EP2218545B1 - Device and method for fine processing of a rotation-symmetric workpiece surface - Google Patents

Description

The invention relates to a device for fine or ultra-fine machining of a rotationally symmetrical workpiece surface of a workpiece, with a drive device for driving the workpiece about an axis of rotation, with respect to the axis of rotation two effective in radial directions guide means and at least one effective in a radial direction tool, with a Pressing device for pressing the workpiece against the drive device, wherein the workpiece viewed in the direction of the axis of rotation between the drive device and the pressing device can be arranged.

In the case of fine or ultra-fine machining of a rotationally symmetrical workpiece surface of a workpiece, the problem with a radial clamping is that rotationally symmetrical workpiece surfaces can be damaged by contact with the clamping tool. To prevent this, devices of the type mentioned above are used. In these devices, the workpieces are not clamped radially but axially. Here, a workpiece is seen in the direction of the axis of rotation between a drive means for driving the workpiece about a rotation axis and a pressing device fixed. The positioning of the workpiece in the radial direction takes place with the aid of two guide devices.

A tool which is effective in the radial direction exerts a force on the workpiece to be machined so that, unless further measures are taken, it can move laterally relative to the axis of rotation, ie in the radial direction. In order to prevent this, it is possible, for example, to provide a third guide device, so that the workpiece is held in the radial direction between three guide devices. Another possibility is to provide only two guide means, which are spaced apart in the radial direction different from the axis of rotation. With proper coordination of the different radial distances of the guide means to the rotation axis and the rotational direction of the workpiece, it is then possible with the aid of two guide means to prevent lateral migration of the workpiece. In this case, however, it is disadvantageous that as a result of the offset between the axis of rotation of the drive device and the actual axis of rotation of the workpiece, this moves in the radial direction relative to the drive device and / or the pressure device, so the end faces of the workpiece on corresponding mating surfaces of the drive device and / or rub the pressing device. As a result, end-side workpiece surfaces of the workpiece and / or the mating surfaces of the drive device and / or the pressing device may be damaged. At the same time, so-called stick-slip effects can occur, which can result in that the workpiece can not be machined with the required accuracy and in particular concentricity tolerances can not be maintained.

The DE 10 2004 052 342 A1 discloses two grinding wheels for machining a workpiece which is supported by a plunger. The plunger is disposed on a line of symmetry of the workpiece to cancel forces acting on the workpiece in a tangential direction.

The US 4,306,382 discloses a workpiece which can be machined simultaneously with three grinding wheels arranged in different radial directions and which is pressed against a workpiece support by means of a holding rod.

Proceeding from this, the present invention seeks to provide a device of the type mentioned, which has the simplest possible structure and by means of which a workpiece can be processed gently and with high precision.

This object is achieved according to claim 1 in a device of the type mentioned above in that the pressing device is effective in a pressing plane, which is offset starting from the axis of rotation in the direction of a space in which the guide means are arranged, so that the pressing plane based is positioned eccentrically on the axis of rotation and offset in the direction of the two guide means.

The displacement of the pressing plane is surprisingly sufficient to generate a transverse force which presses the workpiece in the direction of the guide means. This makes it possible to dispense with a third guide device. At the same time, it is not necessary to different distances of the first two guide means to the axis of rotation of the workpiece and to match a rotational direction of the workpiece.

Preferably, the pressing plane extends parallel to the axis of rotation. As a result, the pressing forces can be exerted as normal forces on a workpiece to be machined, which is pressed by the pressing device in the direction of the drive device.

Furthermore, it is preferred if the pressing plane extends between the axis of rotation and the guide devices. As a result, a lateral migration of the workpiece can be prevented particularly reliable.

It is particularly preferred if the guide devices have guide surfaces for bearing against at least one radial contact surface of the workpiece and if the guide surfaces are spaced identically in the radial direction relative to the axis of rotation. This ensures that the actual axis of rotation of the workpiece and the axis of rotation of the drive device are collinear with each other. As a result, a sliding relative movement between the workpiece on the one hand and the drive device and the pressing device on the other hand prevented, so that the workpiece is mounted particularly wear in contact areas to the drive device and the pressing device. In addition, the device can be set up particularly easily before the machining of a workpiece, in particular a series of workpieces, since it is possible to set a distance between the guide surfaces and the axis of rotation with the aid of only one workpiece and / or only one reference part.

It is also advantageous if the guide surfaces are rotatably mounted, so that the guide surfaces when plant roll the plant surface of the workpiece on this. This allows a particularly gentle contact of the guide means with the contact surface of the workpiece.

It is particularly preferred if the guide surfaces are arranged mirror-symmetrically with respect to a plane of symmetry which is spanned by the rotation axis and a direction perpendicular to the pressure plane. As a result, the workpiece is held by the direction of rotation independently and reliably in the radial direction.

It is advantageous if the pressing device has at least one pressing surface for abutment against a front-side contact surface of the workpiece, so that high pressure forces can be exerted in the direction of the drive device.

It is furthermore preferred if the at least one pressing surface is rotatably mounted, so that the pressure surface rolls on the front-side contact surface of the workpiece on this at the plant. As a result, a particularly gentle contact between the pressing device and the workpiece is made possible.

It is particularly preferred if the pressing device has at least two pressing surfaces for abutment against a front-side contact surface of the workpiece. In particular, the frontal contact surface of the workpiece is circular or annular, so that the pressing surfaces lie on relatively spaced circular surface portions or annular surface portions or can be stored on this.

In a preferred embodiment of the invention it is provided that the pressure surfaces relative to a Symmetry plane, which is spanned by the axis of rotation and a direction perpendicular to the pressing plane, are arranged mirror-symmetrically. As a result, the workpiece can be reliably fixed regardless of its direction of rotation.

It is further preferred if the at least one pressing surface is movable in a direction parallel to the axis of rotation in the direction of the drive device and opposite thereto. This makes it possible to further space the pressing surface further from the drive device in order to be able to introduce a workpiece into a workpiece space between the drive device and the pressure device. After introduction of the workpiece, the pressing surface can then be moved in the direction of the workpiece until the pressing surface comes into contact with the workpiece and this is pressed against the drive device. After machining the workpiece, the pressure surface can be lifted off the workpiece again to allow easy removal of the workpiece.

In a preferred embodiment of the invention it is provided that the at least one pressing surface is mounted on a carrier, which is pivotable about an axis perpendicular to the axis of rotation carrier axis. The pivoting of the pressing surface about a carrier axis makes it possible to move the pressing surface along a circular arc so that only a component of the movement of the pressing surface extends in a direction parallel to the axis of rotation in the direction of the pressing plane. This allows a particularly gentle and precise contact of the pressing surface with an end face of the workpiece.

It is further preferred if the carrier is mounted on a linear drive which is movable in a direction parallel to the axis of rotation in the direction of the drive means and for this opposite. This makes it possible to generate the pressure forces to be exerted in the direction of the drive device by means of the linear drive.

Preferably, the device for fine or ultra-fine machining is a finishing device with a finishing tool, in particular a finishing stone.

The invention further relates to a method according to claim 15 for fine or ultra-fine machining of a rotationally symmetrical workpiece surface of a workpiece, with a drive device for driving the workpiece about an axis of rotation, with respect to the axis of rotation two effective in radial directions guide means and at least one effective in a radial direction Tool, with a pressing device for pressing the workpiece against the drive means, wherein the workpiece is arranged in the direction of the axis of rotation between the drive means and the pressing means, wherein the pressing means is positioned in a pressing plane which, starting from the axis of rotation in the direction of a space is, in which the guide means are arranged, so that the pressing plane is positioned eccentrically relative to the axis of rotation and that offset in the direction of the two guide means n.

Advantages and embodiments of the method according to the invention have already been explained above with reference to the advantages and embodiments of the device according to the invention.

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

Figur 1

eine perspektivische Ansicht einer ersten Ausführungsform einer Vorrichtung zur Fein- oder Feinstbearbeitung eines Werkstücks;

Figur 2

eine Vorderansicht der Vorrichtung gemäß Figur 1;

Figur 3

eine Draufsicht der Vorrichtung gemäß Figur 1 längs einer in Figur 2 mit III bezeichneten Schnittlinie;

Figur 4

eine Seitenansicht der Vorrichtung gemäß Figur 1;

Figur 5

eine perspektivische Ansicht einer zweiten Ausführungsform einer Vorrichtung zur Fein- oder Feinstbearbeitung eines Werkstücks;

Figur 6

eine Vorderansicht der Vorrichtung gemäß Figur 5;

Figur 7

eine Draufsicht der Vorrichtung gemäß Figur 5; und

Figur 8

eine Seitenansicht der Vorrichtung gemäß Figur 5.

In the drawings show:

FIG. 1

a perspective view of a first embodiment of a device for fine or ultra-fine machining of a workpiece;

FIG. 2

a front view of the device according to FIG. 1 ;

FIG. 3

a plan view of the device according to FIG. 1 along a in FIG. 2 with III designated cutting line;

FIG. 4

a side view of the device according to FIG. 1 ;

FIG. 5

a perspective view of a second embodiment of a device for fine or ultra-fine machining of a workpiece;

FIG. 6

a front view of the device according to FIG. 5 ;

FIG. 7

a plan view of the device according to FIG. 5 ; and

FIG. 8

a side view of the device according to FIG. 5 ,

A first embodiment of a device for fine or ultra-fine machining is in the FIG. 1 represented and designated there by the reference numeral 10. The device 10 is in particular a device for finish machining a workpiece.

The device 10 comprises a drive unit 12 which is arranged on the base side and which serves to drive a workpiece 14 about an axis of rotation 16. The drive device 12 comprises a workpiece carrier 18, on which the workpiece 14 can be placed with a bottom-side end face.

The workpiece 14 can be driven by frictional engagement with a contact surface of the workpiece carrier 18 about the axis of rotation 16. In order to prevent a deflection of the workpiece 14 radially outward, the device 10 comprises a first guide device 20 and a second guide device 22nd

The guide means 20 and 22 each have a guide roller 24 and 26, which are rotatable about stationary guide roller axles 28 and 30, respectively. The guide roller axles 28 and 30 extend in particular parallel to the axis of rotation 16.

The guide rollers 24 and 26 each have cylindrical guide surfaces 32, 34 which serve to bear against a radial abutment surface 36 of the workpiece 14.

The device 10 further comprises a tool 38, which is designed in particular as a finishing tool, and with which a rotationally symmetrical, radially outwardly facing workpiece surface 40 of the workpiece 14 can be processed. For example, the workpiece 14 is an inner shell of a rolling bearing and the workpiece surface 40 is a bearing surface for a rolling element.

The device 10 further comprises a pressure device, generally designated by 42, which serves to press the workpiece 14 from above in the direction of the drive device 12, in particular against the tool carrier 18.

The pressing device 42 comprises a linear drive 44, which is preferably designed as an electric drive with a servo motor. The linear drive 44 comprises a spindle 46 for driving a carriage 48, which can be stopped along the spindle axis ("NC axis") in different positions. The carriage 48 is held on a carriage carrier 50 and mounted there displaceably.

By movement of the spindle 46 of the linear drive 44, the carriage 48 moves in a direction parallel to the axis of rotation 16 direction.

On the carriage 48 a designated as a total of 52 carrier is pivotally mounted. The carrier 52 in particular comprises two carrier arms 54 and 56. The carrier 52 with its carrier arms 54, 56 is pivotable about a carrier axis 58 which runs at an angle, in particular perpendicular to the axis of rotation 16 and is offset relative thereto ("skew arrangement of the carrier axis 58 and the rotation axis 16 ").

The pressing device 42 comprises at least one, preferably two pressing elements 60, 62, which are formed in particular in the form of pressure rollers.

The pressing elements 60, 62 are preferably rotatable about a pressing element axis 63, which in particular is oriented perpendicular to the axis of rotation 16 and offset to this.

The pressing elements 60 and 62 each have at least one pressing surface 64, 66, which are in particular cylindrical. The first pressing surface 64 and the second pressing surface 66 are spaced apart from one another in such a way that they can be applied to different sections of an end bearing surface 68 of the workpiece 14.

If the pressing elements 60 and 62, as shown in the drawing, distributed along the Andrückelementachse 63, additional Andrückflächen 70, 72, while maintaining the distance between the support arms 54 and 56, the pressing device 42 can also be used for workpieces 14, which end face Contact surfaces 68 of different sizes, in particular with different outer diameters, have.

The pressing surfaces 64 and 66 and / or the pressing surfaces 70 and 72 act in a pressing plane 74, which runs parallel to the axis of rotation 16. Within the pressing plane 74, normal forces act, which press the workpiece 14 in the direction of the workpiece carrier 18. In this case, each of the pressing elements 60, 62 is in contact with different sections of the front-side abutment surfaces 68 of the workpiece 14 along a contact line. These contact lines preferably also run within the pressing plane 74.

Relative to the axis of rotation 16, the pressing plane 74 is offset by an offset 76 in the direction of a space 78, in which the guide means 20 and 22 are arranged. The offset 76 is, for example, a few millimeters, preferably at least about 1 millimeter. It is preferred if the guide devices 20, 22 and the pressing elements 60, 62 are arranged mirror-symmetrically relative to a plane of symmetry 80. The plane of symmetry 80 is spanned by a direction perpendicular to the pressing plane 74 and by the axis of rotation 16.

• In einem Ausgangszustand ist die Andrückeinrichtung 42 so weit von der Antriebseinrichtung 12 beabstandet, dass ein Werkstück 14 auf den Werkstückträger 18 aufgelegt werden kann. Das Werkstück 14 wird dann mit einer bodenseitigen Werkstückfläche derart auf den Werkstückträger 18 aufgelegt, dass die radiale Anlagefläche 36 des Werkstücks 14 in Anlage mit den Führungsflächen 32, 34 der Führungseinrichtungen 20, 22 gelangt. Anschließend wird der Schlitten 48 mit Hilfe des Linearantriebs 44 in zu der Rotationsachse 16 parallelen Richtung in Richtung auf das Werkstück 14 zu bewegt, so dass die Andrückelemente 60 und 62 mit ihren Andrückflächen 64, 66 gegen die stirnseitige Anlagefläche 68 des Werkstücks 14 gedrückt werden.
• Zusätzlich oder alternativ hierzu ist es möglich, den Linearantrieb 44 so anzusteuern, dass die Andrückflächen 64 und 66 der Andrückelemente 60 und 62 zunächst noch von der stirnseitigen Anlagefläche 68 des Werkstücks 14 beabstandet sind und in einem nächsten Schritt die Trägerarme 54 und 56 um einen Winkel 82 um die Trägerachse 58 verschwenkt werden. Diese Schwenkbewegung kann mit Hilfe eines Spannmoduls 84 unterstützt werden. Durch Bewegung der Trägerarme 54, 56 um die Trägerachse 58 bewegen sich die Andrückelemente 60, 62 entlang eines Kreisbogens 86, so dass die Andrückflächen 64 und 66 besonders schonend und präzise an die stirnseitige Anlagefläche 68 des Werkstücks 14 angelegt werden können.

The device 10 works as follows:

• In an initial state, the pressing device 42 is so far away from the drive device 12 that a workpiece 14 can be placed on the workpiece carrier 18. The workpiece 14 is then placed on the workpiece carrier 18 with a bottom-side workpiece surface in such a way that the radial abutment surface 36 of the workpiece 14 comes into abutment with the guide surfaces 32, 34 of the guide devices 20, 22. Subsequently, the carriage 48 is moved by means of the linear drive 44 in the direction parallel to the axis of rotation 16 in the direction of the workpiece 14, so that the pressing elements 60 and 62 are pressed with their Andrückflächen 64, 66 against the end-side abutment surface 68 of the workpiece 14.
• Additionally or alternatively, it is possible to control the linear drive 44 so that the pressing surfaces 64 and 66 of the pressing members 60 and 62 are initially spaced from the end face 68 of the workpiece 14 and in a next step, the support arms 54 and 56 at an angle 82 are pivoted about the support shaft 58. This pivotal movement can be supported by means of a clamping module 84. By moving the support arms 54, 56 about the support shaft 58, the pressing elements 60, 62 move along a circular arc 86, so that the pressing surfaces 64 and 66 are particularly gentle and can be applied precisely to the frontal contact surface 68 of the workpiece 14.

As an alternative to the described pivoting movement, it is possible to provide an additional linear drive which moves the pressing elements 60 and 62 in a direction parallel or inclined to the offset 76, preferably along an NC axis.

The offset 76 between the pressing plane 74 and the axis of rotation 16 in the direction of the guide means 20 and 22 results in rotational drive of the workpiece 14, a force which presses the workpiece 14 against the guide means 20 and 22. As a result, a lateral deflection of the workpiece 14 is excluded, so that the machined rotationally symmetrical workpiece surface 40 of the workpiece 14 by means of the tool 38 can be processed very accurately.

In addition, machining of the workpiece surface 40 with the aid of the tool 38 generates a machining force which presses the workpiece 14 in the direction of the guide devices 20, 22.

One in the FIGS. 5 to 8 illustrated second embodiment of a device 10 for fine or ultra-fine machining of a rotationally symmetrical workpiece surface 40 has a to the above with reference to the FIGS. 1 to 4 described first embodiment of a device 10 of similar construction. Therefore, only the differences from the above-described first embodiment of the device 10 will be discussed below.

The second embodiment of the device 10 has a tool 38, which is positioned within the annular workpiece 14, so that a radially inwardly facing workpiece surface 40 of the workpiece 14 is machinable. For example, the workpiece 14 is an outer shell of a roller bearing and the workpiece surface 40 is a bearing surface for a rolling element.

Incidentally, regarding the construction and operation of the second embodiment of the apparatus 10, reference will be made to the description of the first embodiment of the apparatus 10.

Claims (15)

1. Device (10) for fine or finest processing of a rotationally symmetric work piece surface (40) of a work piece (14), with a drive mechanism (12) for driving the work piece (14) around an axis of rotation (16), with two guidance mechanisms (20, 22) acting in radial directions with respect to the axis of rotation (16) and at least one tool (38) acting in a radial direction, with a pressing mechanism (42) for pressing the work piece (14) against the drive mechanism (12), wherein the work piece (14) can be disposed between the drive mechanism (12) and the pressing mechanism (42) as seen in the direction of the axis of rotation (16), characterized in that the pressing mechanism (42) acts in a pressing plane (74) that is offset from the axis of rotation (16) toward a space (78) in which the guidance mechanisms (20, 22) are disposed, such that the pressing plane (74) is positioned eccentrically relative to the axis of rotation (16) and thus offset toward the two guidance mechanisms (20, 22).
2. Device (10) according to claim 1, characterized in that the pressing plane (74) extends parallel to the axis of rotation (16).
3. Device (10) according to one of the preceding claims, characterized in that the pressing plane (74) extends between the axis of rotation (16) and the guidance mechanisms (20, 22).
4. Device (10) according to one of the preceding claims, characterized in that the guidance mechanisms (20, 22) have guidance surfaces (32, 34) on at least one radial contact surface (36) of the work piece (14) and that the guidance surfaces (32, 34) are at identical distances from the axis of rotation (16) in the radial direction.
5. Device (10) according to claim 4, characterized in that the guidance surfaces (32, 34) are supported such that they can rotate so that, when the guidance surfaces (32, 34) contact the contact surface (36) of the work piece (14) or the work piece holder (18), they roll onto the latter.
6. Device (10) according to claim 4 or 5, characterized in that the guidance surfaces (32, 34) are disposed with mirror symmetry with respect to a plane of symmetry (80) that extends through the axis of rotation (16) and a direction that is perpendicular to the pressing plane (74).
7. Device (10) according to one of the preceding claims, characterized in that the pressing mechanism (42) has at least one pressing surface (64, 66) for contacting a face-end contact surface (68) of the work piece (14).
8. Device (10) according to claim 7, characterized in that the at least one pressing surface (64, 66) is supported such that it can rotate so that, when the pressing surface (64, 66) contacts the face-end contact surface (68) of the work piece (14), it rolls on the latter.
9. Device (10) according to one of the preceding claims, characterized in that the pressing mechanism (42) has at least two pressing surfaces (64, 66) for contacting a face-end contact surface (68) of the work piece (14).
10. Device (10) according to claim 9, characterized in that the pressing surfaces (64, 66) are disposed with mirror symmetry with respect to a plane of symmetry (80) that extends through the axis of rotation (16) and a direction that is perpendicular to the pressing plane (74).
11. Device (10) according to one of claims 7 to 10, characterized in that the at least one pressing surface (64, 66) can be moved towards and away from the drive mechanism (12) in a direction that is parallel to the axis of rotation (16).
12. Device (10) according to one of claims 7 to 11, characterized in that the at least one pressing surface (64, 66) is supported on a holder (52) that can be pivoted around a holder axis (58) that is at an angle to the axis of rotation (16).
13. Device (10) according to claim 12, characterized in that the holder (52) is supported on a linear drive (44) that can be moved towards and away from the drive mechanism (12) in a direction that is parallel to the axis of rotation (16).
14. Device (10) according to one of the preceding claims, characterized in that the device (10) is a finishing device and that the tool (38) is a finishing tool, in particular, a finishing stone.
15. Method (10) for fine or finest processing of a rotationally symmetric work piece surface (40) of a work piece (14), with a drive mechanism (12) for driving the work piece (14) around an axis of rotation (16), with two guidance mechanisms (20, 22) acting in radial directions with respect to the axis of rotation (16), and at least one tool (38) acting in a radial direction, with a pressing mechanism (42) for pressing the work piece (14) against the drive mechanism (12), wherein the work piece (14) is disposed between the drive mechanism (12) and the pressing mechanism (42) as seen in the direction of the axis of rotation (16), characterized in that the pressing mechanism (42) is positioned in a pressing plane (74) that is offset from the axis of rotation (16) towards a space (78) in which the guidance mechanisms (20, 22) are disposed, such that the pressing plane (74) is positioned eccentrically relative to the axis of rotation (16) and thus offset toward the two guidance mechanisms (20, 22).

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