WORKPIECE HOLDING DEVICE

Abstract

A workpiece holding device for holding a workpiece in a heat treatment system while the workpiece undergoes a thermal expansion and/or contraction includes at least two clamping units configured to apply a radial and/or an axial clamping force to the workpiece to hold the workpiece in the workpiece holding device in a predefined position, and at least three support units configured to support the workpiece. At least one of the support units includes a carrier and an exchangeable support element attached to the carrier, the exchangeable support element being configured to contact and rotatably support the workpiece in the predefined position.

Claims

1. A workpiece holding device for holding a workpiece in a heat treatment system while the workpiece undergoes a thermal expansion and/or contraction, the workpiece holding device comprising: at least two clamping units configured to apply a radial and/or an axial clamping force to the workpiece to hold the workpiece in the workpiece holding device in a predefined position, and at least three support units configured to support the workpiece, wherein at least one of the support units includes a carrier and an exchangeable support element attached to the carrier, the exchangeable support element being configured to contact and rotatably support the workpiece in the predefined position.

2. The workpiece holding device according to claim 1, wherein a radial distance of the exchangeable support element to a center point of the workpiece holding device is adjustable.

3. The workpiece holding device according to claim 1, wherein the carrier is a shaft and the exchangeable support element is a sleeve slidably mounted on the shaft.

4. The workpiece holding device according to claim 3, wherein the at least one of the at least three support units comprises three of the at least three support units, and wherein the shafts extend spoke-like radially outward from a center point of the workpiece holding device.

5. The workpiece holding device according to claim 3, wherein the at least three shafts comprise three shafts spaced by an angle of approximately 120° or four rod-shaped carriers configured in an X arrangement.

6. The workpiece holding device according to claim 3, wherein a first one of the support units is actively drivable and configured impart rotation to the workpiece.

7. The workpiece holding device according to claim 6, wherein the exchangeable support element is a friction roller.

8. The workpiece holding device according to claim 6, wherein a weight force applied by the workpiece to the exchangeable support element determines a friction force between the exchangeable support element and the workpiece.

9. The workpiece holding device according to claim 1, wherein the at least two clamping units are each attached to a clamping unit carrier extending radially from the rotational center point of the workpiece, and wherein the at least two clamping units are each configured as a clamping element having a longitudinal axis extending substantially perpendicular to a longitudinal axis of the carrier.

10. The workpiece holding device according to claim 9, wherein at least one of the support units is connected to one of the at least two clamping unit carriers.

11. A method comprising: providing a workpiece holding device according to claim 1, applying a predetermined force to the workpiece with the at least two clamping units, rotating the workpiece in the workpiece holding device, performing a thermal treatment on at least a portion of the workpiece in the workpiece holding device, and actively or passively readjusting the clamping units during the thermal treatment to maintain the predetermined force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1 is a schematic depiction of an induction hardening system with a workpiece holding device according to a preferred exemplary embodiment of the present disclosure.

[0069] FIG. 2 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0070] FIG. 3 is a schematic depiction of a clamping possibility of clamping units in the workpiece holding device according to FIG. 2.

[0071] FIG. 4 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0072] FIG. 5 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0073] FIGS. 6a-6f are schematic depictions of various exemplary embodiments of the exchangeable support elements.

DETAILED DESCRIPTION

[0074] In the following, identical or functionally equivalent elements are designated by the same reference numbers.

[0075] FIG. 1 schematically shows a plan view of an induction hardening system 100 that is designed to inductively harden a workpiece 2, e.g., a bearing ring, with the aid of an inductor 4. Here the induction hardening system 100 depicted in FIG. 1 is formed as a hardening system in which the inductor 4 always heats only one part of the workpiece 2 while the workpiece 2 is moved past the inductor 4. For this purpose the workpiece 2 is clamped into a main body 5 of a workpiece holding device 6 and moved past the inductor 4. The workpiece holding device 6 has clamping units 8-1, 8-2, 8-3 for holding the workpiece 2 for this purpose, which are designed to hold the workpiece 2.

[0076] Furthermore, FIG. 1 shows that in the exemplary embodiments depicted, the workpiece 2 lies against three support units 12-1, 12-2, 12-3.

[0077] Now instead of, as in the prior art, rotating the entire system 6 in order to move the workpiece 2 along against the inductor 4, a drive unit 14 is now furthermore provided that is designed to rotate only the workpiece 2. Of course, more than one drive unit 14 can also be present.

[0078] Here the drive unit 14 can be, for example, a friction wheel or a friction roller that acts directly on the workpiece 2 and sets it in rotation. Instead of a separate drive device 14 as depicted in FIG. 1, one of the clamping units 8 and/or of the support units 12 can also be configured as a drive unit 14. Thus, for example, the clamping unit 8-1 can be configured simultaneously as a friction wheel or a friction roller that in turn acts directly on the workpiece 2 and sets it in rotation.

[0079] The clamping units 8, the support units 12, and/or the drive unit 14 can be moved radially, axially, circumferentially and/or tangentially in order to optimally abut against the workpiece 2. Furthermore, on one or more of the units 8, 12, 14 it is possible to attach one or more measuring devices 13 that are designed to measure a contact force and/or clamping force and/or friction force between the clamping units 8 and/or the support units 12 and/or the drive unit 14 and the workpiece 2. Furthermore, a controller 15 can also be provided that interacts with the units 8, 12 and 14 such that the units 8, 12, 14 interact with the workpiece 2 with a predetermined contact force, clamping force, and/or friction force.

[0080] FIG. 2 shows a schematic-perspective view of a first preferred embodiment of a workpiece holding device 6 that can be used in an induction hardening system 100, as schematically depicted in FIG. 1. In the exemplary embodiment depicted, the workpiece holding device 6 comprises four carriers 60-1, 60-2, 60-3, 60-4 that each carry rod-shaped, in particular cylindrical, shafts 62-1, 62-2, 62-3, 62-4. Here the carriers 60 and the shafts 62 can also be configured as one-piece integral elements. The shafts 62 and the carriers 60 in turn are rotatably attached to bearing assemblies 64 so that the carriers 60 extend offset radially outward from a rotational center M, wherein the rotational center M is determined by the rotation of the workpiece 2 in the workpiece holding device 6.

[0081] Furthermore, it can be seen from FIG. 2 that in the region in which the workpiece 2 lies against the carrier 60, exchangeable support elements 16-1, 16-2, 16-3, 16-4 are provided that in the exemplary embodiment depicted are configured as cylindrical sleeves that are rotatably disposed on the shafts 62, in particular slipped on them. Due to the rotatability of the exchangeable support elements 16, the workpiece 2 can easily be set into rotation. For this purpose one of the rotatable support elements 16 can be actively driven, that is, set in rotation, whereby the workpiece 2 is set in motion due to the friction between the support element and the workpiece 2. Of course, more exchangeable support elements 16, for example, all exchangeable support elements 16, can also be actively driven.

[0082] Here it is preferred in particular when the exchangeable support elements 16 are configured as slide-on sleeves, as depicted in FIG. 6. Here the slide-on sleeve 16 can have a cylindrical (FIG. 6a, 6b), conical (FIG. 6c-6e), convex (FIG. 6f) and/or spherical shape. The exact shape can depend on a plurality of factors. On the one hand, the shape can be adapted to the shape or curvature of the contact surface of the workpiece 2. Here it is preferred in particular that the slide-on sleeve 16 contacts the workpiece 2 along a line, wherein the line is oriented parallel to the rotational axis, in order to provide as tilt-free as possible a supporting. This also makes possible a pure rotational movement between exchangeable support element 16 and workpiece 2 without or with only minimal sliding movement. Alternatively, however, it is also possible that the sleeve 16 or its shape is optimized such that only a very small contact surface is provided (ideally by point contact), whereby, for example, the friction of the workpiece on the contact can be minimized. The shape can also be selected based on rotation considerations. Furthermore, it is possible that the support units 12-1-12-4 include differently designed slide-on sleeves 16.

[0083] Furthermore, FIG. 2 shows that on the carriers, and in particular on the shafts 62, clamping units 8-1, 8-2, 8-3, 8-4 are provided in the form of clamping elements 10-1, 10-2, 10-3, 10-4, that are designed to secure the workpiece 2 in its position. For this purpose, the clamping devices 8 can be set, for example, radially against the carriers 60 or against the shaft 62, until they contact the workpiece 2 and secure it in its position.

[0084] As depicted in FIG. 2, the clamping units 8 include clamping elements 10. The clamping elements 10 can be configured analogously to the support elements as sleeves with the shapes shown by way of example in FIG. 6, and releasably and preferably rotatably slipped onto hubs 63. Here it is advantageous in particular when the clamping elements 10 together with their hubs 63 are formed radially displaceably along the carrier 60 or the shaft 62 in order to be adapted to different workpieces 2 or in order, for example, to exert a clamping force on a radially inner surface 24 of the workpiece 2 instead of the clamping force depicted here on a radially outer surface 22 of the workpiece 2.

[0085] In addition to the radial adjustability of the clamping units 8, it can also be provided that the carriers 60 are themselves movable and can be brought from an open position in which the workpiece 2 can be placed in the workpiece holding device 6 and against the exchangeable support elements 16 into a closed position in which the workpiece is clamped in the clamping units 8 and the clamping units 8 abut against the workpiece 2 with clamping force. For this purpose the carriers 60 are rotatably supported on the carrier bearing assemblies 64-1, 64-2, 64-3, 64-4. The carrier bearing assemblies 64 are in turn disposed eccentrically with respect to the rotational center M of the workpiece.

[0086] FIG. 3 schematically shows the design from FIG. 2, and the clamping possibility corresponds to that in the exemplary embodiment depicted in FIG. 2. Since, as mentioned above, the carriers 60 are not supported in the rotational center M but rather are eccentrically supported at points 64-1, 64-2, 64-3 and 64-4, the distance between the clamping elements 10 and the workpiece 2 can be maximized or minimized depending on the position of the carriers. Thus, for example, in a so-called zero position, the distance between clamping unit 8 and workpiece 2 can be maximized so that the workpiece 2 can be inserted into the workpiece holding device 6 without it contacting the clamping unit. In the exemplary embodiment depicted, this is possible with an orientation of the carriers in the radius direction of the workpiece. That is, when the carrier is oriented precisely in the radius direction R of the workpiece 2 (see FIG. 3), the distance between workpiece 2 and clamping unit 8 is maximized. With an angular adjustment about the zero position (see arrow), the clamping unit 8 approaches the workpiece 2 until the clamping unit 8 abuts against the workpiece 2 and can exert a clamping force. This applies to the design shown in FIG. 2 or 3, in which a radially inwardly directed clamping force is applied and the clamping units 8 are disposed radially outside on the workpiece 2.

[0087] In contrast, if the workpiece is clamped with a radially outwardly directed clamping force, i.e., with a clamping of the workpiece with clamping units disposed radially inside the workpiece, the clamping is increased when the carrier is rotated toward the orientation in the radius direction. In this case, a zero position is given over a certain maximum angular displacement, in particular at 45°, of the carrier with respect to the radius orientation.

[0088] FIG. 4 shows another preferred exemplary embodiment in which the support units 12 and the clamping units 8 are attached on separate carriers 62 or 60. Here the workpiece 2 again lies against the exchangeable support element 16 and is secured in its position by clamping elements 10. In addition, FIG. 4 shows that three support units 12 or 3 clamping units 8 are provided. The drive unit 14 can in turn be integrated into the exchangeable support elements 16 or into the clamping elements 10 8 in order to set the workpiece 2 in rotation.

[0089] The clamping units 8 can in turn also include clamping cylinders 10-1, 10-2 and 10-3 that can be moved radially in order to exert a clamping on the workpiece 2 and to hold it in position.

[0090] Here too, the exchangeable support elements 16 ensure a low-friction and tilt-free supporting of the workpiece 2 and at the same time ensure a particularly good accessibility to the surfaces to be treated.

[0091] FIG. 5 shows a further preferred exemplary embodiment in which the rotatable exchangeable support element 16 and a clamping unit 8 formed as a friction wheel 18 are present as a combined element. Here the friction wheel 18 abuts against the radial outer surface 22 of the workpiece and can thus simultaneously exert a clamping force on the workpiece 2. Thus the friction wheel 18 also assumes the function of the clamping unit 8. During rotating of the exchangeable support element 16 around its longitudinal axis A, the friction wheel 18 is simultaneously rotated. Due to the abutment (friction) of the friction wheel 18 against the outer surface 22 of the workpiece, the rotational movement of the exchangeable support element 16 is also transmitted via the friction wheel 18 to the workpiece 2 so that the workpiece 2 is also rotated.

[0092] In summary, with the presented workpiece holding device it can be achieved that a particularly easy adaptability of the workpiece holding device to different workpieces to be received is achieved. Furthermore, a good contact and accessibility of the workpiece can be achieved in the workpiece holding device, wherein at the same time the workpiece is easily movable via the support unit. In addition, a clamping of the clamping elements can also be made possible without additional elements. This is achieved via the eccentric supporting of carriers that can bring the clamping units closer to or farther away from their contact surface on the workpiece.

[0093] A controller as disclosed herein may be a programmable hardware component that can be formed by a processor, a computer processor (CPU=central processing unit), an application-specific integrated circuit (ASIC), an integrated circuit (IC), a computer, a system-on-a-chip (SOC), a programmable logic element, or a field programmable gate array (FGPA) including a microprocessor.

[0094] Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved workpiece holding devices.

[0095] Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

[0096] All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

REFERENCE NUMBER LIST

[0097] 100 Hardening system [0098] 2 Workpiece [0099] 4 Induction coil [0100] 5 Main body [0101] 6 Workpiece holding device [0102] 8 Clamping unit [0103] 10 Clamping element [0104] 12 Support unit [0105] 13 Measuring device [0106] 14 Drive unit [0107] 15 Controller [0108] 16 Support element [0109] 18 Friction roller [0110] 22 Radially outer side of the workpiece [0111] 24 Radially inner side of the workpiece [0112] 60 Carrier [0113] 62 Rod-shaped shaft [0114] 63 Hub [0115] 64 Bearing assembly