Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C17/00—Sliding-contact bearings for exclusively rotary movement
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/14—Special methods of manufacture; Running-in
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
  • B23H7/26—Apparatus for moving or positioning electrode relatively to workpiece; Mounting of electrode
  • B23H7/32—Maintaining desired spacing between electrode and workpiece, e.g. by means of particulate material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
  • C25F3/00—Electrolytic etching or polishing
  • C25F3/02—Etching
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C17/00—Sliding-contact bearings for exclusively rotary movement
  • F16C17/02—Sliding-contact bearings for exclusively rotary movement for radial load only
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/10—Construction relative to lubrication
  • F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
  • F16C33/103—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C9/00—Bearings for crankshafts or connecting-rods; Attachment of connecting-rods
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C9/00—Bearings for crankshafts or connecting-rods; Attachment of connecting-rods
  • F16C9/02—Crankshaft bearings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H2200/00—Specific machining processes or workpieces
  • B23H2200/10—Specific machining processes or workpieces for making bearings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H2300/00—Power source circuits or energization
  • B23H2300/10—Pulsed electrochemical machining
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H3/00—Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2220/00—Shaping
  • F16C2220/60—Shaping by removing material, e.g. machining
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2223/00—Surface treatments; Hardening; Coating
  • F16C2223/02—Mechanical treatment, e.g. finishing
  • F16C2223/08—Mechanical treatment, e.g. finishing shot-peening, blasting
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2223/00—Surface treatments; Hardening; Coating
  • F16C2223/10—Hardening, e.g. carburizing, carbo-nitriding

Definitions

• the invention relates to a sliding surface of a sliding pair, in particular the plain bearing surface of a radial bearing, in particular the bearing points of a crankshaft in an internal combustion engine, on the one hand with respect to the engine block and on the other hand with respect to the connecting rods.
• the contact surfaces of sliding surfaces are processed so that they have small recesses, which serve as a reservoir for lubricants. These depressions are due to the normal roughness of the material of the sliding surface present, or are deliberately introduced. Because of this, the carrying portion of a plain bearing, ie the area proportion, with which the contact surfaces actually concern each other, always well below 100%, sometimes even less than 60%.
• the corresponding structuring of the sliding surfaces is achieved by special processing steps such as grinding, finishing or honing, whereby, however, the specific arrangement of the depressions can not be specified, and also the scattering with respect to the size, in particular the depth, of these depressions is relatively large. Above all, the result of the structuring also depends heavily on the experience of the executing person.
• ECM electrochemical erosion
• an electrically conductive liquid is forced through the gap between the tool and the workpiece during the entire process.
• crankshafts as workpieces
• crankshafts for passenger car engines with high numbers of cylinders it is added that during machining they are unstable and thus difficult to position and also difficult to machine during structuring workpieces.
• Diameter deviation maximum deviation from the specified nominal diameter of the trunnion
• Roundness macroscopic deviation from the circular nominal contour of the bearing journal, indicated by the distance of the outer and inner enveloping circle,
• Supporting component the bearing surface portion of the microscopically considered surface structure, which is in contact with an adjacent mating surface
• Stroke deviation dimensional deviation of the actual stroke (distance of the actual center of the crankpin from the actual center of the center bearing), the desired stroke and
• Angular deviation in degrees or as a stroke-related measure of length in the circumferential direction specified deviation of the actual angular position of the pin bearing pin from its desired angular position relative to the center bearing axis and with respect to the angular position to the other lifting bearing pin.
• the less heavily loaded subregions are either not structured at all or are less structured, which may mean that the number, size, depth or other parameters of the depressions by means of which the structuring takes place are selected to be lower, thereby reducing the structuring effort in these areas or completely eliminated, when these less stressed subregions are not structured at all.
• the middle region is preferably structured relative to the edge regions, especially if one of the two sliding surfaces of a sliding surface pairing is convexly convex in the direction of movement. Because then results in the central region of the smallest thickness of the lubrication gap forms and there the risk of dry running is greatest.
• the structure is structured as follows: In the circumferential direction, only the segment of the lateral surface of the crankpin is structured, which upon ignition of the corresponding piston and the resulting explosion pressure on the piston strongest is loaded by the connecting rod. This is preferably a range of 30 ° in the direction of rotation to 60 ° against the direction of rotation of the roller bearing, in particular 20 ° in the direction of rotation to 55 ° against the direction of rotation from the radially outermost point of the crank pin viewed from the central bearing axis of the crankshaft.
• center-pivot spigots Either only that circumferential segment of the central bearing is structured, which lies opposite the two adjacent crankpole journal in the radial direction and points away from the structured surfaces of these crankpins, wherein there is only one adjacent crankpipe journal in the first and last center-bearing journal.
• the other possibility consists of structuring the same circumferential regions on each center-pivot journal, specifically those peripheral regions which lie opposite the structured regions of all crankcage trunnions-again in the axial direction-and point away from them.
• these would then generally be three circumferential regions per center-bearing journal, in the case of a four-cylinder engine generally only two peripheral regions per central journal journal.
• This reduces the sliding friction, especially in the heavily loaded peripheral areas, where due to the heavy load, the sliding friction during operation can be several times higher than in the other peripheral areas. Therefore, despite structuring only a portion of the sliding surface, usually well below 50%, a total reduction in friction causes, which is 80 or 90% of the friction reduction, as would occur at the same level in the complete structuring of the sliding surface.
• the structuring is preferably carried out with electrochemical erosion (ECM), in particular pulsed electrochemical erosion (PECM).
• ECM electrochemical erosion
• PECM pulsed electrochemical erosion
• the latter consists in that the current application of the two electrodes, on the one hand tool and on the other hand workpiece, is pulsed.
• a periodic approach and again removal of the tool relative to the workpiece is provided synchronously, usually by vibrating movement of the tool, the current being applied at the point of the greatest approximation between the tool and the workpiece.
• the ablated metal ions are flushed out through the electrolyte pumped in between.
• a sliding pairing of two sliding surfaces moving relative to one another preferably only one of the sliding surfaces is partially structured in the above-described sense, since the structuring of the counter-surface usually also brings only a minor increase in friction reduction.
• the depressions should have a depth of at most 10 ⁇ m, in particular a maximum of 5 ⁇ m, in particular a maximum of 1 ⁇ m, since too great a depth can prevent sufficient pressure build-up of the lubricant in the region of the recess. It has also been found that the depth in relation to the largest superficial extent of the depression should be in a certain ratio, namely between 0.005 and 0.002, in particular between 0.008 and 0.012. In the area between the recesses, the surface should have a roughness, the roughness Rz is preferably less than the depth of the recesses, in particular less than 5 ⁇ , better between 1 and 4 ⁇ amounts. The area between the recesses should be at least 50% and at most 85% to achieve optimal low friction.
• the small extent of each well should be a maximum of 150 ⁇ , better only a maximum of 100 ⁇ or even a maximum of 50 ⁇ .
• the ratio of the largest to the smallest extent of the depression should be at most a factor of 10, better only a factor of 5 or even only a factor of 3.
• the area occupied by depressions surface portion of the structured surface of this should be between 1% and 30%, in particular between 10% and 20%.
• the edge of the wells ie the transition between the edges of the wells to the other surface of the sliding surface, with a rounding with a radius of at least 2 ⁇ and / or a helix angle of less than 60 ° to the top - form surface, as a result, the accumulated in the recess lubricating oil can get out of the well better.
• the object is achieved by the machine is a machine tool with a workpiece-spindle arrangement as in a lathe, which has a controlled C-axis and in which the removal tool is arranged in particular in a tool unit, which is actively movable in the X and Z directions, but in the Y direction limited mobility, in particular floating, is, in particular by +/- 100 ⁇ .
• the tool unit is limited to the B-axis rotatable and thus stored floating.
• this object is achieved in that the active surface of the tool in the direction of movement, in the circumferential direction of the rotationally symmetrical bearing surface, a range of less than 90 °, in particular particular of less than 70 °, in particular less than 60 °, in particular less than 45 °.
• the effective surface of the tool in the direction of movement, in the circumferential direction of the rotationally symmetrical bearing surface, a range of less than 90 °, in particular particular of less than 70 °, in particular less than 60 °, in particular less than 45 °.
• the effective surface of the tool is a range of less than 90 °, in particular particular of less than 70 °, in particular less than 60 °, in particular less than 45 °.
• the elevations on the effective surface of the tool should be at least a factor of 2, better by a factor of 3 higher than the maximum depth of the wells to be produced with it.
• the object is achieved in that during machining, the distance between the tool and the workpiece is alternately larger and smaller, in particular by means of appropriate vibration of the tool.
• the application of current to the tool may be pulsating (PECM) to keep the workpiece heating low, in particular in synchronism with the vibration, ie the change in distance, so that the current surge in particular at the time of the greatest approximation between tool and workpiece takes place, and thereby the extraction of the metal ions is particularly well possible.
• PECM electrochemical ablation
• spacers are preferably fastened to the tool with which the tool rests on the surface to be machined, the bearing surface, of the crankshaft.
• the spacers must be made of electrically non-conductive material.
• the spacers are formed as spacer strips, which are located at the ends of the tool in the circumferential direction.
• a flushing groove is preferably incorporated in the circumferential direction in the active surface of the tool, in which the outlet for the electrically conductive liquid, the purging electrolyte, opens, and in particular at least 1/10 mm is deep.
• the electrolyte flows in the circumferential direction to the ends of the tool, where the spacer strips cause an at least partial seal, and from there the electrolyte flows through the working gap in the axial direction to the two axial ends of the active surface of the tool.
• the continuous application of power is the Temperature of the electrolyte and / or the changing current used as a reference variable.
• the number of pulses and / or the duration of the pulses are used as the reference variable for this purpose.
• the pressure change in the supply for the electrically conductive liquid is used as the reference variable for the control of the processing, in particular for the time of the termination of the processing, because with increasing approach the tool to the surface of the workpiece, the flow of the electrolyte through the working gap is difficult and it builds up in the supply line of the electrolyte increasing pressure.
• spacers in particular the spacer strips, oscillating in their thickness variable, for example, as a piezoelectric element, and to cause an oscillating change in its thickness by appropriate current application of this element.
• Another possibility is to leave the spacers, in particular spacer strips, to be placed continuously on the surface to be machined during machining, but to fix the tool relatively movably to and guided against the spacers and to oscillate the tool in an appropriate manner Moving workpiece to and from this path, which he must do very quickly given a total processing time of a few seconds.
• the distance between the tool and the workpiece can be changed, ie the minimum distance during the vibration, or the current can be changed.
• the tool is best kept at a distance of 5 to 400 ⁇ m, more preferably from 10 to 100 ⁇ m, to the sliding surface to be machined.
• the tool can have on its active surface either corresponding elevations, which represent the corresponding negative structure of the surface to be achieved of the workpiece, or the tool has a smooth active surface, and the active surface is covered with a mask of electrically non-conductive material, the breakthroughs through which a current flow can take place.
• the structuring of the sliding surface and in the interior of the workpiece deburring be carried out by electrochemical removal, especially at the intersections of holes, and also at the entrance of the holes in the workpiece.
• an appropriate design of the tool may be necessary, but it requires no additional processing time.
• the machining parameters such as machining time, number of pulses, applied current, distance between tool and workpiece at the time of closest approach are preferably determined so that in the area between the recesses, the surface of the workpiece thereafter has a roughness, which is smaller than the depth the recesses to be produced and / or the roughness Rz is between 1 and 4 ⁇ .
• the supporting portion in the area between the recesses should be at the surface of the workpiece after structuring between 50% and 85%, in order to ensure despite the introduced wells still a sufficient buoyancy of the sliding surface.
• crankshaft 1 shows a crankshaft for a 4-cylinder internal combustion engine in the side view
• Figure 2a the crankshaft of Figure 1 in the axial direction, cut through one of the center bearings, a crankshaft for a 6-cylinder internal combustion engine viewed in the axial direction and cut through a center bearing, a plan view of a structured region of a sliding surface, the enlarged view of a bearing point of a crankshaft,
• Sections through recesses in the sliding surface a first procedure in the manufacture of the structuring, a second and third procedure in the manufacture of structuring, a plan view of the effective surface of the tool and an axial view in producing the structuring,
• Figure 6 an enlarged view of the tool in use on the
• Figure 1 shows a typical workpiece on which sliding surfaces 1 are to be structured for reducing friction by means of depressions, a crankshaft 2 for a 4-cylinder reciprocating engine in the side view, in which on the later axis of rotation 10 of the crankshaft five central bearings 1 b with their about cylindrical lateral surfaces are provided as sliding surfaces 1. Between each of these center bearing points 1 b, each offset radially outwards, there is one each of a total of four stroke bearing points 1 a, which likewise each have an approximately cylindrical bearing surface as sliding surface 1 for one each. have ordered connecting rods, and are connected to the central bearings 1 b cheeks 5.
• crankshaft 2 which only at their axial ends during machining in a z. B. lathe is due to their structure and thus easily possible deflection in the central region is a relatively unstable workpiece, especially when it comes to machining accuracies and approximations of a tool in the order of a few ⁇ .
• ECM electro-chemical manufacturing
• an electrode which usually represents the negative shape of the sliding surface 1 to be produced, that has elevations 26 on its active surface, as shown in Figures 5a, b, placed at a very close distance of a few ⁇ to be machined sliding surface.
• crankshafts for a four-cylinder (Fig. 2a) or a six-cylinder reciprocating engine (Fig. 2b) takes place during operation, the largest load on the crankpins 1a at the time of ignition of the gas mixture and in the short time thereafter, in which builds up the explosion pressure in the cylinder and accelerates the piston down.
• the connecting rod (not shown) then presses on the peripheral region 11a1 of the currently located overhead bearing 1a, the center of which is located in the direction of rotation 28 of the crankshaft 2 behind the point 13 of this crankcaster journal 1a that is farthest radially away from the axis of rotation 10 of the crankshaft.
• peripheral region 11a1 - depending on how generous it is interpreted - an area that may even begin just before the radially outermost point 13 and extending over an angular segment opposite to the direction of rotation 28 of eg 60 °.
• crankpin 1a this is the analogous area when it is in the highest position.
• the pressure exerted by the connecting rod transmits primarily to the corresponding crankpins, from there, however, on the cheeks 5 and at least on the two axially adjacent center pivot 1 b and less strongly on the axially farther center pivot 1 b, through the Pressure of the connecting rod on the circumferential area 11a1 opposite side with the peripheral portion 111 'are pressed into their bearing shell.
• circumferential regions 11a1 ', 11a2' of the center-bearing journal 1b which are diametrically opposite the two circumferential regions 11a1 and 11a2 are likewise heavily loaded regions.
• the heavily loaded peripheral areas are exclusively structured or structured more strongly than the rest of the peripheral area, but preferably only these areas are structured so as to be able to save processing of the remaining peripheral areas.
• FIG. 3 b further shows that only the middle width region of the bearing 1 is structured transversely to the direction of movement of the circumferential direction, that is to say in the axial direction 10. This is sufficient in many cases, especially if the bearing surface 1 - as shown in Figure 5d - is not cylindrical but slightly convex, because in sliding mating with a cylindrical bearing shell then results in the central region of the axial extent of the smallest bearing gap in Operation and thus the greatest danger of eating the camp.
• FIG. 3 a shows, in the axial direction either the entire width of the bearing 1 or only the axially middle region of the bearing 1 is structured in accordance with the invention, possibly also in addition to the structuring, which may also be zone-wise in the circumferential direction.
• the sliding surface is provided in the structured area with a plurality of very small recesses 27, as shown in the enlarged plan view of Figure 3a, since it has been found that even a regional structuring significantly reduces the friction, the non-structured area, however, contributes to Bearing load of the bearing to drop only slightly:
• recesses 27 are viewed in plan view, for example, round or elongated, for example in the form of a short groove with semicircular ends, designed, wherein the distance 21 between the recesses 27 about ten times that of round recesses 27 diameter d or elongated recesses 27 of smallest extension e corresponds.
• the area fraction of the depressions within the structured area should be in the range of 1% to 30%.
• the recesses 27 are arranged in a uniform grid, for example a diamond-shaped grid, one diagonal of which lies in the circumferential direction 28.
• the main direction of extension 20 should primarily in the circumferential direction 28 of the bearing 1, ie the later direction of rotation, and for this purpose occupy an angle of 30 ° maximum. Furthermore, it has been found that the shape and size of the depressions 27 are of great importance in achieving this goal, as illustrated in the sectional representations of FIGS. 4a, b:
• the wells should have a maximum depth of a few ⁇ , sometimes deep even under a ⁇ , as this minimizes the carrying capacity, but still a sufficient depot effect and thus a reduction in friction by itself.
• the recesses 27 may have a smallest extension e, for example in the case of round recesses 27 having a diameter d of 50 or even 150 ⁇ , so that the recesses 27 are very large and flat in relation to their depth t , which is not shown realistically in FIGS. 4a, b for reasons of clarity, because the shape of the flanks 18 of the depressions 27 is to be represented there:
• flank 18 should extend into the surface of the bearing 1 with a rounding 20 of at least a radius of two Turn over ⁇ . Both measures contribute to the fact that the lubricant received in the depressions 27 during operation of the crankshaft can be well transported away in the peripheral direction 28 by means of adhesion to the contact surface of the bearing block and thus can be transported into the bearing gap away from the recesses 27.
• FIG. 6 shows how this may also be possible in one operation together with the introduction of the depressions 27:
• a material removal takes place over the entire active surface 24 of the electrode 25, but the size of the material removal also depends on the material Distance 3 between the active surface 24 and the workpiece 2 from: Therefore, it is possible to execute the elevations 26 on the electrode 25 with a substantially greater height h than the desired depth t of the recesses 27 to be produced therewith, which results in the distance 3 between the electrode 25 and the workpiece 2 between the elevations 26 remains much larger and the material removal occurring there correspondingly lower.
• the material removal and thus the smoothing effect during the introduction of the recesses 27 in the Areas are controlled in between, of course, depending on other parameters such as current flow, material of the workpiece 2, etc.
• the tips of the microscopic surface structure present there are partially removed in the region between the depressions 27, so that the remaining valleys between them are less deep and the carrying proportion between the depressions 27 increases.
• FIGS. 5a to d show possible procedures for introducing the depressions into the surface of the bearing 1:
• the difficulty lies in the fact that at a working gap 3 between the tool 25, the electrode, and the sliding surface 1 to be machined, for example, the curvature of the active surface 24 of the tool 25 in the circumferential direction 28 coincides very precisely with the curvature of the sliding surface 1 must, in order to ensure at all points in the range of 10 to 20 ⁇ equal working gap.
• this is a great challenge, even when the tool 25 is stationary during machining relative to the bearing 1.
• the tool 25, the active surface 24 extends in the circumferential direction 28 over a circumferential angle 6, for example, 100 °, before and behind this peripheral region via spacers 16 which extend in the axial direction 10, the Z-direction, and the contact are placed on the peripheral surface of the bearing 1, thereby creating a defined working gap 3.
• a circumferential angle 6 for example, 100 °
• the bearing point 1 on the opposite side stable by means of a support 23, for example, a Lü- nice 23, radially supported.
• a support 23 for example, a Lü- nice 23, radially supported.
• either the tool 25 or the entire tool unit 14, in which the tool 25 is located either floating in the Y direction over a limited path of, for example, 50 ⁇ , because an active setting in Y-.
• Direction around such small amounts and in adaptation to the individually slightly different shaped bearing 1 is hardly possible.
• the tool 25 or the tool unit 14 is limitedly pivotable about an axis parallel to the C-axis, so that both spacers 16 can bear against the bearing point 1 nen.
• a pivotability about the B-axis makes sense, in order to ensure the contact of the active surface with the two axial ends at the bearing via spacers 16.
• the spacers 16 are preferably designed as spacer strips. These can, as can be seen in FIG. 5a, extend in the axial direction or extend in the circumferential direction, as can be seen in FIG. 5d, or they can individual, more punctual, spacers each at the corners of the rectangular active surface 24 of the tool 25 may be present.
• the active surface 24 should not be in an always the same distance, the working gap, to be machined surface of the bearing 1 during processing, but this distance should intermittently, so pulsating, change during processing, so in the state of a slightly larger Spacing the metal ions dissolved out of the surface of the workpiece 2 can be flushed out more easily by means of the electrolyte 4 pressed into the working gap 3 by the tool 25.
• spacers 16 On the tool 25 fixedly arranged spacers 16 would strike in this case at each renewed approach again on the workpiece 2, which either leads to a strong wear of the spacers 16, which still have to be electrically non-conductive material, such as plastic or ceramic , and / or leave unwanted marks on the bearing 1.
• FIG. 5a One possibility - as shown in FIG. 5a in the left-hand half of the figure - is therefore that the spacers 16 are arranged movably on the tool 25 in the radial direction. As a result, it is possible for the spacers 16 to remain permanently attached to the sliding surface 1 to be processed, and for the tool 25 to oscillate in a pulsating manner relative to the spacers 16 in the direction of the sliding surface 1 and back away therefrom.
• a variable in thickness element such as a piezoelectric element 15
• a relative movement between the consistently fixed to the sliding surface 1 abutting spacers 16 and the tool 25 is achieved.
• the back pressure created in the supply line for the electrolyte 4 could be determined by means of a pressure sensor 17 in the supply line between the pump and outlet opening in the active surface 24 for the electrolyte 4 and be used as a parameter for the control of the distance between the tool 25 and to be machined sliding surface 1, because the worse by the narrowing work gap drainage of the electrolyte will lead to an immediately higher pressure in the supply line.
• FIG. 5 d shows that, in the axial direction 10, a straight active surface 24 with the elevations 26 on the tool 25 can be selected, despite the convex contour of the bearing 1 in this direction. It can rest in the tool 25 at the axial ends via spacers 16 on the sliding surface 1. Due to the lower working gap 3 in the middle region in the axial direction, the recesses formed there will be deeper in the surface of the workpiece than in the axial end regions, which however corresponds to the load and the lowest bearing gap in later operation. In addition, it is avoided in this way to have to produce an also in this direction spherical active surface 24 on the tool 25.
• FIG. 5b shows in the lower half of the figure that with large circumferential areas to be structured it is also possible to work with a plane active surface 24, which can roll on the rotationally symmetrical bearing point 1 through circumferentially extending, lateral stop bars 16 via a desired circumferential segment.
• the workpiece 25 can also have an effective surface 24 concavely curved in the axial direction, but whose radius of curvature 7 is slightly larger than the convex curvature of the bearing point 1.
• the surface to be structured and also the active surface 24 of the tool 25 is not square as a rule, but larger in one direction of extent than in the other. In the example shown in FIGS. 5 a and c-with FIG. 5 c showing a plan view of the active surface 24-the larger direction of extent is the circumferential direction 28.
• a flushing groove 22 running in the direction of the greatest extension direction of the active surface 24 is preferably inserted into the active surface 24 End surfaces of the active surface 24 can end freely, but can also end before.
• the electrolyte 4 can distribute itself in the direction of the greatest extent with low flow resistance and from there flow away in the direction of the lesser extent, in this case the axial extent of the active surface 24, through the working gap 3.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
• Sliding-Contact Bearings (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

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• 2013
  • 2013-06-04 RU RU2014149142A patent/RU2014149142A/ru not_active Application Discontinuation
  • 2013-06-04 CN CN201380020875.1A patent/CN104813042A/zh active Pending
  • 2013-06-04 WO PCT/EP2013/061432 patent/WO2013182539A2/de active Application Filing
  • 2013-06-04 EP EP13726787.8A patent/EP2855952A2/de not_active Withdrawn
  • 2013-06-04 US US14/405,629 patent/US9879726B2/en not_active Expired - Fee Related
  • 2013-06-04 KR KR1020147031555A patent/KR20150018785A/ko not_active Application Discontinuation
  • 2013-06-04 JP JP2015514540A patent/JP2015525323A/ja active Pending
  • 2013-06-04 MX MX2014012354A patent/MX2014012354A/es unknown

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