EP1330338B1 - Multi-purpose machine - Google Patents

Abstract

The invention concerns a method and an apparatus in which crankshafts and similar components can be machined at the relevant machining locations (big-end bearing locations, main bearing locations, side cheek side surfaces, end journal/end flange) on one machine and thus with a low level of expenditure in terms of investment items and nonetheless overall in highly time-efficient manner, by mechanical material removal in one and the same machine, wherein in all machining steps the workpiece is gripped on the central axis and is drivable in rotation and the concentric rotationally symmetrical surfaces are machined by workpiece-based methods.

Description

I. Field of application

The invention relates to the machining of workpieces by means of material-removing, preferably mechanically material-removing process and related Devices, the workpieces being both centric and eccentric arranged rotationally symmetrical with respect to the central axis of the workpiece Surfaces and possibly further front surfaces includes the are to be processed (see e.g. WO-A-95 05265 or EP-A-0 807 489).

II. Technical background

A typical workpiece of this type is crankshafts, in which the lateral surfaces the main bearing represents the centric, rotationally symmetrical surfaces and the lateral surfaces of the pin bearings the eccentric rotationally symmetrical Surfaces. In addition, the machining operations are centric, however the end area and thus the area used for tensioning in chucks End pegs or end flanges (small or large outer diameter) a difficulty, and the associated with the decrease in large quantities of material Machining cheek side surfaces.

Crankshafts are typical representatives of workpieces that have the following problems to unite:

• es sind zusätzlich Stimflächen zu bearbeiten,
• es müssen auch die Endbereiche des Werkstückes, an denen normalerweise die Spannung in den Futtern der Maschine erfolgt, bearbeitet werden, und diese müssen in hohem Maße hinsichtlich Rundheit und Mittenfluchtung mit den übrigen Bereichen des Werkstückes übereinstimmen,
• das Werkstück ist aufgrund seiner Geometrie wenig widerstandsfähig gegen vor allem radial aufgebrachte Bearbeitungskräfte.

Both centrically and eccentrically positioned, rotationally symmetrical workpiece surfaces must be machined,

• additional end faces must be machined,
• the end areas of the workpiece, on which the clamping in the machine chucks normally takes place, must also be machined, and these must correspond to a large extent in terms of roundness and center alignment with the other areas of the workpiece,
• Due to its geometry, the workpiece is not very resistant to radial machining forces.

• werkstückbasierte Verfahren, also Verfahren, bei denen die gewünschte Schnittgeschwindigkeit (Relativgeschwindigkeit zwischen Werkstückoberfläche und der daran arbeitenden Schneide des Werkzeuges) primär durch die Rotationsgeschwindigkeit des Werkstückes erreicht wird: Längsdrehen, Plandrehen, Räumen, Dreh-Räumen (die Räumschneiden sind auf dem Umfang eines runden Werkzeuggrundkörpers angeordnet, welches sich bei der Bearbeitung dreht, jedoch langsamer als das Werkstück), Dreh-Dreh-Räumen (in Ergänzung zum vorbeschriebenen Drehräumen befinden sich auf dem Werkzeuggrundkörper auch Drehwerkzeuge, bei deren Einsatz das Drehräumwerkzeug nicht rotiert, sondern linear in X- oder Z-Richtung bezüglich des Werkstückes zum Längs- bzw. Plandrehen verfahren wird), Finishen (Schleifen mit im wesentlichen stillstehendem Finish-Werkzeug; noch feinere Körnung als Schleifwerkzeuge) und
• werkzeug-basierte Verfahren, bei denen also die Schnittgeschwindigkeit primär durch die Bewegung, insbesondere Rotation, des Werkzeuges erzielt wird: Orthogonalfräsen (ein Fräswerkzeug, das mit seiner Rotationsachse lotrecht auf der zu bearbeitenden rotationssymmetrischen Fläche steht, bearbeitet diese primär mit den auf der Stirnfläche des Fräsers vorhandenen Stirnschneiden), Außenfräsen (ein scheibenförmiger Fräser, dessen Rotationsachse parallel zur Rotationsachse des Werkstückes liegt, arbeitet primär mit den auf seinem Außenumfang angeordneten Schneiden die entsprechende Mantelfläche des Werkstückes), Außenrundschleifen (anstelle des vorbeschriebenen scheibenförmigen Fräswerkzeuges wird in gleicher Positionierung zum Werkstück eine scheibenförmige Schleifscheibe eingesetzt).

The well-known range of material-removing machining processes is available for machining the individual surfaces, starting with the machining processes whose tools have a geometrically defined cutting edge. These processes can be divided into the following two groups:

• Workpiece-based processes, i.e. processes in which the desired cutting speed (relative speed between the workpiece surface and the cutting edge of the tool working on it) is primarily achieved by the speed of rotation of the workpiece: longitudinal turning, facing turning, broaching, turning broaching (the broaching blades are on the circumference of a round one Tool base body arranged, which rotates during machining, but slower than the workpiece), turning-broaching (in addition to the above-described turning broaching, there are also turning tools on the tool base body, when using the turning broaching tool does not rotate, but linearly in X or Z direction with respect to the workpiece for longitudinal or face turning), finishing (grinding with essentially stationary finishing tool; even finer grit than grinding tools) and
• Tool-based processes, in which the cutting speed is primarily achieved by the movement, in particular rotation, of the tool: Orthogonal milling (a milling tool that is perpendicular to the rotationally symmetrical surface with its axis of rotation, processes it primarily with that on the end face of the End mill), external milling (a disc-shaped milling cutter, whose axis of rotation is parallel to the axis of rotation of the workpiece, works primarily with the corresponding outer surface of the workpiece with the cutting edges arranged on its outer circumference), external cylindrical grinding (instead of the disk-shaped milling tool described above, one is positioned in the same position as the workpiece disc-shaped grinding wheel used).

The latter representatives in both groups are already procedures with geometrically undefined cutting edge.

There are also processes that remove material without a mechanical one Cutting, for example electroerosion processes, material removal by means of Lasers etc., where, however, only low relative speeds between Tool and workpiece are necessary, and this relative speed either by moving the workpiece and / or the tool Can be made available.

For the large-scale production of workpieces such as car crankshafts are the shortest possible processing time - including set-up and dead times - per crankshaft on the one hand and low tool and energy costs on the other hand, the decisive parameters, depending on the achievable Surface qualities (roundness, roughness depth, etc.) that the need for subsequent Finishing steps such as grinding and / or finishing may require.

In this sense, the means for mass production are still at the moment to prefer mechanical cutting machining processes.

It currently stands with respect to the centric, rotationally symmetrical surfaces processing by means of turning rooms or turning-turning rooms in the foreground. Regarding the eccentric rotationally symmetrical surfaces, for example the hub bearings, external rutide milling is currently preferred. Because the hub storage during processing - all circumferential points from one side can be machined from - rotated around the central axis of the workpiece, is at the same time a chronologically and geometrically very accurate tracking of the corresponding Tools necessary. To be able to realize this, for the machining of these eccentric rotationally symmetrical surfaces is tool-based Process preferred. When using workpiece-based processes - to achieve a high cutting speed and thus efficient processing - Rotate the workpiece so quickly that the tool is tracked would not be feasible, or the speeds that can be achieved in this way of the workpiece and thus cutting speeds would not be competitive.

The currently preferred methods are usually used in large series production used one after the other on separate machines. In addition, usually also on a separate machine or station on a production line - before the end areas, in the case of a crankshaft, i.e. end journal and end flange, separately pre-machined at least on the circumference, possibly also on the end face, to defined clamping surfaces for further processing to have.

For the purposes of the present application, the lateral surfaces to be machined only spoken of rotationally symmetrical surfaces, since this is the is by far the largest proportion of processing cases. Of course you can too not circularly symmetrical, but convexly curved outer surfaces like For example, the cams of camshafts can be processed analogously.

Occasionally, thought has already been given to small quantities, such as pre-series models of crankshafts etc. the processing of the centric rotationally symmetrical Areas through workpiece-based machining processes as well the processing of the eccentric rotationally symmetrical surfaces by tool-based Perform machining operations on a machine by there the two corresponding tool units are both present. there set the extremely different speed ranges of the Workpiece drive is the main problem, and the machining of the end areas the crankshaft the other main problem.

II. Presentation of the invention a) Technical task

It is therefore the object according to the present invention, a method as well to create a device in which crankshafts and similar parts on the relevant Processing points (hub bearings, main bearings, cheek side surfaces, End spigot / end flange) on one machine and thus with a small amount Capital goods expenditure and yet processed overall very efficiently can be.

b) solving the problem

This object is solved by the features of claims 1 and 7. advantageous Embodiments result from the subclaims.

The workpiece should be centered on all machining steps Axis tensioned and driven around this axis to the Avoid using mechanically very complex and expensive so-called cycle chucks, which also severely restrict the flexibility of a machine because they must be geared to the dimensions of the crankshaft to be machined.

By using workpiece-based processes for the central surfaces there already a very short processing time with very good surface quality reached.

By using the tool-based machining processes for eccentric Surfaces, the speed of the workpiece can be kept so low that optimal tool tracking and thus optimum dimensional accuracy of these areas is ensured.

In order for the workpiece-based processes on the one hand and tool-based On the other hand, process the realizable, maximum cutting speeds to be able to reach the workpiece, which in its end areas in Spindles are mounted and can be rotated by means of chuck from both sides forth driven via different drives, one drive the highest possible speeds for the workpiece-based machining processes provides that, on the other hand, only require low torques, while the other drive only has the low workpiece speeds required for tool-based machining processes, however with high torque and compliance with the defined rotational position of the workpiece, thus also a possibility of positioning the rotational position of the workpiece this spindle. Accordingly, this slow drive is preferably also with a self-locking, realized by means of z. B. worm / worm gear ratio, fitted. Both drives can be operated by separate motors (preferred) or driven by a common motor, however at least the self-locking slow drive train z. B. between the spindle and can be uncoupled from the self-locking point or between the chuck and the spindle his.

In addition to end journals and end flanges, at least their outer surfaces, To be able to machine, the spindles must be next to a usual chuck, about a three-jaw chuck, also have a centering point, centering point and the jaws of the jaw chuck relative to each other in the axial direction (Z direction) can be moved, for example by using feeds with retractable jaws. In this way it is possible to have one End area rotatably by means of chuck with the respective spindle connect, while the other end area currently being processed is merely is supported by a centering tip.

The end area recorded in the slow spindle can - due to Drive by the fast spindle - can be operated at high speeds and with the workpiece-based machining process also used for the central bearings, z. B. turn-turn rooms can be edited.

Efficiency restrictions are only in the reverse case, ie Machining of the end area recorded in the fast spindle, in the As a rule, the end flange is necessary: This is only necessary when machining through a centering tip held while the workpiece is on the opposite side is rotated by the jaw chuck of the slow spindle.

Due to the slow speed of the workpiece, there are only two realistically Editing options available:

Either machining using one of the workpiece-based methods, because of lower Workpiece speed, however, at a very low cutting speed, with the corresponding Restriction to suitable cutting materials. When turning is this is, for example, high-speed steel (HSS).

Since the other surfaces processed using tool-based processes, for example the center bearings, even when turning with tools machined from hard metal, cutting ceramics and similar high-performance materials such HSS cutters have to be used solely because of this end flange machining additionally provided on the corresponding tool body become.

Cutting from hard metal or cutting ceramics would be low at these speeds of the workpiece are damaged too quickly.

The other option is to use the same as the low workpiece speed tool-based processes, for example using external round milling, this Edit end area. The disadvantage is that compared to workpiece-based Process slightly poorer achievable surface quality. There in usually for all similar workpiece surfaces, for example all centric Bearings, matching minimum requirements regarding the Surface quality is provided by this end flange machining Circumstances may not meet a quality target that applies to all other central storage locations is achievable due to the more suitable processing method.

Since at least one of the end areas (end journal / end flange) a tension using chuck is usually first on the unprocessed Outer circumference of the workpiece is necessary, at least this must be appropriate Have chuck balancing jaws. Likewise, one of the Spindles fix the workpiece in rotational position relative to one of the spindles be present, for example a rotational position stop or straightening jaws in the corresponding Jaw chuck.

Since, as described above, such processes and machines are primarily for production of crankshafts or similar workpieces in small numbers, often serve only in individual pieces, the external round milling cutters are chosen to be relatively narrow, so that they can be used for all crankshafts to be manufactured. Correspondingly, however, is then - after machining a first axial area on a pin bearing using external round milling - an axial movement of the Milling cutter - be it continuous or gradual - necessary until the entire width of the warehouse is processed.

For this purpose, the milling cutter must be able to be moved in the Z direction the tool support have a Z-slide, and the other must the cutting of the milling cutter not only on its outer circumference, but also in outer edge area of the end face to be present with continuous delivery to be able to cut on the end face in the Z direction. Otherwise, is only the axial section machining via grooving and circumferential machining possible.

If only the processing of individual pieces is intended or the Processing time only plays a very subordinate role, can of the above Solution ideas are deviated so that too the eccentric rotationally symmetrical surfaces and despite the drive during processing via the slow spindle drive with a workpiece-based Machining processes such as turning can be processed. How previously regarding the processing of the fast spindle chuck, however, only slowly drivable, described end area increases thereby the processing time for the pin bearings and thus the crankshaft as a whole very strong and additionally need for this low cutting speed suitable cutting materials such as HSS cutting edges are available.

The advantage of such a solution, however, from a machine point of view, is that that the same machining process is used for the lifting and main bearings, albeit at very different cutting speeds, and consequently with the need for different cutting materials. This from different Material existing cutting edges can either be as previously described from two separate tool units, namely z. B. Cutting from ceramic Cutting materials on a basic tool body and HSS cutting edges the other tool body. Both tool systems however, need the same possibilities of movement (in addition to procedures in the X and Z direction either swiveling around the C2 axis or moving in the Y direction) and can therefore be constructed identically and with a identical control, which reduces costs.

Could take a step further - since it is the workpiece-based The procedure is exclusively a processing procedure in which the Tool does not necessarily have to rotate a full 360 ° - cutting from both Types of cutting material simultaneously on the same, for example disc-shaped, Tool base body can be arranged so that only a single total Tool unit on the machine would be necessary.

Among the high and low workpiece speeds or Cutting speeds or torques when driving the workpiece the following ranges of values are to be understood:

High workpiece speeds from 40 rpm to 1,600 rpm, especially from 200 RPM to 800 RPM, low workpiece speeds from 0 RPM to 40 RPM, in particular from 20 rpm to 40 rpm, high torques of the workpiece drive from 600 Nm to 3,000 Nm, in particular from 2,000 Nm to 2,500 Nm, low torques of the workpiece drive from 200 Nm to 600 Nm, in particular from 300 Nm to 550m, cutting speeds from 150 m / s to 700 mls, especially from 180 m / s to 250 m / s.

A detail problem is posed by those that are often necessary for crankshaft bearings Undercuts at the edge of the bearing point, which at middle bearing points by turning are easy to manufacture when machining the pin bearings using a however, tool-based processes cannot be produced. In this case you have to after machining the outer surface of such a pin bearing, the corresponding Undercuts are made by turning. Since this is the hub storage point rotates eccentrically around the central axis of the workpiece Rotary cutting edge are tracked in the circulation of the workpiece, and due the workpiece can only be driven at the low speed. Accordingly, here again, cutting agents are made of suitable cutting materials such as HSS necessary.

c) working examples

Fig. 1a:

eine erfindungsgemäße Maschine in Frontansicht,

Fig. 1b:

eine andere erfindungsgemäße Maschine in Frontansicht,

Fig. 2a:

die Maschine gemäß Fig. 1a in der Seitenansicht von links,

Fig. 2b:

eine andere Bauform der Maschine in Seitenansicht,

Fig. 3a:

den linken Spindelbereich der Maschine gemäß Fig. 1a in vergrößertem Teilschnitt,

Fig. 3b:

den rechten Spindelbereich der Maschine gemäß Fig. 1a in vergrößertem Teilschnitt,

Figuren 4:

Prinzipdarstellungen bei linksseitigem Antrieb des Werkstückes,

Figuren 5:

Prinzipdarstellungen bei rechtsseitigem Antrieb des Werkstückes, und

Fig. 6:

einen Schnitt entlang der Linie VI-VI der Fig. 1.

An embodiment according to the invention is described in more detail below by way of example. Show it

Fig. 1a:

a machine according to the invention in front view,

Fig. 1b:

another machine according to the invention in front view,

Fig. 2a:

1a in side view from the left,

Fig. 2b:

another design of the machine in side view,

Fig. 3a:

the left spindle area of the machine according to FIG. 1a in an enlarged partial section,

3b:

the right spindle area of the machine according to FIG. 1a in an enlarged partial section,

Figures 4:

Principle representations with left-hand drive of the workpiece,

Figures 5:

Schematic diagrams for right-hand drive of the workpiece, and

Fig. 6:

a section along the line VI-VI of Fig. 1st

Fig. 1a shows a machine tool that a workpiece, such as the one shown Crankshaft 1, which both central surfaces 2, z. B. main storage locations, as well as eccentric surfaces 3, for example pin bearings, at the end areas rotatably drivable and processed.

The axial end region of the workpiece is in the holding devices two mutually aligned, aligned spindles 15, 16 added. Both jaw chuck 20 serve as receiving devices or 21 and centering tips 22, 23, which are arranged on each of the spindles 15, 16 are.

The spindles 15, 16 are arranged on the bed 14 of the machine, as well the tool supports 12, 13, each carrying a tool unit, which about an axis parallel to the axis of rotation (Z axis) of the workpiece (C2 axis) can be driven to rotate.

In addition, the tool supports 12, 13 are in the X direction, that is to say transversely to the axial Z direction, defined to be movable on the respective Z slide that can be moved in the Z direction 26, 27. The Z-slides can be moved along the Z-guides 33. The Tool units are usually disk-shaped tool bodies, the tool body 18 of the one tool support 12 on the outside Circumferential area is occupied with cutting edges, which is necessary for a workpiece-based process can be used, for example with rotary cutting or rotary-rotary broaching.

Accordingly, this tool body 18 does not necessarily have to Allow a full 360 ° to be rotated, but it is already pivoting sufficient for smaller angular ranges around the C2 axis. Taking one However, the defined rotational position of the tool base body 18 is necessary. Corresponding is this tool body 18 when machining a central one rotationally symmetrical surface 2, namely a central bearing.

In contrast, the other tool base body 19 is one with cutting edges tool-based process, for example with milling cutting, in its outer Equipped circumferential area, which accordingly preferably over the distributed over the entire circumference of the disk-shaped base body 19, in particular are evenly distributed. The tool body 19 of this tool-based Accordingly, the process must be more than 360 °, in particular be drivable over any number of revolutions.

The Z-guides 33 are so long that both tool body 18, 19 can reach any axial position on the workpiece in the Z direction, in particular also the end regions, namely that in FIG. 1a at the right end of the crankshaft shown end pin 5 and the one at the left end of the crankshaft 1 illustrated end flange 6, which has a larger outer diameter than the end journal 5 has.

Like in particular the enlarged detail of the left recording area 1a shows, the crankshaft is preferred during machining at both ends in the respective jaw chucks 20, 21, ie with the help of radial gripping jaws 20a, 20b, ..., 21a, 21b, ... held and driven in rotation.

Only if the circumferential areas necessary for the application of the clamping jaws as well as the end faces of the crankshaft are machined on the each side released the tension using jaws, and the crankshaft on this side only by means of a centering tip 22, 23 in a corresponding one Center bore of the crankshaft held. At the same time, the jaws are axially withdrawn on this side in the Z direction opposite the centering tip, so that the tool in question at the end face. B. 5a or Circumferential surface of the end flange or end pin can work.

The entire headstock, in which one of the spindles, for. B. the spindle 16 is mounted in the Z direction opposite the bed 14 of the machine defined travel. This enables the machining of workpieces of different lengths, and also facilitates the loading and unloading of the machine with workpieces. Whether in the axial relative movement of the jaws of a jaw chuck the centering point arranged on the same spindle in the Z direction Jaws are movable relative to the jaw chuck, or the centering tip relative to the chuck or to the spindle is not decisive, whereby in in practice the displacement of the centering tip 22, 23 in the Z direction compared to the associated jaw chuck and the associated spindle is preferred, such as exemplarily in Fig. 3a, 3b separately for the left and right side of the machine is shown. It is also irrelevant whether there is tension in the jaw chuck on the same In addition, the tension through the centering tip on the same Side is maintained.

FIG. 1b shows a machine tool that differs from the solution according to FIG. 1a differs in that the tool support 13 with the associated Tool base body 19, which the cutting for the or the tool-based Proceedings are missing.

FIG. 2a shows the machine according to FIG. 1a from the left side in a section along the line IIa-IIa. It can be seen that the spindle 16 carries Headstock over the tub of a tub-shaped bed 14 in the Z direction movably rests. The one that rotatably supports the tool body 19 Tool support 13, which is designed as an X slide, is in turn in the X direction guided on a Z-slide, with the X-direction directed obliquely downwards at an angle of 60 - 80 ° to the horizontal is inclined.

The guide plane of the Z slide 27 opposite the bed 14 is also not horizontal or vertically, but at an angle of about 40 - 50 ° opposite inclined to the horizontal.

Fig. 2b, on the other hand, shows a bed construction with a bed 14 ', which with respect the Z direction is symmetrical, that is, on two opposite sides inclined guide surfaces each carries a Z-slide 26 ', 27', the again in each case in the X1 or X2 direction, which strive apart in a V-shape, movable tool support 12 ', 13' with corresponding Wear tool body 18 ', 19'.

Figures 3a and 3b show the left and right headstock of the machine.

The respective spindle 15 or 16 is in the headstock, not specified rotatably mounted and axially fixed. On the front end of the The jaw chuck 20 or 21 is connected to the spindle and non-rotatably connected to it the jaws 20a, ..., 21a, ...

Both the spindle 15 and 16 and the jaw chuck 20 and 21 are in Center in the Z direction is hollow throughout, and is in this cavity the centering tip 22 or 23 is mounted, which from the jaw chuck 20 or 21st can also be positioned projecting forward.

The centering tip is rotatably mounted in relation to the spindle and jaw chuck Axial position shiftable.

As will be explained with reference to FIGS. 4 and 5, is for processing possibly the Z position of the centering tip 22, 23 can be fixed necessary despite free rotation about the Z axis. In the solutions according to Fig. 3a, 3b this is solved by means of a movable in the Z direction inside the spindle 15, especially with respect to the inside diameter of the spindle 15 a thread screwable centering stop 34 or 35 loosened the connected to the rear end of the centering tip 22, 23 via an undercut and so that the centering tip can both push and pull. there must have a relative rotatability between the centering tip 22, 23 and the centering stop 34, 35 can be given.

In Fig. 3a - as in Figures 1 - is the workpiece, namely the crankshaft 1, with the end flange 6 at the left end, and the end pin 5 at the right end.

The crankshaft 1 is held on the left side by the clamping jaws 20a, 20b, ... of the jaw chuck 20 on the outer circumference of the end flange 6 rest and tension it, the centering tip 22 additionally in the corresponding Centering hole 36 engages. On the right is the crankshaft on the other hand, only by means of those engaging in the centering bore 37 Centering tip 23 held corresponding to the associated Bakken 21a, 21b, ... of the jaw chuck 21 protrudes further.

Here, too, the Z position of the centering tip 23 is analogous to the other centering tip 22 - by means of a centering stop 35 which can be fixed in the axial position fixed by z. B. the thread between the centering stop 34/35 and the surrounding spindle 15, 16 is self-locking.

The two spindle sides also differ fundamentally in terms of mutual drives:

One, for example left, spindle 15 is at high speeds by means of a Motors M drivable, which is mounted on the headstock and for example a belt drive and related pulleys 28, 29, the spindle 15 drives around the Z axis.

The other, e.g. B. right, spindle 16, however, is by means of another, not shown Motors can be driven slowly by rotating a gear pair by the worm wheel 38 is rotatably connected to the spindle 16 during the Motor, not shown, drives the screw 39. This drive train can be uncoupled, for example by disengaging screw 39 and Worm gear 38, or by disengaging a clutch, not shown in this drivetrain.

Figures 4 and 5 show typical clamping situations of the workpiece, for example a crankshaft 1 when processing the different areas of the workpiece.

Since the machine / method according to the invention is not based on the highest possible machining efficiency, but on complete machining of centric, eccentric and end faces is designed on the same machine, z. B. at Crankshafts preferably also machined the end regions of the crankshaft to a preprocessing - except for the introduction of center holes for the centering tips - to be avoided as far as possible. In this case the peripheral surfaces of the end flange 6 and the end pin 5 are preferred, on which the jaws of the jaw chuck should act, first processed and - if necessary and desired - also the respective end face 5a or 6a.

When machining the end areas of a workpiece, the one to be machined End area preferably held exclusively by means of a centering tip the drive from the other end of the workpiece via the spindle there is done to ensure accessibility for the corresponding tool in the end area to enable at all.

Figures 4a-4d show situations in which the crankshaft is at the left end by means of the jaws 20a, 20b, ... of the jaw chuck 20 on the circumference of the left end area, so z. B. the end flange 6, clamped and driven in rotation becomes. In the solution according to FIGS. 3a, 3b, this is the one that can be driven quickly Spindle 15.

The other, right-hand end, the workpiece, must be able to rotate freely be given, as by means of the slow on the right side Rotary drive of the right spindle 16 is a synchronous drive with also high Speed is not possible.

This is achieved by - as shown in Figures 4a - 4d - the right end of the workpiece is held by only the right centering tip 23 in the corresponding right center hole 37 of the workpiece is seated, and the right Centering spindle 23 opposite the right workpiece spindle 16 and the right one Drivetrain is freely rotatable.

The other option is the right, that is, the slow spindle drive facing, end of the crankshaft in the jaw chuck there tension, but to decouple the drive train of the right chuck, for example, by disengaging the worm 39 from the worm wheel 38 of the Drive train, as shown in Fig. 4e.

Due to the tensions according to FIG. 4, the workpiece can be subjected to high Speed are driven and thus all the centric machining surfaces on the workpiece by means of a machining process on the workpiece such as Turning, turning rooms or turning-turning rooms can be edited. This includes also the end pin 5 arranged on the right side and its end face 5a, up to close to the right centering tip 23 in engagement can be edited.

The workpiece must also be in a defined Z position.

According to FIG. 4a, the right centering tip can be used for this purpose the workpiece to the left until the right centering point 23 reaches a centering stop 35 ', for example in the form of that in the figures 3 shown centering stop 35. In this case, the right to force F2 acting on the left, with which the right centering tip 23 is acted upon, be greater than the opposite force F1 with which the left centering tip 22 is applied.

The same applies in the case of FIG. 4d, but there in the area of the left Chuck a workpiece stop 45 'is present through which the workpiece is pressed against this workpiece stop 45 'with the left end face 6a.

If, on the other hand, the force F1 with which the left centering tip 22 is applied is greater than the right-to-left force of the right centering tip 23, 4b, a timely workpiece stop 44 'must be in the region of FIG right spindle 16 to be present. The right centering tip must be used at the same time 23 remain axially fixed in the right centering hole 37 of the workpiece, thus the Z position of the right centering tip 23 can be fixed without the rotatability the centering point.

Fig. 4c differs from the solution according to Fig. 4b in that - at the same Relation of left to right force of the two centering tips - the left one Centering tip, which is subjected to the higher force, against a longitudinal one Centering stop 34 'presses. This must also - as with the solution according to Fig. 4b - happen before the jaws 20a, 20b of the left jaw chuck 20 closed become.

Fig. 5 shows the drive of the crankshaft from the right side, that is the slow driveline. The right end is therefore in FIGS. 5, for example the end pin 5, the crankshaft 1 on the circumference of the jaws 21a, 21b of the right jaw chuck 21, which is from the assigned spindle 16 is driven slowly rotating.

With this type of drive, the eccentric surfaces, lateral surfaces as well like end faces, the workpiece is machined using a tool-based Procedure, the tool must be tracked in the X direction, such as to explain with reference to FIG. 6. The opposite left end of the Workpiece - according to FIGS. 5a and 5b - also between the jaws 20a, 20b, ... of the jaw chuck 20 there because the one on the left side Powertrain is not self-locking and from the right powertrain is driven by spinning empty with the mediation of the workpiece. This in no way leads to undesired torsion of the workpiece, but the left-hand, idle-running drive train connected to the workpiece rather serves the dynamic damping of the workpiece during machining. This is advantageous because the tool-based tools used here Procedures such as milling because of the interrupted cut Apply greater dynamic loads to the workpiece than the tool-based ones Method.

In addition, the left centering tip 22 can engage on the left side Workpiece remain.

Also the recording of the left side of the workpiece only by means of the left-hand centering tip 22 is possible.

To keep the workpiece in a defined Z position here, either (Fig. 5a) the right centering tip 23 against a centering stop on the right 35 'are driven, which then - analogous to Fig. 4a - by means of right centering point force from right to left in the workpiece F2 greater than the counteracting force of the left centering point F1 or the left feed must be.

The other possibility according to FIG. 5b is that from left to right by means of the left centering tip 22 or the left jaw chuck 20 in the Z direction force F1 acting on the crankshaft should be chosen larger than the opposite one Force F2 and the workpiece against a workpiece stop on the right 44 'to press.

According to FIG. 5c, the workpiece can also be left only from the centering tip be held so that the jaws of the chuck are lifted off the workpiece there are.

Fig. 6 shows the machining of a crank bearing H1 of the crankshaft on the Center bearing ML is tensioned and driven in rotation. It can be seen from this that when the crankshaft rotates around the Z direction, the displacement of the one to be machined Pin bearing pin H1 in the X direction must be compensated by appropriate Tracking the machining tool, for example the rotating tool body 18, to the same extent in the analog direction. From this it is also clear that the diameter of the tool body is large must be chosen enough to be at the most distant position eccentric workpiece surface from the axis of rotation C2 of the tool body still to ensure editing.

Fig. 6 also shows the inclusion of the end pin 5 between the jaws 21 a, 21b, 21c of the jaw chuck 21, and the fixation of the rotational position of the crankshaft compared to the jaw chuck by a ram 31 off-center and transverse to the Z direction against one of the other pin journals, e.g. B. H3, presses to this to press against a rotary stop 32, rotary stop 32 and Ram 31 are rotatably connected to the chuck or the spindle.

LIST OF REFERENCE NUMBERS

1

crankshaft

2

centric surface

3

eccentric area

4

Wangen area

5

end journal

5a

end face

6

end flange

6a

end face

7

pin bearings

8th

main bearing

10

Z direction (axial direction)

11

machine

12

Tool Support

13

Tool Support

14

bed

15

spindles

16

spindles

17

engine

18

Basic tool body

19

Basic tool body

20

Jaw chuck

20a, 20b

jaw

21

jaw

22

centering

23

centering

24

longitudinal stop

25

longitudinal stop

26

Z slide

27

Z slide

28

pulley

29

pulley

30

tail

31

tappet

32

Rotational positions stop

33

Z guide

34

Centering stop

35

Centering stop

36

centering

37

centering

38

worm

39

slug

44 '

Workpiece stop

45 '

Workpiece stop

Claims (14)

1. A method of machining both the concentric (2) and also the eccentric, rotationally symmetrical surfaces (3) of workpieces, in particular crankshafts (1), by mechanical material removal in one and the same machine (11),
      wherein

   the workpiece is clamped and drivable in rotation in all machining steps on the central axis,

   the concentric rotationally symmetrical surfaces (2) are machined by workpiece-based methods, and

   when machining the eccentric rotationally symmetrical surfaces (3) the machining operation is effected by tool-based methods,

   characterized in that
      the workpiece is drivable from one end at high speeds of rotation for machining by means of workpiece-based methods and from the other end at low speeds of rotation and maintaining defined rotational positions for machining by means of tool-based methods.
2. A method as set forth in claim 1 characterized in that the eccentric rotationally symmetrical workpiece surfaces (3) are machined by means of workpiece-based methods but at speeds of workpiece rotation which are lower by at least a factor of 10 than when using tool-based methods.
3. A method as set forth in one of the preceding claims characterized in that the end journals of the workpiece are also machined, and especially when machining the end portions the one end portion is machined at a high speed of rotation of the workpiece and by means of a workpiece-based method and the other end portion is machined at a speed of workpiece rotation lower by at least a factor of 10 by means of a drive from the end of the workpiece drivable at a low speed of rotation.
4. A method as set forth in one of the preceding claims characterized in that the one end portion is an end journal and the other end portion is an end flange of an outside diameter substantially larger than the end journal, in particular in the case of a crankshaft (1) as a workpiece, and the workpiece is drivable at a high speed of rotation from the side, in particular the end flange (6), and/or especially the machining of the end portions is effected as early as possible, in particular prior to the other concentric rotationally symmetrical surfaces, and from machining of the end portions the peripheral surface of at least one of the end portions is used for clamping and/or driving purposes, in particular by means of jaw-type chucks.
5. A method as set forth in one of the preceding claims characterized in that the eccentric rotationally symmetrical surfaces (3), in particular the big-end bearings (7) of a crankshaft (1), are machined prior to the concentric rotationally symmetrical surfaces (2) - except the end regions - , in particular the main bearings (8) of a crankshaft (1), and/or especially the high speeds of rotation of the workpiece during the machining operation are speeds of rotation of between 40 rpm and 1600 rpm, in particular between 200 rpm and 800 rpm, and low speeds of rotation of the workpiece are between 0 rpm and 40 rpm, in particular between 20 rpm and 40 rpm.
6. A method as set forth in one of the preceding claims characterized in that the high drive torque for the workpiece during the machining operation is drive torques of between 600 N x m and 3000 N x m, in particular between 2000 N x m and 2500 N x m and the low drive torque for the workpiece is drive torques of between 200 N x m and 600 N x m, in particular 300 N x m and 550 N x m, and/or especially that the cutting speeds are in the range of between 150 m/s and 700 m/s, in particular between 180 m/s and 250 m/s.
7. A machine (11) for machining both the concentric (2) and also the eccentric, rotationally symmetrical surfaces (3) of workpieces, in particular crankshafts (1), by mechanical material removal, comprising

   a bed (14),

   two oppositely directed, rotationally drivable spindles (15, 16) for receiving and driving the ends of the workpiece, in particular a crankshaft (1), about the longitudinal direction (10), the Z-axis, and

   at least one tool support (12, 13) which is definedly displaceable at least in the X-direction,

      characterized in that

   the one spindle (15) is drivable at a high speed of rotation and the other spindle (16) is drivable at a low speed of rotation and is capable of moving to defined rotational positions (C'-axis), and

   at least one of the spindles (15, 16) has a rotational position-directing device for the workpiece.
8. A machine as set forth in claim 7 characterized in that the tool support (12, 13), in addition to displaceability in the X-direction, has either displaceability in the Y-direction or the possibility of pivotal movement about the Z-direction (C2-axis), and/or especially that the rotational drive for the slower spindle (16) is a self-locking rotational drive and in particular has a worm/worm gear pairing.
9. A machine as set forth in one of the preceding apparatus claims characterized in that the machine (2) has tool supports (12, 13) of which one carries a tool for workpiece-based machining methods, in particular a turning tool, a broaching tool, a rotational broaching tool, a turning-rotational broaching tool or a finishing tool, and the other carries at least one tool for a tool-based machining method, in particular an orthogonal milling cutter or an externally toothed milling cutter.
10. A machine as set forth in one of the preceding apparatus claims characterized in that the drives of the spindles (15, 16) are uncoupleable, and/or especially that the spindles (15, 16) are driven from the same motor (17).
11. A machine as set forth in one of the preceding apparatus claims characterized in that the tools are arranged on at least one disk-shaped main tool body (18, 19) at the external periphery and in particular the tools for tool-based methods are arranged distributed over the entire periphery of the main body (18, 19).
12. A machine as set forth in one of the preceding apparatus claims characterized in that the machine is provided with tools of different materials, in particular materials which are intended for high cutting speeds, in particular above 180 m/s on the one hand and low cutting speeds, in particular a maximum of 180 m/s on the other hand, in particular with hard metal or carbide metal or ceramic cutting materials and high-speed steel (HSS), that is to say steel tools, on the other hand, and/or especially that the machine has only a single tool support (12) on which are arranged tools for high cutting speeds and tools for low cutting speeds, which however are all tools for workpiece-based machining methods.
13. A machine as set forth in one of the preceding apparatus claims characterized in that at least one of the spindles, in particular both spindles (15, 16), have on the one hand a chuck for clamping at the external periphery, in particular a jaw chuck (20) and (21) respectively, and on the other hand a centering point (22) and (23) respectively, in particular a centering point which is movable relative to the chuck in the Z-direction, and/or especially that the centering point (22, 23) is free-runningly rotatably supported.
14. A machine as set forth in one of the preceding apparatus claims characterized in that the centering point (22, 23) can be axially fixed in a defined Z-position with respect to the jaw chuck, and/or especially that at least one and in particular both spindles (15, 16) has a longitudinal abutment (24) or (25) respectively either for the Z-position of the centering point (22, 23) with respect to the jaw chuck (20, 21) or with respect to the spindle (15, 16) or a longitudinal abutment for the workpiece with respect to the jaw chuck (20, 21), and/or especially that the axial forces to which the centering points (22, 23) can be subjected are adjustable, in particular in respect of whether the respective axial force is greater or smaller than the axial force acting on the other centering point, for example (23).

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