EP3135433A2 - Surface processing unit, machine tool and method of operating - Google Patents

Abstract

The invention relates to a peripheral surface processing unit (10) for finish machining workpiece peripheral surfaces (72) eccentric to a workpiece axis (116) by means of at least one finishing tool, wherein the at least one finishing tool is held on a finishing tool holder (60) and wherein the finishing tool holder (60) Bearing unit during machining of a workpiece peripheral surface (72) along a movement path of the workpiece peripheral surface (72) is movable, wherein the peripheral surface processing unit (10) comprises an oscillation drive (48) by means of which the finishing tool holder (60) is oscillated in a direction parallel to the workpiece axis direction , The invention further relates to a machine tool and method for operating a peripheral surface processing unit (10) and a machine tool.

Description

The invention relates to a peripheral surface processing unit for finish machining workpiece peripheral surfaces eccentric to a workpiece axis by means of at least one finishing tool, wherein the at least one finishing tool is held on a finishing tool holder, and wherein the finishing tool holder is movable by a bearing unit during machining of a workpiece peripheral surface along a movement path of the workpiece peripheral surface.

Such a peripheral surface processing unit is made of EP 2 617 522 B1 known.

During finishing, a workpiece is driven in rotation by means of a rotary drive, so that the workpiece peripheral surface to be machined also rotates. This rotational movement is superimposed on a relative to the workpiece axis directed relative movement between the workpiece and the finishing belt by the workpiece is reciprocated with an oscillating drive in parallel to the workpiece axis direction. As a result, the workpiece peripheral surface is provided with a characteristic for the finishing process cross-cut structure.

The workpiece peripheral surfaces to be machined are, in particular, bearing surfaces of crankshafts or camshafts. These storage areas must be manufactured with a high dimensional accuracy. In particular, the bearing surfaces of the crankshafts or camshafts should be made so that they ensure in conjunction with the bearing surfaces of a crankcase or camshaft housing or with the bearing surfaces of a connecting rod possible backlash-free and low-friction bearings with high wing fractions.

It has been found that the setup effort for preparing the finishing machining of workpieces of a workpiece lot is relatively high. In mass production, this is acceptable; In small series, however, this leads to high costs per workpiece. Moreover, the investment cost for providing a machine tool equipped with peripheral surface processing units is relatively high, so that amortization is difficult for smaller companies with a higher degree of specialization.

On this basis, the present invention is based on the object, a peripheral surface processing unit to provide, which is particularly well suited for the finishing machining of workpieces small workpiece lots.

This object is achieved in a peripheral surface processing unit of the aforementioned type according to the invention that the peripheral surface processing unit has an oscillating drive, by means of which the finishing tool holder is driven to oscillate in a direction parallel to the workpiece axis direction.

The peripheral surface processing unit according to the invention has an oscillation drive which oscillates the finish tool holder. In this way, a finishing tool cooperating with the finishing tool holder, in particular a finishing belt or a finishing stone, can be driven in an oscillating manner. Compared to a conventional oscillation drive in which the workpiece is reciprocated in a direction parallel to the workpiece axis, a relatively small and relatively compact oscillation drive can be used. In particular, it is not necessary to oscillate a whole of the headstock, workpiece and tailstock in a direction parallel to a workpiece axis.

By generating an oscillating motion on the peripheral surface processing unit itself, it can be used in conjunction with very simply constructed machine tools. These machine tools can be very compact because they only need a workpiece holder with a rotary drive.

By providing an oscillating drive which drives the finish tool holder, a workpiece to be machined can rest in a direction parallel to the workpiece axis. This also has the advantage that viewed along the workpiece axis parallel to each other staggered workpiece peripheral surfaces can be processed independently. In particular, it is also possible to simultaneously process a plurality of workpiece peripheral surfaces, if a part of the workpiece peripheral surfaces to be machined is not to be finish-machined (for example, a sealing seat of a crankshaft).

In a particularly preferred embodiment it is provided that the oscillation drive between the bearing unit and the finishing tool holder is effective. This means that the oscillation drive is arranged on the bearing unit and oscillates the finishing tool holder. In this way, during operation of the peripheral surface processing unit, only the finish tool holder and the finish tool cooperating with the finish tool holder are set in an oscillating motion. Thus, the oscillating masses can be reduced to the smallest possible degree.

A further preferred embodiment provides that the oscillation drive comprises an eccentric unit. Such an eccentric unit allows a simple translation of a rotational movement in an oscillatory motion. The rotational movement can be generated with a simple drive motor, which cooperates via a rotating shaft with the eccentric unit.

In a further preferred embodiment it is provided that the processing unit comprises a carrier unit, on which a first bearing part of the bearing unit is displaceably mounted, wherein the first bearing part has a pivotable together with this pivot bearing, wherein on the pivot bearing a pivotable relative to the first bearing part second Bearing part of the bearing unit is mounted, wherein the oscillation drive and the finishing tool holder are arranged on the two bearing part. In this arrangement, the carrier unit forms a frame of the peripheral surface processing unit. Starting from this frame, a linear guide for a first bearing part of the bearing unit is initially provided relative to the carrier unit. On the first bearing part, a jointly with this slidable pivot bearing is provided, so that the pivotability of a second bearing part of the above-mentioned linear mobility of the first bearing part follows kinematically. This has the advantage that during the processing of a non-concentric to a workpiece axis workpiece peripheral surface, ie during processing, for example, a crank bearing a crankshaft, a distance between the finishing tool holder and the finishing tool on the one hand and the pivot axis on the other hand remains constant. In this way, the product of an oscillating frictional force between the workpiece and finishing tool and from a defined by the distance between the finishing tool and the pivot axis lever arm (ie acting on the pivot bearing bending moment) remains constant.

For a configuration of the bearing unit described above, it is preferred if a linear drive is arranged on the carrier unit, by means of which the first

Bearing part is displaceable along a rectilinear path. This allows positioning of the finish tool holder and a finishing tool relative to a workpiece without having to provide corresponding machine tool side positioning devices. The linear drive does not pivot during machining of a workpiece peripheral surface that is eccentric to a workpiece axis, but remains in a constant spatial position.
It is particularly preferred if the linear drive is effective as a pressing device for setting a pressing force with which presses the at least one finish train against a finish end to be machined workpiece peripheral surface. A preferred example of such a linear drive is a pneumatic cylinder. A linear drive, which is also effective as a pressing device, so can be used simultaneously as a positioning and provide a pressing force. When machining an eccentric to a workpiece axis workpiece peripheral surface allows a pneumatic cylinder and the provision of a length compensation movement.

As an alternative to the configuration described above (in which a first bearing part of the bearing unit is displaceably mounted on a carrier unit, the first bearing part has a pivot bearing which is displaceable together with the second bearing part of the bearing unit which is pivotable relative to the first bearing part on the pivot bearing ), it is possible to pivotally support the first bearing part about a pivot axis on the carrier unit, and to store a second bearing part slidably on the first bearing part. In this case, a linear drive between the first bearing part and the second bearing part is effective; of the Linear drive is pivoted together with the first bearing part about the pivot axis. This arrangement has the advantage that a contact force generated by the linear drive can always be introduced perpendicular to a workpiece surface to be finish-finished.

The peripheral surface processing unit according to the invention is also particularly flexible used when the finishing tool is designed as a finishing tape and when the storage unit, in particular on a second bearing part of the storage unit, a storage device for fresh finishing tape and / or a collector device for collecting spent finishing tape is or are arranged. In this way, the peripheral surface processing unit is also self-sufficient with respect to the supply of finishing tape and does not have to be matched with components of an external finishing tape management.

In the event that the finishing tool is designed as a finishing belt, it is particularly preferred if the peripheral surface processing device has a finishing belt drive which is designed as a traction drive and supplies a fresh finishing belt section to the finish tool holder by pulling on a worn finishing belt section. In this way, a particularly simple trained finishing belt drive can be provided, in which the finishing belt can be kept in a particularly simple manner "under tension".

In particular, it is advantageous if the finishing tool holder and the finishing tool are designed such that they allow the machining of workpiece peripheral surfaces with different diameters. In this way, the scope of the The circumferential surface treatment unit according to the invention is further expanded. This can be used in particular to arrangements that from the EP 2 803 445 A1 or the DE 10 2014 200 445 A1 or the DE 10 2014 213 194 A1 the applicant are known.

Particularly advantageous in connection with the above-mentioned diameter-flexible finish tool holders is also an optional finish tape storage device which stores an additional portion of the finish tape when the finishing tape is out of contact with a workpiece and releases the additional portion of the finish tape when the finishing tape is in contact with the workpiece arrives. Thus, the storage device provides an additional portion of the finishing tape which is released when the finishing strip, preferably just taut prior to contact with a workpiece, conforms to the contour of a finishing tool holder.

It is particularly advantageous for the peripheral surface processing unit according to the invention, which is designed for the finishing machining of workpiece surfaces which are eccentric to a workpiece axis and has corresponding degrees of freedom of movement, optionally also used for finish machining of a workpiece peripheral surface of a workpiece which is concentric with a workpiece axis. This may be, for example, the main bearings of a crankshaft or a camshaft. The circumferential surface processing unit according to the invention thus provides the kinematic conditions to be able to machine eccentric workpiece peripheral surfaces to a workpiece axis, but can be used as needed to be concentric with a workpiece axis

To process workpiece peripheral surfaces. In this way, the range of application of the peripheral surface processing unit according to the invention is further increased.

A separate peripheral surface processing unit, which is designed exclusively for machining concentric to a workpiece axis workpiece peripheral surfaces, so the orbital path of an eccentric workpiece peripheral surface can not follow, thus need not be kept on a machine tool. Rather, it is possible within the scope of the present invention that the above-described peripheral surface processing unit is successively used both for finishing machining of a workpiece peripheral surface eccentric to a workpiece axis and finishing machining of workpiece peripheral surface concentric with a workpiece axis.

The present invention has the further object of providing a machine tool which is particularly well suited for the finishing machining of workpieces small workpiece lots.

This object is achieved in a machine tool in that it comprises a peripheral surface processing unit of the type described above and a workpiece holder for holding a workpiece, and at least a first positioning device for positioning the peripheral surface processing unit, in particular a support of the peripheral surface processing unit, relative to the workpiece. In particular, the positioning device has a positioning axis parallel to the workpiece axis Direction to, alternatively or additionally thereto, a feed axis in the direction perpendicular to the workpiece axis direction.

The machine tool further comprises a workpiece holder with a rotary drive for driving the workpiece about the workpiece axis, wherein preferably the workpiece is held immovably in a direction parallel to the workpiece axis direction in the workpiece holder. In this way, can be dispensed with a large-scale and heavy oscillation drive, with which, for example, a headstock, a tailstock and a workpiece as a whole are driven to oscillate.

Furthermore, it is preferred if the machine tool has at least one second positioning device for positioning an axial surface processing unit for finishing machining of surfaces of a surface pair that are perpendicular to a workpiece axis. Such an axial surface processing unit may also be referred to as a "passport bearing unit". For the second positioning device, it is likewise preferred if this has a positioning axis in a direction parallel to the workpiece axis, alternatively or in addition to this, a feed axis in a direction perpendicular to the workpiece axis.

In a particularly preferred axial surface processing unit is provided that it has two separate finishing tapes, which each serve for processing only one surface of the two surfaces of a surface pair. In a conventional axial surface processing unit only a finishing belt is used, which is first supplied to one surface of the two surfaces of a pair of surfaces, then deflected and then supplied to a second surface of the surface pair. In such a conventional axial surface working unit, the feed of finishing belt must be indexed to prevent a finishing belt already worn on the first surface from being fed after its deflection to the second surface. Such indexing is not required in the axial surface processing unit according to the invention. In this two separate finishing tapes are provided, which are each associated with only one surface of a pair of surfaces. Each finishing belt is thus used exclusively for one of the two surfaces of the surface pair. Thus, the finishing tapes can be tracked individually and without indexing.
It is understood that the above-described Axialflächenbearbeitungseinheit taken alone and independent of a peripheral surface processing unit is advantageous and can also constitute an invention per se.

The invention further relates to a method for operating a previously described peripheral surface processing unit or a machine tool described above. These methods help to be able to use the peripheral surface processing unit according to the invention flexibly, so that workpieces of small workpiece lots can be machined with economic finish.

According to a first method of the invention, a force with which the at least one finishing tool presses against a workpiece peripheral surface to be finished is set by adjusting the position of the at least one finishing tool along a rectilinear path. Advantageously, the Adjusting the position by means of a pneumatic cylinder mentioned above, which generates a contact pressure. This pneumatic cylinder also provides length compensation movability.

According to a further method of the invention, the peripheral surface processing unit is reciprocated in a direction parallel to the workpiece axis during finishing machining of a workpiece peripheral surface and the oscillating movement of the at least one finishing tool. In this way, a Überlagerungshub can be realized, which makes it possible to finish with a finishing tool of a certain width Werkstückumfangsflächen finish, which have a greater width. The overlay stroke then serves to be able to travel the entire width of a workpiece peripheral surface to be machined, without requiring replacement or adaptation of the finishing tool and / or the finish tool holder. In this case, the potential disadvantage of a higher processing time for finishing machining a certain workpiece peripheral surface is accepted in favor of the fact that the peripheral surface processing unit according to the invention can be used for a large number of differently wide workpiece peripheral surfaces.

According to another method of the present invention, in the same chucking of a workpiece using the same peripheral surface processing unit, successively different workpiece peripheral surfaces of the same workpiece are finish-machined. The different workpiece peripheral surfaces may be a plurality of workpiece peripheral surfaces having the same geometry have, so for example, two crank bearings of the same crankshaft. However, the different workpiece peripheral surfaces may also be workpiece circumferential surfaces which have a different geometry, that is, for example, a crank bearing and a main bearing of the same crankshaft. It is essential that specialized machining units do not have to be maintained to process a specific bearing geometry. Rather, a circumferential surface processing unit according to the invention is kept in stock, which processes different workpiece circumferential surfaces one after the other at the expense of the machining time. In this way, even small series can be realized economically, in which it does not matter that a machine tool is maximally utilized, but that with a low equipment use and with acceptable set-up workpieces, which have different geometries, can be edited.

The different workpiece circumferential surfaces can be, for example, main bearings, connecting rod bearings and / or sealing seats of a crankshaft or compressor shaft or about shaft bearings and cam surfaces of a camshaft. Such a camshaft may, for example, be the camshaft of a valve drive or else an eccentric shaft which has at least one eccentric section arranged eccentrically with respect to a shaft axis.

Fig. 1

eine perspektivische Ansicht einer Ausführungsform einer Umfangsflächenbearbeitungseinheit aus einer ersten Perspektive;

Fig. 2

eine perspektivische Ansicht der Umfangsflächenbearbeitungseinheit gemäß Fig. 1 aus einer weiteren Perspektive;

Fig. 3a

eine Seitenansicht der Umfangsflächenbearbeitungseinheit gemäß Fig. 1;

Fig. 3b

eine Draufsicht der Umfangsflächenbearbeitungseinheit gemäß Fig. 1 entsprechend einer in Fig. 3a mit IIIb - IIIb bezeichneten Schnittebene;

Fig. 4

eine perspektivische Ansicht einer Ausführungsform einer Werkzeugmaschine mit einer Umfangsflächenbearbeitungseinheit gemäß Fig. 1;

Fig. 5

eine Seitenansicht der Werkzeugmaschine gemäß Fig. 4 bei Kontakt eines Finishbands mit einer bezogen auf eine Werkstückachse auf 3 Uhr positionierten Werkstückumfangsfläche;

Fig. 6

eine der Fig. 5 entsprechende Seitenansicht bei Positionierung der Werkstückumfangsfläche auf 12 Uhr;

Fig. 7

eine perspektivische Ansicht einer Axialflächenbearbeitungseinheit; und

Fig. 8

eine perspektivische Ansicht einer Ausführungsform einer Werkzeugmaschine mit einer Umfangsflächenbearbeitungseinheit gemäß Fig. 1 und mit einer Axialflächenbearbeitungseinheit gemäß Fig. 7.

Further features and advantages of the invention are the subject of the following description and the drawings of preferred embodiments.
In the drawings show:

Fig. 1

a perspective view of an embodiment of a peripheral surface processing unit from a first perspective;

Fig. 2

a perspective view of the peripheral surface processing unit according to Fig. 1 from another perspective;

Fig. 3a

a side view of the peripheral surface processing unit according to Fig. 1 ;

Fig. 3b

a plan view of the peripheral surface processing unit according to Fig. 1 according to one in Fig. 3a Section IIIb - IIIb;

Fig. 4

a perspective view of an embodiment of a machine tool with a peripheral surface processing unit according to Fig. 1 ;

Fig. 5

a side view of the machine tool according to Fig. 4 upon contact of a finishing belt with a workpiece peripheral surface positioned at 3 o'clock relative to a workpiece axis;

Fig. 6

one of the Fig. 5 corresponding side view when positioning the workpiece peripheral surface at 12 o'clock;

Fig. 7

a perspective view of an axial surface processing unit; and

Fig. 8

a perspective view of an embodiment of a machine tool with a peripheral surface processing unit according to Fig. 1 and with an axial surface processing unit according to Fig. 7 ,

An embodiment of a peripheral surface processing unit is in the Figures 1 to 3b represented there and designated as a whole by the reference numeral 10.

The peripheral surface processing unit 10 has a carrier unit 12, which serves for connection to the frame or a positioning device of a machine tool. The carrier unit 12 has a first linear guide part 14 of a linear guide 16, which comprises a second linear guide part 18, which is connected to a first bearing part 20 (see. Fig. 3b ). The linear guide 16 makes it possible to move the first bearing part 20 relative to the support unit 12 along a straight axis 22.

For driving the first bearing unit 20 along the axis 22 and relative to the carrier unit 12, a linear drive 24 in the form of a pneumatic cylinder 26 is provided (see. Fig. 2 ). The linear drive 24 is supported by one end 28 (for example the rear end of a cylinder) on a support 30 of the carrier unit 12. The opposite end 32 of the linear drive 24 (for example, the free end of a piston) is connected to a coupling element 34 which is fixedly connected to the second linear guide part 18 of the linear guide 16 and to the first bearing part 20.

The first bearing part 20 comprises a pivot bearing 36 (see. Fig. 3b ). This means that the pivot bearing 36 is displaced along the rectilinear path 22 when the first bearing part 20 is displaced relative to the support unit 12. The pivot bearing 36 defines a pivot axis 38.

The pivot bearing 36 serves for the pivotal mounting of a generally designated by the reference numeral 40 second bearing part. The second bearing part 40 has rolling bearings 42 which are accommodated in a bearing housing 44 which is connected to a base plate 46 of the second bearing part 40.

The base plate 46 also serves to mount an oscillating drive 48 described in more detail below (cf. Fig. 1 ). The oscillation drive 48 has a drive housing 50 for receiving a motor 52 (see. Fig. 1 and 3b ). The motor 52 acts via a drive shaft 54 on an eccentric unit 56 which cooperates with a carriage 58.

The carriage 58 serves for fastening a finishing tool holder 60 (cf. Fig. 3b and Fig. 2 ). When the oscillation drive 48 is active, the carriage 58 and the finish tool holder 60 are reciprocated along an oscillation axis 62; the bearing parts 20 and 40 and the carrier unit 12 are driven by the oscillating drive 48 is not oscillating. The oscillation axis 62 extends in particular perpendicular to the rectilinear path 22 along which the first bearing part 20 is movable relative to the carrier unit 12.

The finishing tool holder 60 serves for fastening a finishing tool, for example in the form of a finishing stone, not shown. Preferably, the finish tool holder 60 cooperates with a finishing tool 64 in the form of a finishing tape 66 (see FIG. Fig. 3a ). For this purpose, the finishing tool holder may have a prism-shaped receiving region 68 (cf. Fig. 2 ). A section of the finishing strip 66 can proceed starting from a state stretched across the receiving region 68 (cf. Fig. 3a ) deform into the receiving area 68, so that this section is also arranged in the receiving area 68 when processing a workpiece circumferential surface 72 of a workpiece 70 and cooperates there with the finishing belt 66 (cf. Fig. 1 ). The first bearing part 20 and the second bearing part 40 together form a bearing unit 74 (cf. Fig. 3b ). In order to avoid an uncontrolled, gravitational tilting of the second bearing part 40 relative to the first bearing part 20, retaining arms 76 are provided on the second bearing part 40, which protrude in opposite directions from the coupling element 34 and each serve for fastening ends of springs 78, wherein the springs 78 are connected at their opposite ends to a receptacle 80 of the second bearing part 40.

If the second bearing part 40, starting from the in Fig. 2 shown basic position is pivoted about the pivot axis 38 upwards, the lower spring 78 lasts, so that it exerts an increasingly higher tensile force on the second bearing part 40. In a pivoting of the second bearing part 40, starting from the in Fig. 2 illustrated basic position down the upper spring 78 lasts so that it exerts an increasingly higher tensile force on the second bearing member 40. Together define the two springs 78, a basic position of the second bearing part 40 about the pivot axis 38. At the same time provide the two springs 78 mass balance forces that counteract the inertia forces of the reciprocating second bearing part 40.

The bearing unit 74, preferably the second bearing part 40 of the bearing unit 74, in a preferred embodiment also serves to stock a finishing tool 64 in the form of a finishing belt 66. For this purpose, a storage device 82 is provided, which is preferably designed in the form of a supply roll 84 which is rotatably mounted on the base plate 46 of the second bearing part 40 (see. Fig. 1 ). The supply roll 84 serves for the storage of fresh, unused finishing strip 66. The used finishing strip 66 is fed to a collecting device 86, which is preferably designed as a collecting roll 88.

The storage device 82 and the collector device 86 are preferably arranged on an end of the second bearing part 40 facing away from the finish tool holder 60.

Preferably, a finishing belt drive 90 is also provided which serves to supply fresh finish belt to the finish tool holder 60 and the workpiece 70. The finishing belt drive 90 includes, for example, a motor 92 (see. Fig. 3b ), via a transmission (drive shaft 94, drive belt 96, drive wheel 98, see also Fig. 3a ) cooperates with the collecting roller 88 of the collecting device 86.

In order to supply the finishing tool holder 60 and the workpiece 70 fresh finishing belt 66, the motor 92 is actuated so that from the collection side a spent finishing belt section is pulled out of the area of the finish tool holder 60 and fresh finishing belt is withdrawn from the supply roller 84 of the storage device 82.

An additional portion of the finishing tape 66 may be stored by means of a memory device 99 (cf. Fig. 2 ) are stored and released. The storage device 99 is likewise arranged on the second storage part 40 and preferably downstream of the storage device 82.

The storage device 99 comprises a setting roller 99a, which is arranged between two counter-rollers 99b when viewed in the direction of the finishing belt 66. The adjusting roller 99a is arranged on a lever 99c, the position of which can be changed by means of an adjusting cylinder 99d. Depending on the position of the lever 99c, a shorter or a longer section of finishing belt 66 is intermediately stored between the two counter-rollers 99b.

In the Fig. 1 and 2 a state is shown in which a shorter portion of finishing belt 66 is temporarily stored (actuating cylinder 99d retracted); this corresponds to the fact that upon contact of the finishing strip 66 with the workpiece surface 72, the course of the finishing strip 66 follows the geometry of the prism-shaped receiving region 68 and takes up more length there. In Fig. 3a a state is shown in which a longer portion of finishing belt 66 is temporarily stored (actuating cylinder 99d extended); this corresponds to the fact that the finishing belt 66 is just stretched over the receiving area 68 and takes up less length there.)

In the FIGS. 4 to 6 a machine tool is shown, which is generally designated by the reference numeral 100 and the one, with reference to above Figures 1 to 3b described circumferential surface processing unit 10 includes.

The machine tool 100 has a frame 102 with which the machine tool 100 can be set up on a footprint 104. The frame 102 has a mounting surface 106, which may be formed by at least one or more fasteners 108.

On the mounting surface 106, a workpiece holder 110 is attached. The workpiece holder 110 includes, for example, a headstock 112 and a (not shown) tailstock. The headstock 112 has a rotary drive 114, which serves to rotate a workpiece 70, for example in the form of a crankshaft, about a central workpiece axis 116.

Upon rotation of the workpiece 70 about the workpiece axis 116, the workpiece peripheral surface 72 eccentric with respect to the workpiece axis 116 moves along a path of movement 118 which enters into the workpiece axis FIGS. 5 and 6 dotted is shown.

The workpiece 70 may also have to the workpiece axis 116 concentric workpiece peripheral surfaces 120, which for example each form a main bearing of a crankshaft.
The machine tool 100 comprises a positioning device 122 described below, which serves to be able to position the peripheral surface processing unit 10 along a positioning axis 124. The Positioning axis 124 is parallel to the workpiece axis 116. The positioning device 122 includes a positioning drive 125, which via a drive belt (in Fig. 4 covered by a belt box 126) acts on a spindle which extends along the positioning axis 124. The spindle cooperates in a conventional manner with a spindle nut which is connected to a positioning slide 128. The positioning carriage 128 has a mounting surface 130, which serves to fasten the carrier unit 12 of the peripheral surface processing unit 10.

It is possible that a second positioning device 122 'is provided, with a second drive 125', with a second belt (in Fig. 4 concealed by a second strap chest 126 '), with a second positioning slide 128', which has a second positioning slide 128 '
Attachment surface 130 'has. The second positioning device 122 'serves to be able to move the second positioning carriage 128' along a second positioning axis 124 '. The second positioning axis 124 'preferably runs parallel to the workpiece axis 116. The second positioning carriage 128' may be used to arrange an additional peripheral surface processing unit 10 or to arrange one below and with reference to FIG Fig. 7 described axial surface processing unit 150th

For finish machining a workpiece peripheral surface 72, the workpiece 70 is clamped in the workpiece holder 110, ie between the headstock 112 and the tailstock, not shown.

The peripheral surface processing unit 10 can be positioned along the positioning axis 124 by means of the positioning device 122, so that the finishing belt 66 is arranged along the workpiece 70 at the level of a workpiece peripheral surface 72 to be finished.

Starting from a state in which the finishing belt 66 is spaced from the workpiece peripheral surface 72 (see FIG. Fig. 4 , Storage device 99 stores longer additional portion of finishing tape 66), the finishing tape can be delivered towards the workpiece peripheral surface 72. For this purpose, the linear drive 24 is driven so that the first bearing part 20 and thus the entire bearing unit 74 and thus also the finishing tool holder 60 and the finishing belt 66 are displaced in the direction of the workpiece axis 116. As a result, the finishing belt 66 engages with the workpiece peripheral surface 72, cf. Fig. 5 (Storage device 99 releases cached additional section). The linear drive 24, in particular the pneumatic cylinder 26, is controlled so that the finish tool holder 60 presses not only weakly, but with a predetermined pressing force with the finishing belt 66 against the workpiece peripheral surface 72.

For finishing machining of the workpiece circumferential surface 72, the workpiece 70 is driven by the rotary drive 114 in the direction of rotation about the workpiece axis 116. As a result, the workpiece circumferential surface 72 moves along the movement path 118 (cf. FIGS. 5 and 6 ). During the movement of the workpiece peripheral surface 72 along the movement path 118, the finishing belt 66 is permanently in contact with the workpiece peripheral surface 72. The required for following the movement path 118 compensating movement is generated on the one hand that the second bearing member 40 to the pivot axis 38 pivots relative to the first bearing part 20 back and forth. On the other hand, the compensation movement is provided by the fact that the entire storage unit 74 is reciprocated relative to the carrier unit 12 along the rectilinear path 22. In this case, a piston and a cylinder of the linear drive 24 move relative to each other. In this way, the workpiece peripheral surface 72 eccentric to the workpiece axis 116 can be finish-machined.

In a particularly preferred method for machining a workpiece 70, the same peripheral surface processing unit 10 with which a workpiece peripheral surface 72 eccentric to a workpiece axis 116 is machined is also used to finish machining a workpiece peripheral surface 120 concentric with the workpiece axis 116. Since the workpiece peripheral surface 120 does not move along a trajectory about the workpiece axis 116, but only rotates concentrically to the workpiece axis 116, no finishing movement takes place during the finishing machining of a workpiece peripheral surface 120. This means that the second bearing part 40 is stationary relative to the first bearing part 20 and is not pivoted about the pivot axis 38 back and forth. Further, the entire storage unit 74 stands still and does not move along the rectilinear path 22 relative to the carrier unit 12.

Regardless of whether the peripheral surface machining unit 10 is used to machine an eccentric workpiece peripheral surface 72 or a concentric workpiece peripheral surface 120, the oscillation movement of the finish tool holder 60 and thus of the finishing belt 66 is generated by means of the oscillation drive 48. It is advantageous that the reciprocating masses are small and limited to the carriage 58 and the finishing tool holder 60 and to portions of the finishing belt 66.

Whether or not an eccentric workpiece peripheral surface 72 or a concentric workpiece peripheral surface 120 is to be machined, it is possible for the oscillator driver 48 to be inactive. Thus, for example, the sealing seat of a crankshaft can be processed, which should not be provided with a cross-cut structure. This cross-cut structure is characteristic of finish machining of a workpiece peripheral surface, but undesirable for a sealing seat (because the cross-cut structure would form an undesirable oil transport surface between the interior and the periphery of a crankcase).

In the event that a workpiece peripheral surface finish, so with cross-cut structure to be processed, it is possible that the oscillation movement, which is generated by the oscillating drive 48, a further movement is superimposed in the form of a Überlagungshubs. This is particularly advantageous if the width of the finishing strip 66 is smaller than the width of a workpiece surface to be machined finish finish 72 or 120. The Überlagerungshub can be realized in a simple manner by means of the positioning 122, the positioning slide 128 along the positioning axis 124 back and reciprocated. Here, the frequency at which the positioning carriage 128 is reciprocated is lower than the oscillation frequency of the carriage 58 and the finishing tool holder 60. The amplitude of the additional movement of the positioning carriage 128 is so large that a narrower finishing belt 66 can process the entire width of a workpiece end surface 72, 120 to be finished with a finish.

In Fig. 7 is an overall designated by the reference numeral 150 Axialflächenbearbeitungseinheit shown. This is used for finishing machining surfaces of a surface pair, which are perpendicular to a workpiece axis 116. Such a surface pair can also be referred to as a "passport bearing".

The axial surface processing unit 150 may alternatively to a peripheral surface processing unit 10, but preferably in addition to a peripheral surface processing unit 10 on a machine tool 100 (see. Fig. 8 ) be provided.

The axial surface processing unit 150 serves to bring different finishing tapes 66a, 66b into contact with respectively different surfaces of a surface pair of a workpiece 70. For this purpose, the axial surface processing unit 150 has two pressing tools 152, 154, each with associated pressing surfaces 156, 158. The pressing tools 152, 154 are held on a holder 160.

In Fig. 7 For example, the pressing tools 152, 154 are shown in a state in which the pressing surfaces 156, 158 facing in opposite directions have the smallest possible distance relative to each other. The pressing tools 152, 154 can continue by means of a wedge element 162, which cooperates with a wedge guide 164 of the pressing tools 152, 154 be pressed apart, so that the distance of the pressing surfaces 156, 158 increases. To drive the wedge member 162, a pneumatic cylinder 166 is provided. The pressure of the pneumatic cylinder 166 also controls the force with which the pressing surfaces 156, 158 abut against surfaces of a pair of surfaces to be finished.

The axial surface processing unit 150 has a carrier unit 168, which for connection to the positioning slide 128 'of the second positioning device 122' (see FIG. Fig. 4 ) serves.

An oscillation drive 170 is attached to the carrier unit 168. This acts via an eccentric with a carriage 172 together, which is mounted relative to the carrier unit 168 by means of a linear guide 174 along an axis of oscillation 176 slidably. The oscillation axis 176 is perpendicular and spaced from a workpiece axis 116 of a workpiece 70 to be finished.

It is possible that the tool holder 160 is directly connected to the carriage 172. In a preferred embodiment, however, an additional linear guide 178 is provided between the tool holder 160 and the carriage 172, which provides an additional degree of freedom for the tool holder 160 along a movement axis 180. The movement axis 180 preferably runs parallel to the workpiece axis 116. The additional linear guide 178 makes it possible to work surfaces perpendicular to a workpiece axis of a surface pair of a workpiece 70 which is driven to oscillate in a direction parallel to the workpiece axis 116 (this is the case with the machine tools 100 described here not the case, but in conventional machine tools, in which a workpiece for finishing machining is driven oscillating together with a workpiece holder and with a rotary drive in a direction parallel to a workpiece axis direction). In addition, the additional linear guide 178 makes it possible to compensate for length tolerances of a workpiece 70. In addition, it is possible to work on wider seats, with only one surface of a surface pair being edited.

Subsequently, tape guide elements for the different finishing tapes 66a, 66b are described, which are each provided for each of the two finishing tapes 66a, 66b.

Starting from separate storage units 182, 184 for the different finishing belts 66a, 66b, deflection rollers 186, 188 cause a rotation of a respective finishing belt 66a, 66b by 90 °. This is followed in each case by a first band clamping device 190.

Via a strip turning device 192, the finishing strip 66a, 66b respectively reaches the pressing surfaces 156, 158, which respectively interact with a rear side of a finishing strip 66a, 66b (ie with the non-abrasive surfaces of a finishing strip 66a, 66b), respectively on the front side of the Press finishing belt disposed abrasive surface against each one of the finishend to be machined surfaces of a pair of surfaces.

Starting from the pressing surfaces 156, 158, the finishing belt 66a, 66b respectively reaches a second belt clamping device 194 and is finally rotated back by 90 °, in each case by means of deflection rollers 196, 198 and finally to a collecting device 200 (not shown). The collecting device 200 may be a collecting roller or, in the simplest case, a collecting trough.

When arranging an axial surface processing unit 150 on a machine tool 100, it is possible to arrange further support elements 202 on the frame 102 or its attachment surface 106, for example retaining rails which serve for the preferably displaceable arrangement of separate storage units 182, 184 for respective finishing belt 66a, 66b.

It is understood that the machining of axial surfaces of a fiducial bearing of a workpiece 70 by means of the axial surface processing unit 150 can take place simultaneously with the finishing machining of workpiece peripheral surfaces 72 or 120 (cf. Fig. 8 ). Even when machining axial surfaces, the workpiece 70 is rotated about the workpiece axis 116. This rotational movement is superposed by means of the oscillation drive 170 an oscillatory movement of the finishing tapes 66a, 66b along the axis of oscillation 176.

In Fig. 8 further parts of a workpiece holder 110 are shown; In addition to the headstock 112 with rotary drive 114, these are a drive 220 for a carriage 222, which is movable parallel to the workpiece axis 116. The carriage 222 is preferably used for attachment of a tailstock of the workpiece holder 110, not shown.

Claims (15)

A peripheral surface processing unit (10) for finishing machining workpiece peripheral surfaces (72) eccentric to a workpiece axis (116) by at least one finishing tool (64), said at least one finishing tool (64) being retained on a finishing tool holder (60) and said finishing tool holder (60). is movable along a movement path (118) of the workpiece peripheral surface (72) during machining of a workpiece peripheral surface (72), characterized in that the peripheral surface processing unit (10) comprises an oscillation drive (48) by means of which the finishing tool holder (60 ) can be driven to oscillate in a direction parallel to the workpiece axis (116). Circumferential surface processing unit (10) according to claim 1, characterized in that the oscillation drive (48) between the bearing unit (74) and the finishing tool holder (60) is effective. Peripheral surface processing unit (10) according to one of the preceding claims, characterized in that the oscillation drive (48) comprises an eccentric unit (56). Peripheral surface processing unit (10) according to any one of the preceding claims, characterized in that the peripheral surface processing unit (10) comprises a support unit (12) on which a first bearing part (20) of the bearing unit (74) displaceable is mounted, wherein the first bearing part (20) has a jointly with this slidable pivot bearing (36), wherein on the pivot bearing (36) relative to the first bearing part (20) pivotable second bearing part (40) of the bearing unit (74) is mounted , wherein on the second bearing part (40) of the oscillation drive (48) and the finishing tool holder (60) are arranged. Peripheral surface processing unit (10) according to claim 4, characterized in that on the carrier unit (12) a linear drive (24) is arranged, by means of which the first bearing part (20) along a rectilinear path (22) is displaceable. Peripheral surface processing unit (10) according to claim 5, characterized in that the linear drive (24) as pressing means for setting a pressing force is effective, with which the at least one finishing tool (64) presses against a finishend to be machined workpiece peripheral surface (72). Peripheral surface processing unit (10) according to one of the preceding claims, characterized in that the finishing tool (64) is designed as a finishing belt (66) and that a) on the storage unit (74) a storage device (82) for fresh finishing tape and / or a collecting device (86) for collecting spent finishing tape is or are arranged and / or b) the peripheral surface processing unit (10) has a finishing belt drive (90), which as Train drive is formed and by pulling on a spent finishing tape section the finishing tool holder (60) supplies a fresh finishing belt section
and or c) the peripheral surface processing unit (10) has an finish tape storage device (99) which stores an additional portion of the finishing belt (66) when the finishing belt (66) is not in contact with a workpiece (70) and releases the auxiliary portion of the finishing belt (66) when the finishing belt (66) comes into contact with the workpiece (70). Peripheral surface processing unit (10) according to one of the preceding claims, characterized in that the finishing tool holder (60) and the finishing tool (64) are formed such that they allow the machining of workpiece peripheral surfaces (72, 120) with different diameters. Use of the circumferential surface processing unit (10) according to any one of the preceding claims for finishing machining a workpiece circumferential surface (120) of a workpiece (70) concentric with a workpiece axis (116). Machine tool (100) with a peripheral surface processing unit (10) according to one of claims 1 to 8 and with a workpiece holder (110) for holding a workpiece (70) comprising at least one first positioning device (120) for positioning the peripheral surface processing unit (10), in particular one Carrier unit (12) of Peripheral surface processing unit (10), relative to the workpiece holder (110). Machine tool (100) according to claim 10, characterized in that the workpiece holder (110) comprises a rotary drive (114) for driving the workpiece (70) about the workpiece axis (116), wherein preferably the workpiece (70) in one to the workpiece axis ( 116) parallel direction immovably in the workpiece holder (110) is held. Machine tool (100) according to claim 10 or 11, comprising at least one second positioning means (122 ') for positioning an axial surface processing unit (150) for finishing machining perpendicular to a workpiece axis (116) surfaces of a surface pair of a workpiece (70), preferably the Axialflächenbearbeitungseinheit (150) has two separate finishing tapes (66a, 66b), each serving for processing only one surface of the two surfaces of the surface pair. A method of operating a peripheral surface processing unit (10) according to any one of claims 1 to 8 or a machine tool (100) according to any one of claims 10 to 12, characterized in that a force with which the at least one finishing tool (64) against a finish to be machined Workpiece peripheral surface (72) is adjusted by adjusting the position of the at least one finishing tool (64) along a rectilinear path (22), and / or that the peripheral surface processing unit (10) during finishing machining a workpiece peripheral surface (72) and the oscillating movement of the at least one finishing tool (64) is superimposed reciprocated in the direction parallel to the workpiece axis (116). A method of operating a peripheral surface processing unit (10) according to any one of claims 1 to 8 or a machine tool (100) according to any one of claims 10 to 12, characterized in that in the same clamping of a workpiece (70) using the same peripheral surface processing unit (10) successively different Workpiece peripheral surfaces (72, 120) of the same workpiece (70) machined finishend. A method according to claim 14, characterized in that the workpiece (70) is a crank or compressor shaft and the different workpiece peripheral surfaces (72, 120) comprise main bearings, connecting rod bearings and / or sealing seats or that the workpiece (70) is a camshaft and the different Workpiece peripheral surfaces (72, 120) comprise shaft bearings and cam surfaces.

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