Abstract
A thermally coated component is disclosed. The thermally coated component has a frictionally optimized surface of a track for a friction partner, where the surface has pores. The pores have an entry rounding, the slope of which, as a ratio of the depth of the entry rounding to a longitudinal section of the surface or parallel to the surface, has a value of more than 2.5 m/mm.
Claims
1-7. (canceled)
8. A thermally coated component, comprising: a surface of a track for a friction partner, wherein the surface has a pore, wherein the pore has an entry rounding, and wherein a slope of the entry rounding, as a ratio of a depth of the entry rounding to a longitudinal section of the surface or parallel to the surface, has a value of more than 2.5 m/mm.
9. The thermally coated component according to claim 8, wherein an average slope for a plurality of pores of the surface is more than 3 m/mm.
10. The thermally coated component according to claim 8, wherein the surface has been mechanically treated.
11. The thermally coated component according to claim 10, wherein the surface has been mechanically treated by cutting.
12. The thermally coated component according to claim 8, wherein the surface has been treated by honing.
13. The thermally coated component according to claim 8, wherein the surface has been treated with a tool having diamond honing stones and with a tool having ceramic honing stones.
14. The thermally coated component according to claim 8, wherein a thermal coating of the thermally coated component is a thermal spray coating.
15. The thermally coated component according to claim 14, wherein the thermal spray coating is an are wire spraying layer or a plasma transferred wire arc (PTWA) layer.
16. The thermally coated component according to claim 8, wherein the thermally coated component is a cylinder crankcase or a piston or a hush or a cylinder liner.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 illustrates a surface having an exemplary pore;
[0021] FIG. 2 shows the pore from FIG. 1 having a boundary line between the rounding of the pore and the surface surrounding the pore;
[0022] FIG. 3 is a schematic diagram of a cross section through the part of a pore to visualize the entry rounding;
[0023] FIG. 4 is a sectional enlargement with marked tangents and measuring sections for the first method according to the invention;
[0024] FIG. 5 is a pore having two boundary lines to clarify the second method according to the invention;
[0025] FIG. 6 is a schematic diagram of a cross section of the pore having the two boundary lines according to FIGS. 5; and
[0026] FIG. 7 is a diagram with slope values for different pores which have been treated in different ways.
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] in the depiction of FIG. 1, a pore 1 in a thermally sprayed frictionally optimized surface 2 is shown purely by way of example. The depiction of FIG. 1 converted to greyscale originates from white-light interferometry and shows different colors or just different shades of grey depending on the height of the material. The depiction in FIG. 1 thus finally portrays a three-dimensional topography of the measured surface 2 having the pore 1 and the surface 2 surrounding the pore 1. In particular, this three-dimensional image of the topography of the surface 2 can then be further processed using image processing methods. In the depiction of FIG. 2, the pore 1 can be seen again similarly to the depiction in FIG. 1 on the left-hand side of the depiction of FIG. 2. In contrast to the depiction in FIG. 1, a boundary line 3 is marked here and is depicted again separately in the right-hand depiction of FIG. 2. This boundary line 3, which could also be referred to as the first boundary line, as shown again later, thereby separates the region of a so-called entry rounding 4, which can be recognized in the depictions of FIGS. 1 and 2 in corresponding shades of grey, from the surface 2 surrounding the pore 1. In addition, an average height level for the surface 2 surrounding the pore 1 is firstly determined by means of white-light interferometry. Points belonging to this pore 1 are then determined, the points being lowered with respect to this average height level by the double resolution limit and adjoining the surrounding surface. These points then form the boundary line 3 of the pore 1 with respect to the surface 2.
[0028] In the depiction of FIG. 3, this is depicted again in a schematic sectional view of a side of the pore 1. The measurement is therefore selected in m in the y direction and mm in the x direction, whereby a distorted image results. This is required, however, for the visualization of the entry rounding. The pore 1 is to be recognized as a partial recess in the surface 2 of the material referred to by 5, for example a thermally sprayed coating. A connection of the actual pore 1 to the surface 2 can thereby be recognized with a solid line which shows a relatively flat transition of an edge 6 of the pore 1 into the region of the entry rounding 4 and thus into the surface 2. A relatively smooth transition of the pore edge 6 into the entry rounding 4 is thus shown with the solid line. A further entry rounding 4 is shown with the dashed line, which is referred to in the depiction of FIG. 3 by 4, the entry rounding being much sharper in the transition to the pore edge than the entry rounding referred to by 4.
[0029] The entry rounding 4, 4 can now, depending on how it turns out, indeed have an influence on the function of the component or the coating 5. It is therefore desirable to metrologically determine this entry rounding 4, 4 as one of the parameters of the surface 2. Based on the image depicted in FIG. 2, a so-called slope of the entry rounding 4, 4 can now be determined with corresponding image processing methods, by applying, for example, as is indicated in the depiction of FIG. 4, a tangent which is referred to by T, to one, in particular however for each point, of the boundary line 3. A measuring section M of a defined length is formed perpendicularly to this tangent T, wherein the length thereof is determined symmetrically to the boundary line 3 both in the direction of the pore and in the direction of the surroundings. In the case of the structures considered here as an example, the total length of the measuring section M is 60 m. Then, starting from the beginning of the measuring section M outside the boundary line 3 inwards in the direction of the pore 1, the average increase, for example with a linear regression method, is detected along the measuring section M. If this increase is now determined along the boundary line 3 at several, in particular in all, points of this boundary line 3, then a corresponding average value can be formed such that a corresponding average increase of the entry rounding 4 of the pore 1 can be obtained.
[0030] This average increase is then formulated as a so-called slope of the entry rounding 4, 4. Therefore, calculation is carried out with the coordinates x and y marked in FIG. 3, by using the ratio of the measured depth y of the entry rounding 4, 4 with respect to the surface 2 surrounding it, proportionally or normalized to an average longitudinal section x parallel to the surface 2 (corresponding to the average value of all projections of all measuring sections M). The following formula results:
A=y/x in [m/mm].
[0031] The value of the slope A is preferably specified in m/mm of the longitudinal section x in the direction of the surface 2. The bigger this value is, the smoother the transition is from the pore surface 6 to the surface 2. A correspondingly smooth transition corresponds to the depiction of FIG. 3, which is not to scale, of the entry rounding referred to by 4. If the value of the slope is smaller, then the transition to the pore edge 6 is less smooth and could correspond, for example, to the transition referred to by 4 in the depiction of FIG. 3.
[0032] Based on the values for the slope A obtained in this way, for example the slope A of pore 1 or the average slope A for all pores 1 of a surface section or the whole surface 2 the geometry of the entry roundings 4, 4 can be compared correspondingly very easily, which facilitates the function-oriented measurement of the surface 2 and a good comparability of the surface 2 is enabled by means of the measured entry rounding shown in the figures via the average slope A in m/mm, for example after treatment with different tools and/or different coatings 5.
[0033] In order to facilitate a boundary of the measuring section M, in addition to the boundary line 3, a pore edge line 7 can be created which separates the region of the entry rounding 4, 4 of the pore 1 from the pore 1 itself. This pore edge line 7 then forms the inner boundary of the measuring section M perpendicularly to the tangent T. To clarify, such a pore edge line 7 is marked in the depiction of FIG. 6.
[0034] If the pore edge line 7 runs at a height level as in this case, just as the first boundary line 3, it can also be used for an alternative method for determining the increase of the entry rounding 4, 4. In this case, the pore edge line 7 forms a second boundary line 7, while the boundary line 3 forms a first boundary line 3. In this case, it must be ensured that both boundary lines 3, 7 run at the same (average) height level in relation to the surface 2. This then results in the exemplary course shown in the sectional depiction of FIG. 6, in which course the first boundary line referred to by 3 in the depiction is at the level of the surface 2, while the second boundary line 7 is indicted below by a certain section of the height y. if one now determines the average spacing x of these two boundary lines 3, 7 over the whole circumference of the pore 1 and, at the same time, the height difference y between the two boundary lines 3, 7, an increase or the slope A=y/x can be calculated from these values.
[0035] The method can be used as an alternative to the aforementioned method and can be quicker than the abovementioned method, depending on image processing, if required, and correspondingly takes less computing power. Otherwise, it is also the case here that a corresponding method can be carried out for each pore and that, correspondingly for the whole surface 2 or for sections of the surface 2, the rounding of the respective pores 1 is available individually or as an average value in order to carry out a function-oriented assessment of the surface 2. It is of course also possible, instead of two boundary lines 3, 7, to use more than two boundary lines and/or assess some of the pores 1 using the first method described and other pores 1 using the second method described with respect to the slope A of their entry roundings 4, 4.
[0036] The slope A can now additionally be used in particular to assess the tribological characteristics of the frictionally optimized surface 2. In the diagram of FIG. 7, the average slopes A are plotted for individual pores I treated with different production methods. The pores 1 are therefore located in a thermal coating 5 which is applied to a cylinder liner or a cylinder housing for a combustion engine of a motor vehicle. The average slope A of pores 1 is determined by means of the method described above, after the pores 1 have been honed in the usual manner with a diamond honing tool. These average slopes A of the surface 2 honed with diamond tools can be found to the far right in the diagram of FIG. 7. They have values between 1 and +1.5 for the slope. These values are therefore relatively low, Which speaks for a fairly sharp-edged transition of the pore edge 6 into the region of the rounding 4. The rounding for these pores 1 of the surface 2 which have only been treated with diamonds would thus correspond to the entry rounding 4 from the depiction of FIG. 3. The negative measurement value therefore has to do with the fact that, here, material has been found piled up in the region of one of the pores I such that a negative slope has resulted.
[0037] In the diagram of FIG. 7, the measurement values of five pores can be found at the far left which have been achieved in the surface 2 after treatment with diamond honing tools and a subsequent post-treatment with tools having ceramic honing stones. The slope values are all significantly above 2.5 m/mm, in particular above 3.5 m/mm, and in most cases even above 4. Such high slope values, which speak for a correspondingly smooth transition of the pore edge 6 into the entry rounding 4, are designed, for example, as is indicated in the depiction of FIG. 3 as an entry rounding 4. Such a design of the pores 1 then enables a correspondingly high oil holding volume such that the best tribological characteristics for the frictionally optimized surface 2 can be achieved.
