatus. That is, method features may be realized by the apparatus and may in particular be embodied in apparatus features, without the need to explicitly describe these apparatus features. The same also applies in reverse to apparatus features and vice versa.

The present invention will now be further described with reference to the accompanying drawings.

1 is a perspective view of an apparatus according to the present invention, according to one embodiment; FIG. 2 is a perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another detailed view of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 shows another perspective detail of the device according to the invention, according to one embodiment. FIG. 2 is a cross-sectional view of the centering device according to the first embodiment. FIG. 4 is a cross-sectional view of a centering device according to a second embodiment. FIG. 2 is a simplified detailed view of the device according to the invention; 1 is a simplified cross-sectional view of an apparatus according to the present invention; FIG. 2 is a simplified detailed view of the device according to the invention; FIG. 2 is a simplified detailed view of the device according to the invention; FIG. 2 is a simplified detailed view of an apparatus according to the invention for performing one grinding step in a modified manner. FIG. 2 is a simplified detailed view of an apparatus according to the invention for performing a modified grinding step;

1 shows a diagram of an apparatus 10 according to the invention for grinding according to an embodiment. The apparatus 10 has a first workpiece mount 12, on which a workpiece 14 is mounted and which comprises a rotatably drivable workpiece spindle 16 supporting the workpiece 14. The apparatus 10 further comprises a tool unit 18 with a first rotatably drivable tool spindle 20 in which a first grinding tool 22 is arranged, and a second rotatably drivable tool spindle 24 in which a second grinding tool 26 is arranged. The apparatus 10 further comprises a support device 69, which is only partially visible here and is shown partially obscured by the tool unit 18. A pressure roller 72 provided on a pressure arm 74 is visible as part of the support device 69. The support device 69 will be explained in more detail in connection with another drawing. The apparatus 10 further comprises a magazine 28 with further workpieces 14'. The device 10 further includes a work gripper 30.

The first work mounting portion 12 is disposed on a first guide carriage 32, which is disposed so as to be movable along two rails 36 of a first carriage guide 34 in a height direction Z1. A second guide carriage 38 is also formed on the first carriage guide 34, and the second guide carriage 38 is disposed so as to be movable along a second carriage guide 39 formed on a base 40 of the device 10. In other words, the first carriage guide 34, together with the first work mounting portion 12, is movable via the second guide carriage 38 and the second carriage guide 39 along a first work carriage direction X1. The first work carriage direction X1 coincides with the work longitudinal axis W when the work 14 is attached to the work mounting portion 12.

A gripper 42 for gripping the first centering device 44 or the workpiece 14 is further arranged on the first workpiece mounting part 12. The gripper 42 is configured to insert the first centering device 44 into the workpiece spindle 16 of the first workpiece mounting part 12 and to remove it from the workpiece spindle 16. For this purpose, the gripper 42 can be rotated about a rotation axis C2 extending in the height direction Z1 via a gripper actuator 46. Furthermore, the gripper 42 is connected to the first workpiece mounting part 12 by a gripper carriage unit 47. The gripper carriage unit 47 enables the movement of the gripper 42 on the first workpiece mounting part 12 along a gripper carriage direction X5 arranged parallel to the first workpiece carriage direction X1. The gripper 42 further has a manipulable gripper tong 43 with which the gripper 42 grips the first centering device 44 or the workpiece 14.

The rotatably driven work spindle 16 is configured to rotate the work 14 about the work rotation axis A1. The work rotation axis A1 extends parallel to the first work carriage direction X1.

The tool unit 18 includes a first tool carriage 48, in which a first tool spindle 20 is formed, and the first tool carriage 48 is movable in a first tool carriage direction Y2 relative to the base body 40. The first tool carriage direction Y2 is arranged perpendicular to the height direction Z1 and perpendicular to the first work carriage direction X1. The tool unit 18 further includes a second tool carriage 50, in which a second tool spindle 24 is arranged, and the second tool carriage 50 is movable in a second tool carriage direction Y1 relative to the base body 40 independently of the first tool carriage 48. The second tool carriage direction Y1 is arranged parallel to the first tool carriage direction Y2.

The first tool carriage 48 can furthermore be swiveled by the swiveling device 49 about a tool carriage rotation axis C1 relative to the base body 40, where the tool carriage rotation axis C1 is oriented parallel to the height direction Z1 and 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 rotation axis A2 arranged perpendicular to the tool carriage rotation axis C1. When the first tool carriage 48 rotates, the orientation of the first tool spindle rotation axis A2 can be changed in space relative to the base body 40. In this embodiment, the first tool spindle rotation axis A2 is arranged parallel to the first workpiece carriage direction X1. The second tool spindle 24 drives the second grinding tool 26 about a second tool spindle rotation axis A3 arranged parallel to the first workpiece carriage direction X1 in this embodiment.

The work gripper 30 is coupled to the base body 40 via a joint unit 52 in the work gripper carriage unit 54. The joint unit 52 enables the work gripper 30 to be pivoted relative to the work gripper carriage unit 54 about the work gripper pivot axis B1. The work gripper pivot axis B1 is arranged parallel to the two tool carriage directions Y2, Y1 or perpendicular to the height direction Z1 and the work carriage direction X1. The work gripper carriage unit 54 enables the movement of the work gripper 30 relative to the base body 40 in a direction Z2 parallel to the height direction Z1 and in one further direction Y3. The further direction Y3 is arranged parallel to the tool carriage directions Y2, Y1 or perpendicular to the height direction Z1 and the work carriage direction X1.

The magazine 28 is arranged on a magazine carriage unit 56, which is configured 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. Via the magazine carriage unit 56, the magazine 28 can be positioned relative to the workpiece gripper 30, so that the workpiece gripper 30 can remove the workpiece from the magazine 28 or insert it into the magazine 28. In the present embodiment, the illustrated further workpiece 14' is inserted vertically, i.e. in the height direction Z1, into the holes of the individual magazine pallets 58. In the present embodiment, six magazine pallets 58 are provided, each of which is rectangular and has 20 holes 60 for inserting the workpieces.

A second workpiece mount 78 is located centrally within the tool unit 18, between the first tool spindle 20 and the second tool spindle 24, opposite the first workpiece mount 12. The second workpiece mount 78 is shown partially obscured in this embodiment and will be described in more detail below.

The device 10 includes a base 40 and a machine bed 66 as main bodies on which the other components of the device 10 are arranged or formed. The base 40 is formed substantially in the shape of a rectangular parallelepiped. The base 40 has, for example, a second guide carriage 38 arranged on one side and a work gripper carriage unit 54 with a gripper 30 arranged on the other side. The base 40 and the machine bed 66 are connected to each other near the bottom. The machine bed 66 is formed as an elongated support structure in which the tool unit 18, the support device 69 and the second workpiece mounting 78 are formed in a first part of the machine bed 66 and the magazine 28 is formed in an adjacent second part of the machine bed 66.

FIGS. 2-10 described below may be used to illustrate and explain the individual steps of the method according to the invention. In this case, the device 10 may be illustrated in a simplified form in these figures in order to easily and clearly illustrate the individual steps of the method. The same device 10 is shown in each of the individual figures 2-10, and these figures are arranged so as to overlap each other or show successive steps or snapshots of the method.

2 shows a detailed view of the device 10 according to the invention according to one embodiment, which is shown in a simplified form compared to FIG. 1. The work gripper 30 grips the workpiece 14 with the first work gripper arm 62, which is not yet processed, and grips the processed workpiece 14'' with the second work gripper arm 64. A workpiece longitudinal axis W is drawn for the workpiece 14, which does not yet coincide with the workpiece carriage direction X1, since the workpiece 14 has not yet been clamped. For reasons of simplifying the drawing, the work gripper 30 is shown as free-floating and thus without a connection to the base body 40.

Furthermore, the rotatably drivable work spindle 16 of the first workpiece mount 12 is empty, i.e. neither the workpiece 14, 14'' nor the first centering device 44 is supported on the first workpiece mount 12. However, the gripper 42 holds the first centering device 44 in a standby state and supplies the first centering device 44 to the work spindle 16.

2 further shows the tool unit 18, which is in a standby mode and is not engaged with or processing any of the workpieces 14, 14''. The first grinding tool 22 inserted in the first tool spindle 20 is formed as a roughing disk. The second grinding tool 26 inserted in the second tool spindle 24 is formed as a finishing disk. The first tool carriage 48 is shown rotated about the tool carriage rotation axis C1.

1, a support carriage 65 is further arranged on the machine bed 66 connected to the base body 40 as described above, which can be moved along a support carriage unit (not shown in detail here) in a support carriage direction X2 relative to the machine bed 66. Three guide posts 67 are also arranged on the support carriage 65, as will be explained in more detail in connection with FIG. 12a. A support carriage 65 is formed with a support recess 70 for a support device 69. The support recess 70 is formed as a V-shaped recess in the support carriage 68. The support carriage 68 is sometimes called a steady rest. Furthermore, a pressure roller 72 is arranged on the upper side of the support carriage 68 as part of the support device 69, which is rotatably connected to a pressure arm 74 which is directly connected at one end to the support carriage 65. The pressing arm 74 is connected at its other end to an actuator 76, which also connects the pressing arm 74 to the support carriage 65. The actuator 76 is configured to move the pressing arm 74 in the height direction Z1. This allows the pressing roller 72 to press the workpiece into the support recess 70 of the placement section 68 or to release it from the support recess 70, i.e., not apply pressure to the workpiece. In this embodiment, the pressing roller 72 is disposed at a distance from the support recess 70, and no workpiece is disposed in the support recess 70 or between the pressing roller 72 and the support recess 70.

12a, the second workpiece mount 78 is arranged on a workpiece mount carriage (not shown in detail here). The workpiece mount carriage is movable relative to the support carriage 65 along the workpiece mount carriage direction X3. In this case, the workpiece mount carriage with the workpiece mount 78 is moved on three guide posts 67. The guide posts 67 are rigidly connected to the support carriage 65. The workpiece mount carriage direction X3 is oriented parallel to the first workpiece carriage direction X1. Via the workpiece mount carriage, the second workpiece mount 78 can be moved away from the first workpiece mount 12 or closer to the first workpiece mount 12. This also allows the second workpiece mount 78 to be moved relative to the tool unit 18, even if the distance of the second workpiece mount 78 to the first workpiece mount 12 remains unchanged. This is particularly important when grinding the workpiece 14. A second centering device 80 is attached to the second workpiece mounting portion 78 so as to be freely rotatable about the workpiece rotation axis A1. The second centering device 80 is arranged on the side of the second workpiece mounting portion 78 facing the first workpiece mounting portion 12. Furthermore, the magazine 28 is at least partially shown.

3 shows another detailed view of the device 10 according to the invention according to one embodiment. Compared to FIG. 2, it can be seen that the first centering device 44 is attached to the work spindle 16 of the first workpiece mount 12. Furthermore, the workpiece 14 is connected to the first centering device 44 and is centered by the first centering device 44 with respect to the first workpiece rotation axis A1. The gripper 42 no longer grips the first centering device 44, since the first centering device 44 is supported by the work spindle 16 in circumferential engagement. However, the gripper grips the workpiece 14 in order to hold it in place. The workpiece 14 is no longer held by the work gripper 30. Instead, the gripper 42 presses the first workpiece end 82 of the workpiece 14 against the first centering device 44. The second workpiece end 84 of the workpiece 14 is free floating and is not yet connected to the second centering device 80. That is, the workpiece 14 is held in place only by the gripper 42 and contact with the first centering device 44.

Figure 4 shows another detailed view of the device 10 according to the invention according to one embodiment. In this case, the workpiece 14 is shown to be connected to the first centering device 44 as shown in Figure 3 and is centered by the first centering device 44. The workpiece 14 is then held in position by the gripper 42 and pressed against the first centering device 44. As in Figure 3, the second workpiece end 84 has not yet been connected to the second centering device 80 of the second workpiece mount 78. However, the second workpiece end 84 is about to be connected to the second centering device 80. For this purpose, the workpiece 14 is moved in the first workpiece carriage direction X1 by the second guide carriage 38 (not shown) via the gripper 42 and the first workpiece mount 12. Furthermore, the support carriage 65 and the workpiece mount carriage 78 are moved in the direction of the workpiece spindle 16 (direction X3).

The workpiece 14 is arranged in the support recess 70 of the support portion 68, but at a distance of approximately 1 to 3 mm above the support portion 68. This means that no support is provided by the support portion 68 in this method step. The pressure roller 72 is arranged above the workpiece 14, also at a distance, and thus does not apply pressure to the workpiece 14 towards the support portion 68.

Figure 5 shows another detailed view of the device 10 according to the invention according to one embodiment, where the pressure roller 72 and the pressure arm 74 have been omitted for reasons of better illustration. In comparison with Figure 4, the workpiece 14 is not only connected to the first centering device 44, but also to the second centering device 80, by which it is also centered and supported about the workpiece rotation axis A1. That is to say, the workpiece 14 is clamped between the two workpiece mountings 12, 78.

Compared to FIG. 4, the gripper 42 is now in a standby position, removed from the workpiece 14 and from the first centering device 44. The rest 68 and the pressure roller 72 (not shown here) are still not in contact with the workpiece 14, as in FIG. 4. That is, the workpiece 14 is supported only at its two ends on the corresponding workpiece mounts 12, 78 via the respective centering devices 44, 80.

The workpiece 14 is driven to rotate by the workpiece spindle 16 and rotated about the workpiece rotation axis A1. In this embodiment, the unmachined workpiece 14 is already formed to be approximately cylindrical, but does not yet correspond exactly to a cylindrical shape or has an excessively large diameter or has irregularities along its circumferential surface.

The tool unit 18 performs a first grinding step in FIG. 5. For this purpose, the workpiece 14 is driven in rotation as described above. Furthermore, a first grinding tool 22 formed as a rough cutting disk contacts the workpiece 14 on one side with the circumferential side 86 of the rough cutting disk. Furthermore, the first grinding tool 22 is driven in rotation by the first tool spindle 20 about the first tool spindle rotation axis A2. The rough cutting disk has a relatively high surface roughness. Due to the relative movement and contact between the first grinding tool 22 and the workpiece 14, material is removed from the workpiece 14.

For the first grinding step, a second grinding tool 26 formed as a finishing disk is further rotated by the second tool spindle 24 about the second tool spindle rotation axis A3. Furthermore, the second grinding tool 26 contacts the workpiece 14 on a different side than the first grinding tool 22. The finishing disk has a smaller surface roughness than the roughing disk, but still sufficient for grinding. Due to the relative movement and contact between the second grinding tool 26 and the workpiece 14, material is also removed from the workpiece 14. The second grinding tool 26 has a contact area with the workpiece 14, which is arranged further away from the first workpiece mount 12 in the first workpiece carriage direction X1 than the contact area of the first grinding tool 22 with the workpiece 14. Furthermore, the workpiece 14 is moved in the first workpiece carriage direction X1, so that the workpiece 14 is ground along its entire circumference by the two grinding tools 22, 26, starting from the second workpiece end 84 to the first workpiece end 82. Due to the distance between the two contact areas and the relative movement of the workpiece 14 with respect to the grinding tools 22, 26, it can be achieved that the rough grinding by the rough cutting disk is followed by the fine grinding by the finishing disk.

Figure 6 shows another detailed view of the device 10 according to the invention according to one embodiment. In comparison with Figure 5, the workpiece 14 has been completely ground in the first grinding step from the second workpiece end 84 to the first workpiece end 82 over the entire circumference of the workpiece 14. Thus, the first grinding step is now completed and the workpiece 14 is cylindrical and thus rotationally symmetrical with respect to the workpiece longitudinal axis, which coincides with the workpiece rotation axis A1. The two grinding tools 22, 26 are no longer in contact with the workpiece 14.

Before the workpiece 14 is re-tensioned, a measurement of the workpiece diameter is performed along the periphery of the workpiece 14. For this purpose, a first measuring device 88 formed with two measuring arms 90 arranged parallel to one another and arranged on the support carriage 65 is brought into contact with the periphery of the workpiece 14. At the same time, the workpiece 14 is moved in the first workpiece carriage direction X1 relative to the first measuring device 88 and is driven in rotation about the workpiece rotation axis A1 by the workpiece spindle 16. As a result, the workpiece diameter is measured along the periphery of the workpiece 14 from the first workpiece end 82 to the second workpiece end 84. This measurement makes it possible to check whether the preset workpiece diameter and rotational symmetry of the workpiece 14 have been achieved. If not, the first grinding step can be repeated at least for a specific section of the periphery of the workpiece 14.

Figure 7 shows another detailed view of the device 10 according to the invention according to one embodiment. In this case, at least one partial step of the step of re-clamping the workpiece 14 is shown. The workpiece 14 is now no longer driven in rotation. For this purpose, the first measuring device 88 is again in the waiting position and is not in contact with the workpiece 14. It can be seen, in comparison with Figure 6, that the actuator 76 has pushed the pressure arm 74 downwards and the workpiece 14 is now pressed into the support recess 70 by the pressure roller 72. This makes it possible to hold the workpiece 14 in position only by the support device 69. The workpiece 14 is connected to the device 10 only via the support device 69.

6, it can be seen that both workpiece mounting parts 12, 78 are separated from the workpiece 14. For this purpose, the first workpiece mounting part 12 together with the workpiece 14 is first moved in the direction of the support recess 70 (X1 direction). The gripper 42 is then rotated toward the workpiece 14, so that the gripper 42 grips the workpiece 14. The workpiece 14 is then moved away from the workpiece mounting part 78 by the movement of the workpiece mounting part 78 (X3 direction), so that the workpiece 14 is first held only by the first workpiece mounting part 12 and the gripper 42. The carriage 32 is then lowered in the Z1 direction until the workpiece comes into contact with the support recess 70, and thus the workpiece mounting part 12 and the gripper 42 are also lowered. Next, the actuator 76 is actuated to bring the pressing roller 72 into contact with the workpiece 14, so that the workpiece 14 is sandwiched between the support recess 70 and the pressing roller. The gripper 42 is then removed from the workpiece, and the first workpiece mount 12 is then moved away from the workpiece 14 and thus away from the second workpiece mount 78 along the first workpiece carriage direction X1. The support device 69 is then moved in the same way, i.e. toward the first workpiece mount 12 (X2 direction), by the support carriage 65 arranged on the machine bed 66. That is, the workpiece is now only held by being pinched between the pressure roller 72 and the support recess 70. The gripper 42 then engages the first centering device 44 circumferentially, and once there is no longer any contact between the first workpiece end 82 and the first centering device 44, the gripper 42 moves the first centering device 44 out of the area between the first workpiece end 82 and the workpiece spindle 16, thereby disengaging the first centering device 44 from the workpiece spindle 16.

8 shows another detailed view of the device 10 according to the invention according to one embodiment. Compared to FIG. 7, it can be seen that the workpiece 14 is now clamped on the first support device 12 or on the workpiece spindle 16. In this case, the workpiece 14 is clamped on the workpiece spindle 16 at least over a part of its circumference. The workpiece 14 is now supported on the first support device 12, so that the workpiece 14 has a defined position along the workpiece rotation axis A1 and does not tilt. In this way, at least minor transverse forces acting on the workpiece 14 transverse to the workpiece longitudinal axis can be absorbed by the first support device 12 without the support device 69 exerting a supporting effect on the workpiece 14. In this embodiment, the workpiece 14 does not come into contact with the support device 69.

Based on the clamping at the first support device 12, it is necessary to determine the exact position of the workpiece 14 in the device 10. For this purpose, a second measuring device 94 is provided in the form of a measuring probe on the support carriage 65. For this purpose, the measuring head 96 of the measuring device 94 is brought in the vicinity of the second workpiece end 84, more precisely in the area in front of the second workpiece end 84. The workpiece 14 is then moved by the guide carriage 38 towards the measuring head 96 along the first workpiece carriage direction X1 until the second workpiece end 84 comes into contact with the measuring head 96. As a result, the position of the workpiece 14 or the second workpiece end 84 in relation to the first workpiece carriage direction X1 is known, so that the grinding process on the periphery of the workpiece 14 can then be carried out starting from the second workpiece end 84.

In FIG. 9, another detailed view of the device 10 according to the invention is shown according to one embodiment. In this case, FIG. 9 shows the performance of the second grinding step. It can be seen that the first grinding tool 22 has now been rotated counterclockwise as viewed from above by about 90 degrees about the tool carriage rotation axis C1 compared to the first grinding step. This is not essential, but allows for improved material removal at the workpiece 14.

The workpiece 14 is driven to rotate around the workpiece rotation axis A1 by the workpiece spindle 16. Furthermore, the workpiece 14 is placed on the support portion 68 in the support recess 70 and is pressed into the support recess 70 by the pressing roller 72. The second workpiece end 84 is no longer connected to the second workpiece mounting portion 78 compared to the first grinding step and is spaced apart from the second workpiece mounting portion 78. This allows free machining of the workpiece 14 at the second workpiece end 84. During the second grinding step, both grinding tools 22, 26 come into contact with the workpiece. The second grinding tool 26 also has a contact area with the workpiece 14, which is located further away from the first workpiece mounting portion 12 in the first workpiece carriage direction X1 compared to the contact area between the first grinding tool 22 and the workpiece 14. Furthermore, the workpiece 14 is moved in the first workpiece carriage direction X1, so that the workpiece 14 is ground along its periphery by both grinding tools 22, 26 starting from the second workpiece end 84 to a region near the first workpiece end 82 or to a desired region toward the first workpiece end 82 (machining length dx1). Due to the distance between the two contact areas and the relative movement of the workpiece 14 with respect to the grinding tools 22, 26, it can be achieved that the rough grinding by the rough cutting disk is followed by the fine grinding by the finishing disk.

In this embodiment, both grinding tools 22, 26 are moved by the respective tool carriages 48, 50, so that the workpiece 14 is machined to a preset workpiece diameter. In this embodiment, the workpiece 14 is machined to a first workpiece diameter in a peripheral section arranged corresponding to the second workpiece end 84, and to a second workpiece diameter in a peripheral section following this in the direction of the first workpiece end 82, where in this embodiment the first workpiece diameter is smaller than the second workpiece diameter. This can also be done in another way, for example vice versa. This will become even clearer in the following FIG. 10.

In the second grinding step, the workpiece diameter is significantly reduced. At the same time, a force is applied to the workpiece 14 by the grinding tools 22, 26. In order to at least partially absorb this force and achieve a high processing quality, the support device 69 is arranged in the vicinity of the contact area of the two grinding tools 22, 26 during the second grinding step. In this case, the contact area is preferably spaced apart from the contact area of the support device 69 with the workpiece 14 by no more than 10 mm, particularly preferably no more than 5 mm, but at least 0.5 mm. More precisely, the support device 69 is arranged in the area between the first workpiece mount 12 and the two grinding tools 22, 26.

During the second grinding step, both grinding tools 22, 26 and the support device 69 are stationary with respect to the machine bed 6 and do not undergo any relative movement. The workpiece 14 is moved by both workpiece mounts 12, 78 along the first workpiece carriage direction X1 toward both grinding tools 22, 26 and the support device 69.

10 shows another detailed view of the device 10 according to the invention according to one embodiment. The second grinding step shown in FIG. 9 has now been completely completed. The completely machined workpiece 14 is no longer in contact with the two grinding tools 22, 26 and the support device 69, but is supported or held only by the first workpiece mount 12. It can be seen that, due to the second grinding step, the workpiece 14 has a first workpiece diameter smaller than the second workpiece diameter in the peripheral section adjacent to the second workpiece end 84, i.e., in the first workpiece peripheral surface 98, and that the second workpiece diameter is formed next to this section in another peripheral section of the workpiece 14, i.e., in the second workpiece peripheral surface 100, towards the first workpiece end 82. In the area of the work spindle 16 and the area adjacent to the work spindle 16, i.e., the third work peripheral surface 102, the workpiece 14 is not machined by the second grinding step, but is only machined by the first grinding step.

Then, to check the second grinding step, a measurement of the workpiece diameter is again carried out by the first measuring device 88. For this purpose, the first measuring device 88 with two measuring arms 90 arranged parallel to one another is brought into contact with the circumferential surface of the workpiece 14. At the same time, the workpiece 14 is moved in the first workpiece carriage direction X1 relative to the first measuring device 88 and is driven in rotation about the workpiece rotation axis A1 by the workpiece spindle 16. This allows the workpiece diameter to be measured at least in the circumferential surface area of the workpiece 14 machined by the second grinding step. This measurement makes it possible to check whether the preset workpiece diameter and rotational symmetry of the workpiece 14 have been achieved in each circumferential surface section. If not, the second grinding step can be repeated at least for a specific section of the circumferential surface of the workpiece 14.

Another important advantage of the kinematics is that the Z1 axis is provided. The movements X2, Y1 and Y2 take place relative to the machine bed 66. The first guide carriage 32 (Z1 direction) supports, among other things, the workpiece rotation axis A1 and the workpiece spindle 16. This allows the workpiece 14 to be moved towards the supporting rest 68 after the first grinding step. This means that a stationary mounted rest with high precision and rigidity can be used. Furthermore, this freedom allows compensation for wear of the rest 68 to be carried out. Furthermore, different workpiece diameters can be processed in the second grinding step at a defined geometry of the rest 68. For this, only the first guide carriage (Z1 axis) needs to be moved accordingly. In a technical implementation, the rest 68 is formed with an exchangeable insert.

Once the measurement has been successfully completed, another workpiece 14' can be ground. For this purpose, the workpiece 14' is already held by the workpiece gripper 30. The workpiece exchange can be carried out as shown in FIG. 2, and the grinding method can be carried out again as shown in FIGS. 2 to 10.

11a shows a cross-sectional view of the first centering device 44 according to the first embodiment. In this case, the first centering device 44 is attached to the first workpiece mount 12 over a portion of its circumferential surface and is supported by the first workpiece mount 12. It can be seen that for this purpose, the first workpiece mount 12 has a fastening device 104 (not shown in detail). On the side of the first centering device 44 facing away from the first workpiece mount 12, a V-shaped recess 106 is formed, which has a centering surface 108 adjacent to the circumferential surface of the first centering device 44 that extends in the circumferential direction and is arranged obliquely relative to the circumferential surface, and a blind hole 110.

11a also shows the workpiece 14, which in this case has a circumferentially extending chamfer 112 at its first workpiece end 82. The workpiece 14 is connected via the circumferentially extending chamfer 112 to a portion of the circumferentially extending centering surface 108, by which the workpiece 14 is supported and centered. The centering shown more precisely in FIG. 11a is also realized in the embodiment shown in FIGS. 1 to 10. For the sake of completeness, it should be made clear that the workpiece 14 is only partially shown on the side opposite the first workpiece mounting part 12 for reasons of easier illustration.

11b shows a cross-sectional view of the first centering device 44 according to the second embodiment. As in FIG. 11a, the first centering device 44 is attached to the first workpiece mount 12 over a portion of its periphery and is supported by the first workpiece mount 12. It can be seen that for this purpose the first workpiece mount 12 has a clamping device 104 (not shown in detail).

The first centering device 44 is formed with a V-shaped tip 114 having a circumferentially extending centering surface 116 on the side opposite the first workpiece mounting portion 12. A V-shaped centering hole 118 is formed in the first workpiece end 82 of the workpiece 14 at the center of the workpiece 14, i.e., on the workpiece axis W. The tip 114 engages in the centering hole 118. This allows the workpiece 14 to be supported and centered on the first workpiece mounting portion 12.

12a shows a simplified detailed view of the device 10 according to the invention, where only the individual components of the device 10 are shown. It can be seen that the support carriage 65 is connected via a support carriage unit 120 and thus can be moved in a support carriage direction X2 relative to the machine bed 66. The support carriage unit 120 comprises at least two rails 121 arranged on the support carriage 65, which are guided in rail guides 123 attached to the machine bed 66 and thus guide the support carriage 65. The corresponding arrangement of the rails 121 and the rail guides 123 relative to the support carriage 65 and the machine bed 66 may also be reversed. Furthermore, a threaded spindle (not shown) may be provided in the support carriage unit 120 to move the support carriage 65 in the X2 direction.

Three guide posts 67 are attached to the support carriage 65, and the second work mounting portion 78 can also move on these guide posts 67 in the work mounting carriage direction X3 via the work mounting carriage 121. The work carriage direction X3 and the support carriage direction X2 are arranged parallel to each other. The guide posts 67 are connected to the stopper 122 on the side opposite the support carriage 65.

Between the guide posts 67, an actuating mechanism 124 in the form of a pneumatic cylinder is further shown. The actuating mechanism 124 can be operated and thus can move the second workpiece attachment 78 on the guide posts 67 in the workpiece attachment carriage direction X3. In this case, as will become clear further in conjunction with FIG. 12b, due to the configuration of the actuating mechanism 124, it can only be moved without a clamped workpiece 14 to an end position on the guide posts 67, that is, to abutment against the support carriage 65 or the stop 122. As an alternative to the configuration with a pneumatic cylinder, the actuating mechanism 124 can also be realized, for example, by a threaded spindle or a servo drive.

The support carriage 65 further includes a pressing arm 74 equipped with a pressing roller 72, an actuator 76, and a mounting portion 68.

12b shows a simplified detailed view of the device 10 according to the invention, in which the view shown in FIG. 12a is shown in section. A hollow cylinder 126 is formed in the support carriage 65, in which the actuating mechanism 124 is movable in the same way as a piston. To operate the actuating mechanism 124, on the one hand, the hollow cylinder 126 of the piston-like arrangement of the actuating mechanism 124 can be supplied with a fluid, such as air or oil. Furthermore, a vacuum can also be formed in the hollow cylinder 124.

When the workpiece 14 is to be supported by both workpiece mounting parts 12, 18, the workpiece 14 is first connected to the first workpiece mounting part 12. At this time, the second guide carriage 38 may be moved along the workpiece carriage direction X1. Then, the actuation mechanism 124 is operated to connect the workpiece 14 to the second workpiece mounting part 78. 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 mounting part 78 can also occupy a position between the support carriage 65 and the stopper 122. With the workpiece 14 inserted, the movement of the second workpiece mounting part 78 in the workpiece mounting carriage direction X3 depends on the movement of the second guide carriage 38 in the workpiece carriage direction X1.

Figure 13a shows a simplified detailed view of the device 10 according to the invention, in which the travel distances and dependencies of the carriages relative to one another are shown in conjunction with Figure 13b. The workpiece 14 has a machining length dx1. To machine this length, for example with the first grinding tool 22, the first workpiece mount 12 is moved in the workpiece carriage direction X1 by the same value dx1. Furthermore, the support carriage 65 is moved by a distance dx2 and the workpiece mount carriage 121 is moved by a distance dx3. Expressed as a formula, the relationship dx1 = machining length = dx2 + dx3 is therefore obtained.

Figure 13b shows a simplified detailed view of the device 10 according to the invention, where, compared to Figure 13a, the first workpiece mount 12 has been moved by the machining length dx1, the support carriage 65 has been moved by a distance dx2, and the workpiece mount carriage 121 has been moved by a distance dx3 relative to the support carriage 65, based on its connection to the first workpiece mount 12 via the workpiece 14. Relative to the machine bed 66, the workpiece mount carriage 121 has likewise been moved in space by the machining length dx1.

14a and 14b show a simplified detailed view of the device 10 according to the invention, but in this case the second grinding step is carried out in an alternative procedure, sometimes called cantilever processing. In this case, in FIG. 14a the start of the second grinding step is shown. In contrast to the above, the first and second grinding tools 22, 27 are arranged at the start of the second grinding step away from the support device 69, i.e. away from the rest 68 and the pressing roller 72, as can be seen in FIG. 14a. In other words, the second grinding step of the workpiece 14 also starts in this case from the second workpiece end 84 and proceeds in the direction of the first workpiece end 82, but the support device 69 is not arranged near the second workpiece end 84, but in this case near the first workpiece end 82 or near the area of the workpiece 14 attached to the first workpiece attachment 12.

14a and 14b together, it becomes clear that the position of the support device 69 relative to the workpiece 14 and the first workpiece mount 12 during the second grinding step is not changed during cantilever machining. Rather, the first workpiece mount 12 is moved in the X1 direction and the support carriage 65 is moved in the X2 direction in common, i.e. to the same extent and simultaneously, toward the grinding tools 22, 26, so that the workpiece 14 is machined along the machining length dx1. Thus, the distance of the support device 69 relative to the grinding tools 22, 26 is variable during cantilever machining, while it is substantially constant during the above-mentioned second grinding step.

In the case of cantilever machining, the workpiece 14 is also driven in rotation during the second grinding step. In order to also produce non-rotationally symmetrical geometric shapes in the workpiece 14, it may be assumed that the oscillating movement of the tools 22, 26 is carried out synchronously with the rotational movement of the workpiece 14, in particular via the tool axes Y1 and Y2. In this case, the rotation speed of the workpiece 14 is preferably not constant, but may also be constant. In this case, it may also be assumed that the second grinding step is carried out several times. Here, one of the advantages of cantilever machining becomes apparent, since in the case of asymmetrical workpiece contours, the movement of the support device 69 along the workpiece 14 may be problematic due to the different workpiece contours. That is, the support device 69 is arranged in the area of the workpiece 14 that is not machined in the second grinding step. Of course, it must be taken into account that the support effect is reduced due to the greater distance of the tools 22, 26 to the support device 69. Therefore, preferably, in the case of cantilever machining, the distance between the engagement area of the tool 22, 26 or the tool 22, 26 with the workpiece 14 and the engagement area of the support device 69 or the support device 69 is within the range of 0.5 to 100 mm.

Claims (15)

A method for grinding an elongated workpiece (14), comprising the steps of:
- clamping the workpiece (14) in such a way that the workpiece (14) is supported at a first workpiece end (82) via a first centering device (44) on the first workpiece mount (12) and at a second workpiece end (84) via a second centering device (80) on the second workpiece mount (78);
- carrying out a first grinding step on at least one first peripheral section of said workpiece (14) by means of a tool unit (18),
- a re-clamping step of the workpiece (14), during which the workpiece (14) is removed from the first and second centering devices (44, 80) and one of the workpiece ends (82, 84) is attached to the first workpiece mounting part (12);
- performing a second grinding step on a second peripheral section of the workpiece (14) by means of the tool unit (18), wherein a support device (69) supports the workpiece (14) over at least a portion of the peripheral surface of the workpiece (14). The method according to claim 1, wherein, during tightening, the workpiece (14) is connected to the first centering device (44) via one axial end face of the workpiece (14) and/or a centering portion at one axial end face of the workpiece (14) and/or a chamfer adjacent to the axial end face of the workpiece (14) and/or to the second centering device (80) via another axial end face of the workpiece (14) and/or another centering portion at another axial end face of the workpiece (14) and/or a chamfer adjacent to the other axial end face of the workpiece (14). 3. The method according to claim 1 or 2, wherein the workpiece (14) is ground into a rotationally symmetric shape in the first section during at least the first grinding step, and/or the first section includes the entire circumferential surface of the workpiece (14). During the refastening, the workpiece (14) is supported by the supporting device (69) via the circumferential surface of the workpiece (14) before and/or during the dismounting, in particular clamped by the supporting device (69), and/or a gripper (42) is provided which grips the first centering device (44) during the refastening and moves it away from the area between the first workpiece mounting part (12) and the first workpiece end (82), and/or the second section is arranged within or corresponds to the first section, and/or in particular during the second grinding step, the tool unit (18) engages the workpiece (14) in the direction of the workpiece longitudinal axis (W) of the workpiece (14) with respect to the engagement area of the support device (69), in particular on the side of the support device (69) opposite the first workpiece mount (12);
4. The method according to claim 1 , During the first and/or the second grinding step, the workpiece (14) is moved relative to the support device (69) in the direction of the workpiece longitudinal axis (W) of the workpiece (14), and/or during the second grinding step, the support device (69) and the tool unit (18) are spaced apart from each other at a constant distance.
5. The method according to any one of claims 1 to 4. The support device (69) is arranged in a fixed position on the workpiece (14) with respect to the workpiece longitudinal axis (W) at least during the second grinding step;
Preferably, the distance between the support device (69) and the tool unit (18) is changed, particularly preferably decreased, during the second grinding step.
5. The method according to any one of claims 1 to 4. The method according to any one of claims 1 to 6, wherein during the second grinding step, the tool unit (18) is at least partially oriented differently compared to the first grinding step. The method according to any one of claims 1 to 7, wherein in the second grinding step, the first workpiece peripheral surface (98) is ground to a first workpiece diameter and the second workpiece peripheral surface (100) is ground to a second workpiece diameter, the first workpiece diameter being smaller than the second workpiece diameter, in particular the second workpiece peripheral surface (100) being located closer to the first workpiece mounting portion (12) than the first workpiece peripheral surface (98). The method according to any one of claims 1 to 8, wherein at least one of the two workpiece mountings (12, 78), in particular the first workpiece mounting (12), has a rotatably driven workpiece spindle (16), and the workpiece (14) is rotatably driven by the workpiece spindle (16), which is rotatably driven at least during the first and second grinding steps. The method according to any one of claims 1 to 9, wherein after the first grinding step, at least one measurement of the workpiece diameter in the first section is performed, and/or after the second grinding step, at least one measurement of the workpiece diameter in the second section is performed. The method according to any one of claims 1 to 10, further comprising the step of measuring the workpiece length, in particular the position of the first or second workpiece end (82; 84), after the re-tightening. An apparatus (10) for grinding an elongated workpiece (14), comprising:
a first work mounting portion (12) supporting the work (14) via a first work end (82) of the work (14) and a second work mounting portion (78) supporting the work (14) via a second work end (84) of the work (14);
a tool unit (18) for grinding said workpiece (14),
- a support device (69) for supporting the workpiece (14) at least in stages over at least a portion of its periphery,
The device is configured to carry out a method according to any one of claims 1 to 11.
Apparatus (10). The device (10) according to claim 12, wherein the support device (69) is arranged on a support carriage (65), which is configured to be movable in the direction of the workpiece longitudinal axis (W) relative to the tool unit (18) and relative to the first workpiece mounting portion (12). The tool unit (18) includes a first grinding tool (22) and a second grinding tool (26);
the first grinding tool (22) is arranged on a first tool carriage (48) and the second grinding tool (26) is arranged on a second tool carriage (50) which moves the grinding tools (22, 26) in a translation direction perpendicular to a workpiece longitudinal axis (W) of the workpiece (14) and/or perpendicular to a height direction (Z1);
Preferably, the first and/or the second tool carriage (48, 50) is further arranged on a swivel device (49) for swiveling the grinding tool (22, 26) about a tool carriage rotation axis (C1), the tool carriage rotation axis (C1) being oriented in the height direction (Z1).
14. Apparatus (10) according to claim 12 or 13. The grinding device (10) has a guide carriage (38) on which the first workpiece mounting portion (12) is arranged, and a workpiece mounting carriage (121) on which the second workpiece mounting portion (78) is arranged, the guide carriage (38) is movable along a workpiece carriage direction (X1), and the workpiece mounting carriage (121) is movable along a workpiece mounting carriage direction (X3), as described in any one of claims 12 to 14.

Images