Method for producing a stop disk and a stop disk produced by means of this method

Abstract

The invention relates to a method for producing a stop disk (2). The method comprises cutting out a partial external preliminary contour (4) of the stop disk (2) from a sheet material, wherein the stop disk (2) still remains connected to the sheet material after the cutting-out process, embossing an edge (6), wherein the thickness of the sheet material of the stop disk (2) is reduced in the region of the partial external preliminary contour (4), embossing a running surface profile (32) in a region, which does not belong to the edge (6), in order to form a running surface (8 / 22), cutting out the stop disk (2) from the sheet material.

Description

[0001] Method for Producing a Stop Disk and a Stop Disk Produced by means of this Method

[0002] The present invention relates to a method for producing a stop disk or a thrust bearing, respectively, and a stop disk produced by means of this method or a thrust bearing produced by means of this method, respectively.

[0003] In the automotive sector, stop disks are used especially in the area of crankshaft bearings in order to transmit in particular smaller axial loads between crankshaft and the engine block. The stop disks are used here so as to connect to the bearing shells of the crankshaft bearings. The stop disks present here are embodied as lubricated sliding bearings.

[0004] Modem stop disks comprise a sophisticated running surface geometry, which can comprise a contour with a contour depth in the axial direction in the range of over approx. 100 pm. A contour depth can be larger in regions, which do not serve as running surface. The bearing surfaces have to have a high quality with regard to the surface quality thereby in order to prevent damage to the running surface during operation. So far it is only known to machine the running surfaces with contour depths of above approx. 75 pm in the axial direction of profiled stop disks.

[0005] It is desirable to be able to produce stop disks much more easily, more quickly and especially more cost-efficiently than it is possible with the conventional methods.

[0006] According to one aspect of the present invention, a method for producing a stop disk, comprising cutting out a partial external preliminary contour of the stop disk from a sheet material is provided, wherein the stop disk still remains connected to the sheet material after the cutting-out process, and an edge around the sheet material of the stop disk is further preembossed in order to thin out an edge region, wherein material of the outer preliminary contour of the stop disk flows at least partly into the cut-out regions in response to the thinning out. A running surface profile is subsequently embossed into a region of an edge of the stop disk, which was not thinned out, in order to form a running surface. Finally, the stop disk is cut out from the sheet material. A portion of the partial external preliminary contour is preferably likewise cut out to form an end contour in response to the cutting-out process and the webs, which connect the stop disk to the sheet material, are also severed.

[0007] The stop disk is preferably made of a sheet material, which is present in a sheet coil. Such a coil sheet material is preferably processed with the help of transfer punching pressing machines, upstream of which a straightening section can also be connected.

[0008] The partial external preliminary contour of the stop disk is preferably cut out from a sheet material by means of punching out, wherein a distance from the punching residue, which has a minimum width, is present next to the edge. The punching out of the partial external preliminary contour of the stop disk from a sheet material preferably comprises several separate punching steps, in order to keep the punching force low for each punching step.

[0009] After the cutting-out process, the stop disk still remains connected to the sheet material, in order to transport the stop disk with the sheet material to a processing station, without having to handle individual stop disks. All of the sheet material is in each case moved further here for each processing step in a pattem / repeating pattern, in order to be further transported to a next processing station in a transfer punching press. Instead of many individual transport and handling devices, only one transport device can be used here for the band-shaped sheet material. Due to the use of a transfer press, a stop disk can be finished in response to each stroke of the press / punch. The connection of the stop disk to the sheet material essentially has the shape of webs. In one embodiment, two webs at the two ends of an essentially circular arc-shaped stop disk are used.

[0010] The occurring punching forces in the case of punching presses depend on the material parameters of the sheet material and the thickness of the material and are likewise linearly dependent on the length of the punching line. A punching device, which punches out a region with several steps or sections, respectively, has the advantage that these individual steps can be distributed over the operating travel of the punch and the total punching force can thus also be distributed to different sections of the operating travel in response to a simultaneous punching of several steps.

[0011] After the external preliminary contour is cut free or punched out, respectively, an edge region of the stop disk can be leveled by means of an embossing / pressing step, wherein the material of the stop disk can flow into the cut-out region next to the external preliminary contour perpendicular to the embossing direction. Due to the free region next to the external preliminary contour, the shaping forces in the case of this step can be kept small, compared to an embossing without a clearance next to the edge. This step influences the shape of the external preliminary contour, which becomes larger due to the displaced material. The stop disk now essentially has the shape of a table mountain.

[0012] The embossing or pressing of the edge is preferably carried out by the later running surface, in order to obtain an essentially smooth and flat rear side, which lies opposite the running surface. It can likewise be provided that a rear side of the edge is also slightly offset or embossed, respectively, in order to consider a material distortion in response to later processing steps, such as the shaping of the running surface profile or the final cutting-out process of the stop disk from the sheet material. Deformation occurring later can be considered here by means of a skillful selection of the embossing, so that desired tolerances with respect to a flatness of the rear side can also be maintained without a finishing.

[0013] The running surface profile is embossed in the region of the stop disk, in which the thinned- out edge does not extend. In analogy to the table mountain, the peak plateau is now provided with a height profile. The profile has elevations and depressions in the axial direction, which are typically designed as lubricant grooves or gradients. A profile height in the axial direction can be in the range of 50 to 500 pm thereby. By embossing the running surface, the latter is additionally cold-worked.

[0014] The cutting-out process of the stop disk from the sheet material thereby essentially comprises a severing or regions of the partial external preliminary contour of the stop disk, which were not cut out originally. It is likewise possible to sever a portion of the flattened edge region of the stop disk, wherein lower cutting forces occur here because the material has a smaller thickness due to the embossing of the edge. A severing of the edge can be expedient in order to provide an edge contour, which is less well defined due to the pressing, with dimensions, in order to be able to reliably maintain desired tolerances.

[0015] In an exemplary embodiment, only the edge contour is embossed or pressed, respectively, without a portion of the running surface being embossed or pressed. It is likewise possible to emboss particularly deep sections of a running surface profile, such as lubricant channels, in response to the pressing or embossing, respectively, of the edge contour.

[0016] The embossing of the running surface contour can likewise take place in several steps. Due to cold compressing, an embossed running surface has a higher stability and due to the embossing, a profile with elevations and depressions as well as lubricant channels can be produced in the radial and circumferential direction.

[0017] It is likewise possible to embody the stop disk as stamped and bent part, wherein portions are embodied as flags or flaps and are in each case bent over directly prior to or after the embossing of the running surface contour or of the running surface profile, respectively, or the cutting-out process of the stop disk from a plane of the sheet material or of the stop disk, respectively.

[0018] According to a further embodiment of the production method, the latter further comprises a coating of the embossed running surface. The coating can be performed thereby prior to the separation of the stop disks from the sheet material, wherein the coating can be integrated directly into the transfer punching press, for example by means of a polymer film. The coating can likewise be carried out after the separation of the stop disks from the sheet material in a downstream coating device. A downstream coating has the advantage that coating methods, which require a longer dwell time, such as drying times, for example, can also be used. A polymer coating with a thickness of between 2 and 25 pm, preferably between 3 and 20 pm, and more preferably between 5 and 15 pm, is applied, wherein the polymer layer has a smaller coefficient of friction and serves as bearing material for the stop disk. It is provided to apply the polymer coating as film or as varnish layer or to apply it to the embossed running surface via thermal transfer. Such a coating can be applied, for example, by means of a screen printing process. It is likewise possible to spray on a coating. A stencil can preferably be used during the coating, in order to define the region, in which coating takes place. Polyamide imides (PAI), which can also comprise fillers, such as, for example, BN (boron nitride) or M0S2 (molybdenum disulfide), are suitable as thermoplastic coating material.

[0019] In the case of a further exemplary embodiment of the method, a polymer coating is essentially applied in a holohedral manner on the side of a later running surface prior to cutting out the partial external preliminary contour of the stop disk. In particular PTFE can be used as film or fluid here. It is also possible to use a thermoplastic with matching fillers as a coating material. Polyamide imides (PAI) are suitable as thermoplastic coating material. For example, BN (boron nitride) or M0S2 (molybdenum disulfide) are suitable as fillers for the printed-on polymer coatings as well as thermoplastic layers.

[0020] In one embodiment of the method, the polymer coating is applied only in the region of the running surface. No polymer coating is thereby applied in a region next to the embossed running surface as well as in the region of the channels in the embossed running surface. It is provided, however, that the polymer coating also extends up to 1 mm, preferably only up to 0.4 mm, more preferably only up to 0.1 mm, into the channels over an edge of the running surface. Such an embodiment is suitable in particular for liquid applied polymer coatings. It can likewise be provided that the polymer coating ends up to 1 mm, preferably only up to 0.4 mm, more preferably only up to 0.1 mm, in front of an edge of the embossed running surface. Such an embodiment is suitable in particular for film-based or thermally applied polymer coatings.

[0021] In a further embodiment of the method, the latter further comprises at least one leveling step in order to eliminate deformations of the stop disk after the embossing of the running surface prior to the final punching out of the stop disk and to smoothen out the stop disk.

[0022] According to a further aspect of the present invention, a stop disk is provided, which was produced by means of the above-described method.

[0023] In the case of one embodiment of the stop disk, the latter does not have a chamfer or bevel, respectively, between the running surface and the edge, but is provided with at least one step. On principle, at least one step is present, which is at hand due to the embossing of the edge after the cutting-out process of the external preliminary contour. It can also be provided to emboss the edge in several partial embossing steps, wherein a further step is preferably created in response to each partial embossing step. Further steps can additionally be added in response to the embossing or shaping, respectively, of the running surface profile. A special aspect lies in that embossing indents are present on the flanges, which do not occur in response to a machining. In the case of this shape, the thinning of the edge is required prior to the embossing of the running surface because a step can be embossed much more easily here than a slope or bevel, respectively. In this embodiment, the slope or chamfer, respectively, or the bevel, respectively, represents a differentiating feature here, by means of which a stop disk according to the present invention and a stop disk produced by means of conventional machining can be differentiated. It is simpler to mill a bevel with sharp flanges by means of a contour milling table or an edge milling machine, respectively, with beveled cutter, than to create a sharp step by means of machining. In contrast, it is rather difficult to use a partial embossing method on an edge to create a bevel or a chamfer because it does not only flow outwards in the direction of an edge in response to the shaping of the sheet material but is also pushed in the direction of an upper flange, which can impact a profile of the running surface, for example, due to a bulge formed in this way. When a slope or a lead- in slope, respectively, or the like is needed at one point of a punched / embossed stop disk, the slope can be provided with a step at least on the top, optionally also on the top and on the bottom, in response to the embossing of the edge. In response to a subsequent embossing of the slope, displaced material can at least partly fill the step, without creating a bulge, which extends over a running surface profile. It is likewise possible to provide steps or embossments, in order to be able to accommodate flowing material, such as indents and the like, without burrs, indents or the like impacting a desired external contour.

[0024] According to another embodiment of the stop disk, the sheet material or the stop disk, respectively, is made of a uniform metal material. According to this embodiment, the sheet material, from which the stop disk is made, is a material of a uniform alloy. In this embodiment, the finished stop disk can also be provided with a varnishing or a coating. The base material in this embodiment is preferably an aluminum alloy or a copper-based alloy. In the case of this embodiment, the stop disk can likewise comprise coatings, varnishings or a marking.

[0025] According to a further embodiment of the stop disk, the sheet material or the stop disk, respectively, is entirely or at least largely a multi-layer material. The multi-layer material is a composite material, comprising iron or steel as base material with a casting or a coating, respectively, made of aluminum, an aluminum alloy or a different bearing metal or a bearing metal alloy. Preferably, an aluminum layer on a steel substrate is used. The aluminum layer can be cast or rolled onto the steel substrate. It is likewise provided to apply a copper alloy onto a steel substrate by means of casting, rolling or sintering.

[0026] According to an additional further embodiment of the stop disk, the latter further has a coating made of a plastic, preferably a polymer, on the bearing surface. It is possible to embody the polymer coating with a thermoplastic. It is possible to produce the polymer coating on the basis of polyamide imide. It is likewise provided to apply a thermoplastic by means of injection molding or injection, respectively. It is possible to embody the polymer coating of PTFE, polytetrafluoroethylene.

[0027] The present invention will be illustrated below on the basis of exemplary schematic figures, which are not to scale.

[0028] Figures 1 A to ID clarify the present method on the basis of the at least four steps, as they are used in the case of the present method.

[0029] Figure 2 shows a cut through an edge of a stop disk according to the invention, which has traces of different embossing steps.

[0030] Figures 3A and 3B show two different running surface profiles.

[0031] Identical or similar reference numerals are used below in the description as well as in the figures, in order to refer to identical or similar components and elements.

[0032] Figure 1 A shows a top view onto a sheet material 12, which is provided with round guide holes or positioning holes 42 here, respectively. The sheet material can also be a section of a coil made of sheet material 12, which is pushed forward in a transfer punching device. The sheet material 12 can be a continuous material thereby. The guide perforation 42 serves the purpose of transporting and of positioning the sheet material at the individual processing stations. In the region 4, the partial preliminary contour 4 can also be cut out in two or three steps, respectively. A multi-step cutting-out or punching out, respectively, can help to keep the punching forces and thus the stressing of the tool as well as of the workpiece low.

[0033] A rough shape of a stop disk 2 was furthermore cut out along a partial external preliminary contour 4 of the stop disk 2. The cut-out has a minimum width, which is significant for a next step. After cutting out the partial external preliminary contour 4 from the sheet material 12, the stop disk 2 remains connected to the sheet material 12 via two webs.

[0034] Figure IB is based on the sheet material of Figure 1A, wherein an edge 6 was embossed along the partial external preliminary contour 4 of the stop disk 2. The thickness of the sheet material 12 of the stop disk 2 was reduced significantly in this region. The minimum width of the cut-out of the partial external preliminary contour 4 is significant here because the sheet material 12 of the stop disk 2, which was embossed to form an edge, has flown into the cut-out. A flow of material requires lower embossing forces when the material can flow freely and when it does not have to displace any material.

[0035] These two first cutting and embossing steps require the highest shaping forces, while the largest tolerances are possible in the sheet plane in response to the cutting-out process of the partial external preliminary contour 4 and embossing of the edge in the method.

[0036] In a next step, a running surface profile 8 is embossed in Figure 1C in a region of the stop disk 2, which does not belong to the edge 6. The embossing of the running surface profile 8 can likewise take place in several partial steps. As suggested here, the running surface profile can comprise slopes and channels. This embossing step represents the most precise step because a profile with a profile height of 20 to 200 pm is embossed here and this region later forms the running surface of the stop disk (or forms at least a region, in which a running surface coating can be applied).

[0037] One or two flattening steps 28, which serve the purpose of smoothening out the stop disk 2 and in particular a rear side of the stop disk 2, can also be provided in Figure 1C.

[0038] Lastly, Figure ID shows the finished stop disk 2, in the case of which the edge 6 embossed in Figure IB was not severed completely and in the case of which the stop disk was separated from the sheet material 12. The edge is severed in a region of the edge, the thickness of which was reduced in response to the embossing of the edge. Cutting takes place only in the region here, the thickness of which was already reduced in the embossing step, in order to attain lower cutting forces by means of a smaller material thickness and thus fewer impacts on the stop disk.

[0039] The severing of the thinner edge requires lower forces because the thickness of the material in the region of the edge was already reduced by means of the embossing step of Figure 1 B. Due to the lower stress in response to the severing of the edge, this step no longer impacts the shape of the running surface or the running surface profile, respectively, whereby it is possible to sever the edge by means of a punching process, and no machining is thus necessary. In response to the punching, the webs, by means of which the sheet material 12 is connected to the stop disk 2, can simultaneously be severed or cut through.

[0040] Usual finishing operations, such as a removal of burrs and coating and marking steps can also follow here. It can be provided to emboss a marking. In a last step, the sheet material 12, which forms a punching residue, can be cut into sections, in order to simplify a recycling.

[0041] Figure ID shows the finished stop disk 2, which was provided with a polymer layer 44 in the region of the running surface after the severing.

[0042] Figure 2 shows a cut through an edge of a stop disk according to the invention, which has traces of different embossing steps. Several steps 36 can be seen here, which are created in response to the embossing of the edge 6 and a two-step embossing of the running surface contour. The cut, by means of which the embossed edge 6 was severed by means of the cutting-out process 10, can be seen on the far right of the edge. The cut 10 has a punch indent. Several steps 36, which have typical embossing indents, were created in response to the embossing of the running surface contour. Due to the several steps 36, a bevel 30 suggested as dashed line here, which is otherwise produced by means of a machining, can be approximated or reproduced, respectively. The shape of the bevel is usually not significant and it is necessary that the running surface does not extend all the way to the edge of the running surface but has a definitive limitation within a sliding surface, which cooperates with the stop disk. On the top of the illustration, the running surface 8 is illustrated as plateau. In the sectional view, a boundary between a substrate 24 made of steel sheet and an aluminum layer 26 is suggested by means of the dot and dash line, wherein the steel sheet ensures the stability of the stop disk, while the aluminum can provide an easier processing and customized running surface properties.

[0043] Figures 3 A and 3B show two different embodiments of running surface profiles. The cuts run around the axis, which is to be supported, with constant radius in the circumferential direction. Figures 3 A represent unrollings of the cuts through the running surface profiles, wherein the height, compared to the circumference, is illustrated in a significantly enlarged manner. The distance between two graduation marks of the ordinate corresponds to a height of 50 pm. In Figure 3A, the stop disk 2 has a running surface profile with three roof slopes 38 with a height of approximately 100 pm here. The illustrated abscissa furthermore corresponds to approximately 180° with regard to the axis of rotation of the corresponding shaft, which corresponds to a semi-annular stop disk, as it is usually combined with bearing half-shells. In Figure 3A, two lubricant channels 34 are arranged in the region between the three roof slopes 38, via which lubricant channels lubricant, in particular motor oil, can flow into a gap between stop disk 2 and corresponding bearing surface. A stop disk is illustrated in Figure 3A, which shows equally good stop properties in both directions of rotation. The stop disk of Figure 3 A can be used for both running directions and thus also on the left and right of a shaft bearing.

[0044] Figure 4B essentially corresponds to Figure 3A, wherein six ramps 40 are provided instead of 3 roof slopes. 5 lubricant channels 34, via which lubricant can reach into the bearing or stop gap, respectively, are arranged between the six ramps 40. This embodiment allows for a stop force, which is twice as large compared to the stop disk of Figure 3 A. However, this increase of the stop force or of the possible axial force, respectively, is only obtained at the expense that this stop disk can only be used for one running direction, as it is the case, for example, in the case of 4-stroke internal combustion engines. The embodiment of Figure 3B likewise requires the use of two different stop disks because each bearing is usually used with two stop disks, one on the left and one on the right of the bearing. Due to the fact that the two stop disks are to have a mirror-symmetrical profile, two stop disks become necessary, which are mirrored in the direction of rotation, whereby the ramps rise in the opposite direction.

[0045] It is pointed out that combinations of features of individual disclosed embodiments are to also be considered as being disclosed here.

[0046] List of Reference Numerals

[0047] 2 stop disk

[0048] 4 partial preliminary contour / cut out partial preliminary contour

[0049] 6 edge embossing / emboss edge

[0050] 8 running surface profile embossing / emboss running surface profile

[0051] 10 cut out stop disk

[0052] 12 sheet material

[0053] 14 substrate

[0054] 16 bearing metal coating

[0055] 18 aluminum coating

[0056] 20 polymer coating

[0057] 22 running surface

[0058] 24 substrate

[0059] 26 aluminum coating

[0060] 28 leveling step

[0061] 30 chamfer

[0062] 32 running surface profile

[0063] 34 lubricant channel

[0064] 36 step

[0065] 38 roof slope

[0066] 40 ramp

[0067] 42 guide perforation

[0068] 44 polymer coating

Claims

Claims1. A method for producing a stop disk (2), comprising: cutting out a partial external preliminary contour (4) of the stop disk (2) from a sheet material, wherein the stop disk (2) still remains connected to the sheet material after the cutting-out process, embossing an edge (6), wherein the thickness of the sheet material of the stop disk (2) is reduced in the region of the partial external preliminary contour (4), embossing a running surface profile (32) in a region, which does not belong to the edge (6), in order to form a running surface (8 / 22), cutting out the stop disk (2) from the sheet material.

2. The method for producing a stop disk (2) according to claim 1 , wherein the stop disk (2) is made of a sheet material, which is present in a sheet coil, and wherein the sheet material is preferably fed by a winder and the sheet material is aligned in response to the feeding and prior to the cutting-out process.

3. The method for producing a stop disk (2) according to claim 1 or 2, wherein the partial external preliminary contour (4) of the stop disk (2) is cut out from a sheet material by means of punching out, wherein the punching out preferably comprises a multi-step punching out of the partial external preliminary contour (4) of the stop disk (2) from a sheet material with several separate punching steps.

4. The method for producing a stop disk (2) according to claim 1 , 2 or 3, wherein the stop disk (2) is still connected to the sheet material after the cutting-out process of the partial external preliminary contour (4), and a transport of the stop disk (2) in the method is carried out by means of a transport of the sheet material.

5. The method for producing a stop disk (2) according to claim 1 , 2, 3 or 4, wherein the running surface profile (32) comprises channels for lubricant, which preferably extend at least partly over the running surface (8 / 22) in the radial direction, and wherein the running surface profile (32) comprises gradients and preferably roof slopes, which rise and fall in the circumferential direction.

6. The method for producing a stop disk (2) according to claim 5, wherein the running surface profile (32) in the region of the gradients or slopes, respectively, comprises a profile height in the axial direction of between 25 pm and 500 pm, preferablybetween 40 gm and 200 pm, and more preferably between 50 pm and 100 pm, and / or wherein the channels comprise a profile depth with respect to adjoining running surface sections of 150 pm and 800 pm, preferably between 180 pm and 500 pm, and more preferably between 200 pm and 300 pm.

7. The method for producing a stop disk (2) according to claim 6, wherein the polymer coating is applied only in the region of the running surface (8 / 22).

8. The method for producing a stop disk (2) according to one of the preceding claims 1 to 6, further comprising applying a polymer coating in a holohedral manner on the side of a later running surface (8 / 22) before the partial external preliminary contour (4) of the stop disk (2) is cut out.

9. The method for producing a stop disk (2) according to one of the preceding claims, wherein the method comprises at least one flattening step, in order to eliminate possible deformations of the stop disk (2) after the embossing of the running surface (8 / 22) and prior to the final punching out of the stop disk (2) and to smoothen out the stop disk (2).

10. A stop disk (2), produced according to a method according to one of the preceding claims.

11. The stop disk (2) according to claim 10, wherein the running surface profile (32) comprises at least one roof slope or a ramp, which falls in both directions in an angular range of approx. 15° to 30° in the circumferential direction from a highest point by 25 pm and 500 pm, preferably between 40 pm and 200 pm, and more preferably between 50 pm and 100 pm.

12. The stop disk (2) according to claim 10 or 11, wherein the running surface profile (32) forms an isosceles triangle, a flattened Tudor arch or a flattened basket arch in sections.

13. The stop disk (2) according to one of claims 10 to 12, wherein the stop disk (2) has at least one step (36) in a cross section between the running surface (8 / 22) and an edge (6).

14. The stop disk (2) according to one of claims 10 to 13, wherein the sheet material orthe stop disk (2), respectively, is entirely or at least largely made of a multi-layer material, comprising iron or steel as base material with a casting or a coating, respectively, made of aluminum or a different bearing metal, wherein the stop disk (2) preferably uses an aluminum layer or an aluminum alloy layer on a steel substrate, or wherein a copper alloy layer is applied to a steel substrate, wherein a polymer layer, which serves as running surface (8, 22), is more preferably applied to the aluminum layer, the aluminum alloy layer or the copper alloy layer.

15. The stop disk (2) according to one of claims 10 to 14, wherein the stop disk (2) further has a coating (44) made of a plastic, preferably a polymer, such as, for example, polyamide imide, more preferably made of a thermoplastic or even more preferably of PTFE, on the running surface (8, 22).

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