WORKPIECE HOLDING DEVICE

Abstract

A workpiece holding device for holding a workpiece having a substantially radial inner surface and a substantially radial outer surface in a heat treatment system while the workpiece undergoes a thermal expansion and/or contraction, the workpiece holding device includes at least two clamping units configured to apply a radial clamping force to the workpiece to hold the workpiece in the workpiece holding device in a predefined position, each of the at least two clamping units including a clamping element configured to abut against the radially inner surface and/or against the radially outer surface of the workpiece and to apply a radial clamping force to the workpiece.

Claims

1. A workpiece holding device for holding a workpiece having a substantially radial inner surface and a substantially radial outer surface 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 clamping force to the workpiece to hold the workpiece in the workpiece holding device in a predefined position, each of the at least two clamping units including a clamping element configured to abut against the radially inner surface and/or against the radially outer surface of the workpiece and to apply a radial clamping force to the workpiece.

2. The workpiece holding device according to claim 1, including drive unit configured to rotate the workpiece held in the workpiece holding device, the drive comprising a friction wheel or a friction roller configured to abut against the workpiece and such that a rotation of the friction wheel or the friction roller is frictionally imparted to the workpiece.

3. The workpiece holding device according to claim 1, wherein the clamping element is configured as a slide shoe having a contact surface abutting against the radially inner surface and/or radially outer surface, the contact surface having a curvature adapted to a curvature of the radially inner surface and/or the radially outer surface.

4. The workpiece holding device according to claim 1, wherein the clamping element is configured as a rotatable clamping element configured to abut against the workpiece, the rotational axis clamping element being configured substantially parallel to an axis of rotation of the workpiece.

5. The workpiece holding device according to claim 4, wherein the rotatable clamping element has a cylindrical, conical, convex, and/or spherical shape.

6. The workpiece holding device according to claim 4, wherein the rotatable clamping element is configured to make line contact with the workpiece along a line parallel to the rotational axis.

7. The workpiece holding device according to claim 4, wherein the rotatable clamping element comprises a slide-on sleeve releasably mounted on a journal of the clamping unit.

8. The workpiece holding device according to claim 4, wherein the clamping unit furthermore comprises a setting device that is configured to set an angular setting of the rotating clamping element.

9. The workpiece holding device according to claim 4, including at least three support units configured to axially support the workpiece, the support units each including at least one rotatable support element against which workpiece lies.

10. The workpiece holding device according to claim 9, wherein the rotatable support element is a sleeve releasably attached to the support unit and having a cylindrical, conical, spherical, and/or toroidal outer surface.

11. The workpiece holding device according to claim 9, wherein at least one of the clamping units and one of the support units are disposed on a same carrier, wherein the rotatable clamping element and support elements of the clamping unit and support unit disposed on the common carrier are configured as a combined rotatable element.

12. The workpiece holding device according to claim 9, wherein the rotatable clamping element of one of the at least two clamping units is actively driven to frictionally impart rotation to the workpiece or at least one of the rotatable support elements is actively driven to frictionally impart rotation to the workpiece.

13. The workpiece holding device according to claim 4, wherein the clamping element is configured to abut against the workpiece with a predetermined contact force and to maintain the predetermined contact force while the workpiece thermally expands and contracts.

14. The workpiece holding device according to claim 13 including a controller configured to control the contact force.

15. The workpiece holding device according to claim 4, wherein at least one clamping unit includes a force measuring device configured to measure a clamping force of the clamping unit on the workpiece, and wherein the force measuring device is configured to communicate with the controller.

16. A method comprising: providing a workpiece holding device according to claim 1, mounting the workpiece in the workpiece holding device, moving the at least two clamping units into contact with the workpiece to clamp the workpiece with a predetermined clamping force, 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 while performing the thermal treatment, adjusting the at least two clamping units to maintain the predetermined clamping force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] 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.

[0071] FIG. 2 is a schematic depiction of a workpiece holding device according to a preferred exemplary embodiment of the present disclosure.

[0072] FIG. 3 is a schematic depiction of a clamping possibility of clamping units in the workpiece holding device according to FIG. 2.

[0073] FIG. 4 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0074] FIG. 5 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0075] FIGS. 6a-6f are schematic depictions of various exemplary embodiments of clamping elements usable with the workpiece holding devices of the disclosed embodiments of the present disclosure.

[0076] FIGS. 7a-7d are schematic depictions of various clamping possibilities.

[0077] FIGS. 8a-8c is schematic depictions of various further clamping possibilities.

[0078] FIG. 9 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0079] FIG. 10 is a schematic depiction of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

[0080] FIGS. 11a and 11b are schematic depictions of a workpiece holding device according to a further preferred exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

[0081] In the following, identical or functionally equivalent elements are designated by the same reference numbers.

[0082] 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 along the inductor 4. The workpiece holding device 6 has clamping units 8-1, 8-2, 8-3 for holding the workpiece 2, which are designed to hold the workpiece 2.

[0083] Furthermore, FIG. 1 shows that in the exemplary embodiments depicted, the workpiece 2 lies against three support units 12-1, 12-2, 12-3.

[0084] Now instead of, as in the prior art, rotating the entire system 6 in order to move the workpiece 2 along 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.

[0085] 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 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.

[0086] 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 configured 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.

[0087] FIG. 2 shows a schematic-perspective view of a first preferred exemplary 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 (pivotably) 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.

[0088] Furthermore, it can be seen from FIG. 2 that in the region in which the workpiece 2 lies against the carrier 60, 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. Due to rotatability of the 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.

[0089] Of course, more support elements 16, or all support elements 16, can also be actively driven.

[0090] Furthermore, FIG. 2 shows that on the carriers 60, 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.

[0091] As depicted in FIG. 2, the clamping units 8 include clamping elements 10 in the form of clamping cylinders 10. The clamping elements or clamping cylinders 10 can be configured as sleeves releasably, and preferably rotatably, slipped onto hubs 63. Here it is advantageous in particular when the clamping element 10 is configured to be radially displaceable, together with its hub 63, along the carrier 60 or the shaft 62, in order to be adapted to different workpieces, or in order, for example, to exert a clamping force on a radial inner surface 24 of the workpiece 2 instead of the clamping force depicted here on a radial outer surface 22 of the workpiece 2.

[0092] Here it is preferred in particular when the clamping elements 10, as depicted in FIG. 6, are configured as slide-on sleeves. Here the slide-on sleeve 10 can have a cylindrical (FIGS. 6a, 6b), conical (FIG. 6c-6e), convex (FIG. 6f) and/or spherical shape. The exact shape can depend on a plurality of factors. On one hand, the shape can be adapted to the shape or curvature of the radially inner or outer surface 22; 24 of the workpiece 2. Here it is preferred in particular that the slide-on sleeve contacts the workpiece 2 along a line, wherein the line is oriented parallel to the rotational axis. This makes possible a pure rotational movement between rotating element and workpiece without sliding movement. However, it is equally possible to select the shape based on a minimal contact but sufficient clamping force. The shape can also be selected based on rotation considerations. Furthermore, it is possible that the clamping units 8-1-8-4 include differently designed slide-on sleeves.

[0093] According to a further preferred exemplary embodiment, the hub 63 can also be set angularly with the aid of a setting device (not depicted), as also schematically indicated in FIG. 6b. This also makes possible a particularly good adapting of the rotating elements to the geometry of the workpiece. Thus, with the aid of the adjusting device, it is possible, for example, to use a cylindrical rotatable element also for obliquely extending radial surfaces and still guide the rotating element along the workpiece with linear contact. Alternatively, a conical sleeve could also be used here as depicted in FIGS. 6c to 6d.

[0094] Alternatively or additionally, one of the clamping units, for example, 8-3, can function as the drive unit 14, and then carries a friction roller 18 instead of a clamping cylinder 10-3, which frictionally abuts against the workpiece 2 and is actively set in rotation in order to rotate the workpiece 2. The driven clamping roller/friction roller 18 can be present alternatively or in addition to a driven support element 16. The friction roller 18 can also have a cylindrical, conical, convex, toroidal, and/or spherical shape, as depicted in FIG. 6.

[0095] 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 support elements 16, into a closed position in which the workpiece is clamped in the clamping units 8, and they 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.

[0096] 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 center of rotation 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 embodiment 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.

[0097] 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.

[0098] 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 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 support elements 16 or into the clamping elements 10 8 in order to set the workpiece 2 in rotation.

[0099] The clamping units 8 can in turn also include slidable-on 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. These can also have various shapes, as depicted in FIG. 6.

[0100] The rotatable support elements 16 of the support units 12 can also be formed as exchangeable sleeves with the shapes shown by way of example in FIG. 6. The can thereby on the one hand ensure a low-friction and tilt-free supporting of the workpiece and simultaneously ensure a particularly good accessibility to the surfaces to be treated. On the other hand, the flexible design also allows adaptation to the shape of the workpiece itself via the exchangeable sleeves.

[0101] FIG. 5 shows a further preferred exemplary embodiment in which the rotatable support element 16 and a clamping unit 8 formed as 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. With rotating of the support element 16 about 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 support element 16 is also transmitted via the friction wheel 18 onto the workpiece 2 so that the workpiece 2 is also rotated.

[0102] As schematically depicted by arrows in FIG. 7, in order to apply a balanced-as-possible clamping by the clamping units 8 onto the workpiece 2, at least two application points, preferably three application points (see FIG. 7a) are provided for the clamping force. However, more than three application points, for example, four (see FIG. 7b) or five (see FIG. 7c) application points, can also be present. As can be seen in particular from FIGS. 7a and 7d, the application points can be provided both from radially outward and radially inward, wherein a clamping from radially inside or from radially outside can also be chosen in a manner depending on the surfaces to be hardened. Thus, for example, in the case of a bearing inner ring in which the radial outer surface is to be hardened, it is preferred to provide a clamping from radially inside since this surface is facing away from the surface to be heated and then the clamping elements are not also heated. Similarly, with an outer ring to be hardened (see FIGS. 7a-c) it is advantageous to allow the clamping elements to grip from radially outside, i.e., also on the surface not to be hardened.

[0103] In addition to the radial clamping units 8 as depicted in FIGS. 1 to 4 and 6, so-called hold-down clamps 19 (see FIG. 8) can also be used that apply an axial clamping onto the workpiece 2. The axial clamping elements 19 can simultaneously also be configured as drive units and, for example, frictionally abut against the workpiece so that it can be set in motion. These hold-down clamps 19 are used in particular with light workpieces and high magnetic field strengths of the inductor 4 in order to hold the workpiece in the workpiece holding device 100 securely and in a positionally accurate manner. Exactly like the support units 12, the axial hold-down clamps 19 can be combined with the elements of the radial clamping, as depicted in the Figures of FIG. 8, and can be provided in the same location (see FIGS. 8a, 8c) or at different locations (see FIG. 8b). Of course, it is also possible to provide a different number of axial clamping elements and radial clamping elements.

[0104] Instead of only one clamping cylinder each, as depicted in FIGS. 1-8, the clamping units can also include double clamping cylinders as depicted in FIGS. 9 and 10. Here also, one or more of the clamping cylinders 10 can simultaneously be configured as a drive 14, or a separate drive can be possible. The embodiment using such clamping elements leads to a particularly low-deformation clamping with ovality, out-of-roundness, triangularity, or other shape deviations of the workpiece.

[0105] FIG. 11 shows two different views of a further exemplary embodiment in plan view (FIG. 11a) and side view (FIG. 11b), wherein the clamping unit 8 can include so-called slide shoes 50 against which the workpiece 2 is supportively guided. The slide shoes 50 can preferably abut against an axial end surface of the workpiece 2, whereby rings that are twisted or wavy in themselves can also be supported. The slide shoes 50 can be embodied flat. However, it is also possible to provide a roller bearing, as depicted in particular in the side view. It is advantageous in particular with a supporting of an inherently wavy workpiece on slide shoes 50, as depicted in FIG. 11, to provide a separate drive unit 14, as depicted in FIG. 11a.

[0106] In general, the clamping units do not also need to be disposed equidistantly around the workpiece, but rather it is possible to choose different spacings of the clamping units. It is also possible that the clamping device 8 is not itself provided as a drive unit, but rather, for example, a separate drive unit 14 (see FIGS. 1, 11) is provided, or one of the support units 12 serves as drive unit.

[0107] Overall, the flexible design of the clamping units and support units makes possible a particularly good adapting of the workpiece holding device to various shapes of the workpieces. An individually adjustable device can thereby be provided, which, however, is universally usable for a variety of workpieces.

[0108] 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.

[0109] 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 device.

[0110] 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.

[0111] 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.

[0112] 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

[0113] 100 Hardening system

2 Workpiece

[0114] 4 Induction coil
5 Main body
6 Workpiece holding device
8 Clamping unit
10 Clamping element
12 Support unit
13 Measuring device
14 Drive unit

15 Controller

[0115] 16 Support element
18 Friction roller
19 Hold-down clamp
22 Radially outer side of the workpiece
24 Radially inner side of the workpiece
50 Slide shoes

60 Carrier

[0116] 62 Rod-shaped shaft

63 Hub

[0117] 64 Bearing assembly