Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B33/00—Honing machines or devices; Accessories therefor
  • B24B33/02—Honing machines or devices; Accessories therefor designed for working internal surfaces of revolution, e.g. of cylindrical or conical shapes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B33/00—Honing machines or devices; Accessories therefor
  • B24B33/08—Honing tools
  • B24B33/088—Honing tools for holes having a shape other than cylindrical

Definitions

• the invention relates to a honing process for machining the inner surface of a bore in a workpiece by means of at least one honing operation according to the preamble of claim 1 and a honing tool usable in carrying out the honing process according to the preamble of claim 6.
• a preferred field of application is the honing of cylindrical surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating engines.
• cylinder surfaces in cylinder blocks (cylinder crankcase) or cylinder liners of internal combustion engines or other reciprocating engines are exposed in operation a strong tribological stress. Therefore, it is important in the manufacture of cylinder blocks or cylinder liners to machine these cylinder liners so that adequate lubrication is ensured by a lubricant film later under all operating conditions and the frictional resistance between relatively moving parts is minimized is held.
• Honing is a machining process with geometrically indeterminate cutting edges.
• an expandable honing tool is moved within the bore to be machined to generate a stroke amount in the axial direction of the bore at a stroke frequency up and down, and at the same time rotated at a revolution frequency to generate a rotational motion superimposed on the stroke motion.
• the mounted on the honing tool cutting material are pressed by a delivery system with a force acting radially to the tool axis feed force to the inner surface to be machined.
• a cross-cut pattern typical for honing is produced on the inner surface with intersecting machining marks, which are also referred to as "honing marks".
• the friction component of the piston group can be up to 35%, so that the reduction in friction in this area is desirable.
• Different approaches are used to reduce the mechanical losses of a motor.
• A. The use of thermally sprayed cylinder surfaces, the use of coated piston rings, the development of particularly optimized honing surfaces, etc.
• a technology that is becoming more and more important for reducing friction and wear is the avoidance or reduction of cylinder distortions Deformations of the engine block (cylinder crankcase) during assembly and / or operation.
• a Zyl inderbohrung typically have a bore shape, the least possible, z. B. a maximum of a few microns, deviates from an ideal circular cylinder shape.
• significant shape errors can occur, which can be up to several hundredths of a millimeter and reduce the performance of the engine.
• the causes of distortions or deformations are different. They may be static or quasi-static thermal and / or mechanical loads or dynamic loads.
• the construction and design of cylinder blocks also influence the tendency to deform.
• the sealing function of the piston ring package is typically degraded by such hard-to-control deformations, which can increase blow-by, oil consumption, and also friction.
• shaping honing Another technology which is intended to ensure or approximate the formation of an ideal shape after assembly or in the operating state of the engine by an inversion of the cylinder distortions (generation of a negative shape of the defect) is the so-called shaping honing.
• This is the unstrained workpiece
• a bore shape deviating from the circular cylindrical shape is produced, for example a cloverleaf shape.
• Such bore shapes are usually asymmetrical, because the deformations of the cylinder block are usually not symmetrical.
• an ideal circular cylinder shape should be provided so that the piston ring package can cover well over the entire bore.
• Various variants of the mold honing are described, for example, in EP 1 790 435 B1 and in the state of the art mentioned therein.
• the invention provides a honing method having the features of claim 1. Furthermore, a honing tool with the features of claim 6 is provided, which can be used in the context of the honing process.
• a bottle-shaped bore i. H . a hole m with a bottle shape generated.
• a "bottle-shaped bore" immediately following a bore entry has a first bore portion of a first diameter remote from the bore entry, a second bore portion of a second diameter greater than the first diameter, and a transitional clearance between the first and second bore portions
• the first bore portion and the second bore portion are generally circular cylindrical in shape and coaxial with one another
• the transition portion may be partially tapered and m each at its ends facing the outer bore portions It should be used to overgrow the radii in the adjacent drill holes.
• Bohru ng As part of the honing process, which leads to a bottle-shaped Bohru ng with optimal surface texture used in at least one honing a particularly suitable for this purpose honing tool, which is referred to here as "ring tool" due to its construction
• Anmdu ng has at least one annular Schneidgru ppe m it with three or more distributed around the circumference of the tool body of the honing tool, radially deliverable cutting bodies, which are designed as in the circumferential direction of the honing tool relatively wide and in the axial direction of the honing tool relatively narrow Honsegmente.
• the measured in the axial direction of the honing tool axial length of Honseg- elements is smaller than the measured width in the circumferential direction and the axial length of the body with cutting material equipped cutting area is smaller than the effective outer diameter of the honing tool. If at least three honing segments are provided, the machining forces can be distributed well and relatively evenly over the circumference over the entire effective outer diameter range of the honing tool available through radial infeed. It can Kings z. B. in a cutting group exactly three, exactly four, exactly five or exactly six Honsegmente same or different U mfangsbreite be provided. More than six honing segments within a cutting group are possible, but make the construction more complicated and are usually not required. In some cases it may be sufficient if the honing tool has only two honing segments.
• the axial length of the segments may be e.g. be less than 30% of the effective outer diameter of the honing tool, in particular between 1 0% and 20% of this outer diameter.
• the axial length may e.g. in the range of 5 mm to 20 mm.
• the axial length is typically less than 10% of this burn length. If the upper limits are clearly exceeded, the possibility of axial contour tracing or contour generation usually suffers.
• small axial lengths are advantageous to produce sufficient surface pressure for machining.
• a minimum length in axial direction is advantageous for enabling a honing overflow for machining the bore ends and for limiting a tilting tendency of the honing tool.
• Such a ring tool represents a departure from conventional concepts of honing tool design, which assume that to achieve less Form errors a honed bore honing tools should be used in the axial direction relatively long, in the circumferential direction, however, relatively narrow honing stones.
• An annular tool is particularly well adapted to the machining of bottle-shaped bore shapes or in general of bore shapes with a bore diameter that varies significantly in the axial direction.
• the cutting material bonded cutting grains of suitable granularity, density and hardness
• is concentrated in an axially relatively narrow ring typically occupying more than half of the circumference of an annular cutting group with cutting means, and thus effectively contributing to material removal ,
• the cutting area in which one or more annular cutting groups are compared to the effective outer diameter of the honing tool in the axial direction is short or narrow, whereby the generation and / or tracking of an axially extending contour is possible.
• annular sheath is characterized by the fact that in the axial section covered by the annular cutting group, substantially more contact surface exists between the cutting body and the bore inner surface than in a comparatively narrow axial section of a conventional honing tool.
• more than 60% of the circumference of an annular cutting group is occupied by cutting means, possibly even more than 70% or more than 80% of the circumference of the honing tool.
• a cutting group is arranged body in the vicinity of a spindle end facing away from the tool, that the cutting group ausschliessl I is located in the spindle facing away from the body of the tool. If several annular cutting groups are provided, this condition can apply to all cutting groups. An arrangement close to the distal end of the spindle allows, inter alia. Bearings with very low honing overflow.
• the stroke position of the honing tool can be used within the bore as a guide to give m high local resolution the contact pressure or the delivery force as a function of the stroke position of the annular cutting group. This makes it possible, with the aid of a deliverable annular cutting group, to produce a bore with an axially variable contour or to follow an axially previously generated contour without undesired pressure force peaks.
• a ring tool can be used in all axial areas The bore can be worked with substantially the same coverage, so that if necessary very uniform roughness images or surface structures Kgs be generated NEN.
• One or more sensors of a diameter measuring system can be arranged on the honing tool so that an in-process diameter measurement is possible. For example, between adjacent honing segments on the tool body, measuring nozzles of a pneumatic diameter measuring system may each be attached. As a result, the precision of the achievable bore contours can be improved.
• annular tool ensures uniform wear of the cutting material body and very good form values as well as uniform surface roughness of the bore over the entire service life of the annular cutting group.
• the ring tool has a single annular cutting group, whose honing segments are radially delivered or retracted via a single common delivery system.
• the annular cutting group has three or more uniform or irregular hovering members distributed over the circumference of the honing tool, usually not more than six.
• the single annular Sch enid mich is arranged in the vicinity of the spindle-facing free end of the tool body, for example, flush with the spindle-facing end face.
• Such constructions are particularly well suited for the machining of cylinder bores with reduced honing overflow.
• Such restrictions on processing arise, for example, blind holes or Zylinderbohru lengths in engine blocks for monobloc or V-engines.
• annular Schididgru ppe has two u nab rehabilitationll deliverable groups of Honsegmenten, wherein the Honsegmente of the groups are alternately angeord net in the circumferential direction.
• a single annular cutting group for example, especially in the machining of bores with a short honing overflow
• the advantages of double delivery of two independent groups of honing segments With such a tool, two consecutive honing operations with different cutting materials without intermediate tool change can be performed.
• the honing segments of a group of honing segments usually have the same cutting deposit, while the groups have different cutting plaques, for example diamond plaques of different grain sizes.
• a ring tool has a first annular Sch nedrios and at least one second annular Sch enidrios axially offset from the first annular cutting group and can be delivered independently of the first annular cutting group.
• This also makes two consecutive honing operations with different cutting materials without intermediate tool change possible. Since the different cutting materials on the at least two axially offset from each other annular Schneidgru ppen are distributed, each of which cover a large part of the circumference of the honing tool NEN, particularly high Abtragsnch or relatively short Hon times are possible here in both honing operations.
• Such ring tools Kings nen be used for all holes that allow enough Honüberlauf.
• Such a ring tool preferably has exactly two annular cutting groups, whereby a flexible use is possible despite a simple structure.
• an integrated, multi-axis movable joint for example a ball joint or a cardan joint
• a ball joint or a cardan joint is provided on the tool body. So nen position errors of the machine and / or a core offset of the bore can be compensated without changing the bore position.
• Embodiments without joint are also possible.
• the bottle shape of the bore can be produced by any suitable machining process, for example by fine turning (fine spindles), ie by means of a degreesu ngshabilits with geometrically defined cutting edge, or by honing. This can be followed by one or more honing operations to arrive at the final desired hole geometry with a suitable surface structure.
• a bore with circular-cylindrical bore shape is first produced by fine turning or honing, and then a bottle-shaped bore shape is produced in a bottle honing operation by honing with axially varying honing removal.
• honing makes it possible to produce surfaces with particularly uniform surface quality without circulating tracks.
• the self-sharpening effect of the cutting material body also contributes to the uniformity of the surface quality.
• an expandable honing tool with at least one ring-shaped shelling group is used in the bottle honing operation, ie an annular tool. Honsegmente the cutting group in a downstroke according to the bottle shape depending on stroke position, away and / or force controlled delivered radially outward and retracted radially in an upstroke according to the bottle shape in response to the stroke position.
• the transition section which is particularly difficult to process, results from the outset in a relatively smooth contour progression.
• the bottle honing operation it is also possible for the bottle honing operation to use an expandable honing tool with honing stones whose length is more than 50% of the length of the bore.
• the length of the honing stones can for example be between 50% and 80% of the length of the bore.
• the honing tool is then moved in a first stroke position between an upper and a lower Um Kunststofftician up and down or back and forth in order to bring the first hole along its entire length in a circular cylindrical shape. Thereafter, in a second phase, the upper reversal point is incrementally, i.e.. over several strokes, changed in the direction of the lower Um Kunststoffhuis, so that the stroke length is gradually reduced.
• a smooth honing operation is preferably carried out after the bottle honing operation for smoothing the bore profile in the transitional region, wherein an annular tool is used in the smoothing honing operation, ie an expandable honing tool with at least one annular cutting group , With the aid of the ring tool, grooves or burrs in the transition section can be eliminated and the radii of the transition section rounded off.
• the invention also relates to a honing tool which is particularly suitable for carrying out the honing process, but can also be used in other honing methods not according to the invention.
• the invention also relates to a workpiece having at least one bore having a honed inner surface, wherein the Bohru ng is a bottle-shaped bore, ie the following at a hole entrance a first Bohru ngsabsch nitt with a first diameter, away from the bore entry a second bore portion having a second diameter greater than the first diameter, and having a transition portion between the first and second bore portions with a continuous transition from the first diameter to the second diameter; when the workpiece has been machined using a honing tool according to the invention.
• the Bohru ng is a bottle-shaped bore, ie the following at a hole entrance a first Bohru ngsabsch nitt with a first diameter, away from the bore entry a second bore portion having a second diameter greater than the first diameter, and having a transition portion between the first and second bore portions with a continuous transition from the first diameter to the second diameter; when the workpiece has been machined using a hon
• the workpiece may be a cylinder block or a cylinder liner for a reciprocating engine.
• the workpiece may be z.
• B. u m an internal combustion engine (Verbrennu ngsmotor) or act on a compressor.
• Fig. 1 shows a schematic longitudinal section through a bottle-shaped cylinder bore in an engine block
• FIG. 2 shows in FIG. 2A a longitudinal section through an embodiment of a ring tool with simple widening of a single annular cutting group and in FIG. 2B a cross section through the cutting group;
• FIG. 3 shows in FIG. 3A a longitudinal section through an embodiment of an annular tool with double widening of a single annular cutting group and in FIG. 3B a cross section through the cutting group;
• FIG. 4 shows in FIG. 4A a longitudinal section through an embodiment of a double expansion ring tool in the case of two annular cutting groups arranged one above another, and in FIG. 4B a cross section through one of the cutting groups;
• FIG. Figure 5 shows schematically a longitudinal section through a bore machined by means of a honing tool with relatively long honing stones
• Fig. Figure 6 shows schematically the stroke position of a honing tool with long honing stones as a function of the honing time t in the bottle honing operation.
• Fig. 7 shows a measurement diagram of a rounded profile of a bottle-shaped cylinder after the use of an annular tool.
• Fig. 8 is a schematic diagram showing the dependence of the stroke position HP (solid line) and the expanding position AP (broken line) as a function of the honing time t in a second embodiment.
• Fig. 1 shows a schematic longitudinal section through such a bottle-shaped bore 1100 in a workpiece 100 in the form of an engine block (cylinder crankcase) for an internal combustion engine
• the bore is rotationally symmetrical with respect to its bore axis 1 1 2 and extends over a bore length L from a bore entry 1 14 facing the cylinder head in the installed state to the opposite end at the bore exit 1 1.
• the bore can be subdivided into three adjoining sections of different function, which are sliding, that is to say without the formation of steps or edges , merge .
• a first bore section 11 at the inlet end has a first diameter D1 and a first length L1.
• a partially conical transition section 140 Between the first bore section 1 20 and the second bore section 1 30 there is a partially conical transition section 140, in which a continuous transition from the first diameter to the second diameter takes place.
• a first radius R1 is formed, while a second radius R2 is formed between the transition section and the second bore section.
• the radii R1 and R2 may be substantially the same, but it is also possible that the first radius is smaller or larger than the second radius.
• the first length L1 may be between 1 5% and 40% of the bore length L.
• the second length L2 is typically greater than the first length and often lies between 40% and 60% of the length of the drill hole L.
• the transition section is normally relatively short compared to the adjacent bore sections.
• Typical third lengths L3 can be in the range of 5% to 20% of the bore length L are. Deviations from these geometrical conditions are possible.
• the difference in diameter between the first diameter D1 and the second diameter D2 is well outside the tolerances typical for the honing, which are for a cylindrical shape in the order of a maximum of 1 0 ⁇ (based on the diameter).
• the diameter difference can be, for example, between 20 ⁇ m and 90 ⁇ m.
• the radii R1, R2, the lengths of the outer bore portions and the transition portion, and the tangent angle T between the bore axis and a tangent to the transition projection may be optimized to provide low blow-by, low oil consumption in typical engine operating conditions and low wear of the piston rings.
• the bottle shape of the bore causes the bore in the region near the inlet is comparatively narrow, so that the piston rings of the running in the bore piston are pressed under high hoop stress to the bore inner surface 1 1 8.
• the piston accelerated by the combustion then moves in the direction of the bore exit, with the piston rings initially passing (partially) through the transition section with the continuously enlarged inner diameter and then the second bore section. In the transition section, the piston rings can relax all gradually, the seal remains sufficient, because the pressure difference decreases at the piston rings.
• the ring package At the beginning of the second bore section, the ring package reaches its lowest tension, so that friction losses are reduced by reduced ring tension, especially in the region of maximum piston speed.
• the hoop tension then increases again as soon as the piston rings reach the exit-side radius of the transition section and pass through it in the direction of the first bore section.
• a finishing process which can economically produce such a bore both in terms of macro shape (bottle shape) and in terms of the surface structure of the tribologically stressed Bohrungsin nenthesis in high quality comprises in embodiments of the invention at least one honing operation, in which A ring tool has at least one ring on the tool body attached cutting group with distributed around the circumference of the tool body cutting bodies by means of a zugeord Neten to-Stellsystems in Radialrichtu
• the cutting-material bodies are designed as honing segments whose width in the circumferential direction is significantly greater than their length in the axial direction.
• the cutting-material bodies responsible for the material removal on the workpiece are in an axially relatively narrow zone (a ring) the cutting group) concentrates and occupies a relatively large portion of the circumference of the honing tool, thereby enabling bore shapes with relatively high material removal rates to be bored, in which bore portions of different diameters adjoin one another in the axial direction en.
• FIG. 2 shows in FIG. 2A a longitudinal section through an embodiment of a ring tool 200 with a single annular cutting group 220 and simple widening.
• FIG. 2B shows a cross section through the cutting group.
• the ring tool 200 has a tool body 21 0, which defines a tool axis 21 2, which is simultaneously the axis of rotation of the ring tool during the honing operation.
• a tool body 21 0 which defines a tool axis 21 2 2
• the spindle-side end of the ring tool at the spindle-side end of the ring tool (in Fig.
• annular cutting group 220 is the annular cutting group 220, the plurality (in the example, three) uniformly over the circumference of the tool body distributed cutting material body 220-1, 220-2, 220- 3, Which can be delivered by means of a cutting material body feed system radially to the tool axis 21 2 outwards NEN to press the abrasive outside of the outside Shen of the cutting material body with a defined pressing force or contact force against the inner surface of a bore to be machined.
• Each of the three arcuately curved cutting material bodies is designed as a very wide in the circumferential direction, in contrast, in the axial direction narrow Honsegment which covers a Ufangswin- angle range between 1 1 5 ° and 1 20 °.
• the honing segments are decoupled from the tool body and can be displaced radially relative to the tool axis 21 2.
• the ring formed by the honing segments terminates flush with the tool body on the side facing away from the spindle, so that the ring is completely within the spine. delabgewandten half of the tool body sitting at the end facing away from the spindle of the ring tool.
• the axial length LHS of the heel segments is less than 1 5%, in particular less than 10% of the bore length L.
• the honing segments are approximately 4 mm to 35 mm, in particular approximately 10 mm high (in the axial direction), which in the example corresponds to between 5% and 30%, in particular between 10% and 20% of the effective outside diameter of the cutting group.
• the axial length LHS simultaneously corresponds to the axial length of the entire cutting region of the honing tool.
• Each kidney material body is fixed to an outside of an associated support bar 224-1, 224-2 made of steel by soldering. Alternatively, the cutting material body can also be attached by gluing or by screws, whereby an easier replacement is possible me.
• Each support strip has on its inner side an inclined surface, ie, the cooperates with a conical outer surface of an axially displaceable feed cone 232 in such a way that the support strips are delivered with the cutting material carried by them radially outward, who n the Zustellkonus means of a machine-side Zustellvorrichtu ng is pressed against the force of return springs 234, 226, 228 in the direction of the spindle end facing away from the ring tool.
• FIG. 3A shows a longitudinal section through the ring tool
• FIG. 3B is a cross section through the cutting group.
• the annular cutting group 320 has two independently deliverable groups of honing segments, wherein the honing segments of the groups are each arranged in the circumferential direction alternately to each other are .
• a first group of Honseg instruments has three by 1 20 ° circumferentially offset from each other arranged first hearing segments 320-1. In each case there are arranged three second hearing segments 320-2 of a second group of hearing segments.
• the first group has cutting material body with a relatively coarse cutting surface, while the second group has cutting material body with a relatively finer cutting surface.
• a ball joint 350 is provided between the tool body 31 0 and the coupling structure 340 provided for coupling the honing tool to a work spindle or the like, so that the honing tool is limitedly movable in several axes with respect to the honing spindle.
• the first hours can be radially delivered with the help of a first delivery system.
• a first delivery system To this belongs a centrally on the tool body extending first feed rod 332-I, which has a conical portion at the end facing away from the spindle, which cooperates with the inclined surfaces of support strips of the first group of Honsegmenten.
• a second infeed system serves to deliver the second group of segments and has a tubular delivery element 332-A which surrounds the infeed rod 332-I and has at its end facing away from the spindle a conical outer surface which has inclined surfaces on the support strips of the second Honsegmente interacts.
• the first delivery system of the first group of response segments can be expanded with the aid of the first delivery system in order to carry out a specific honoring operation, for example a smooth honing operation or a structure honing operation.
• a specific honoring operation for example a smooth honing operation or a structure honing operation.
• another honing operation such as a de-grating operation or a plateau honing operation may be performed.
• two different honing operations can be performed one after the other, without having to change tools or use another honing spindle for machining.
• FIG. 4 shows in FIG. 4A a schematic longitudinal section through an embodiment of a ring tool 400 with double widening, which, unlike the exemplary embodiment of FIG. 3 has two annular cutting groups 420-1 and 420-2, d he axially offset from each other in the spindle-facing part of the tool body 41 0 are attached.
• Each of the annular cutting group (cross section in Fig. 4B) has three common deliverable Honsegmente, each between about 1 1 0 ° and 1 1 5 ° of Cover the circumference.
• the axial length of the Honsegmente is in contrast small and is typically less than 1 0% of the bore length and / or between 1 0% and 20% of the effective outer diameter of the honing tool in the cutting material body.
• measuring nozzles 440 of a pneumatic diameter measuring system are mounted on the tool body.
• the cutting groups are axially close to each other, so that the cutting region of the honing tool, in which the two annular cutting groups lie, in the axial direction is substantially shorter than the effective outer diameter of the honing tool.
• the cutting material body are elastically yielded with respect to the tool body. This can possibly improve the ability to trace the contour during axial movement.
• spring elements eg., Leaf springs, coil springs of the like
• the support elements resiliently yielding, e.g. B. by weakening of the substrate cross-section in the form of slots or the like are provided constructively at appro priate points.
• a conventional honing tool with axially relatively long, narrow honing stones was used to produce a honed bore with a circular cylindrical shape, starting from a pre-machined hole, for example by fine boring.
• the axial strip length I was about 1/2 to 2/3 of the total hole length L.
• a first honing operation pre-honing
• a subsequent arhonoperation was carried out with fine grain (Grainng D54).
• a substantially circular-cylindrical bore shape with little deviation from the ideal shape and with a relatively smooth surface (R z ⁇ 8 ⁇ m) was produced.
• the inlet-side and outlet-side honing overflow s was approximately 1/3 of the strip length, similar to conventional methods.
• the honing overflow can be shortened when machining V or monoblock motors.
• a subsequent third honing operation was designed as a bottle honing operation.
• a bottle honing operation By means of a bottle honing operation, a bottle-shaped bore shape is produced by axially varying material removal with geometrically indefinite cutting.
• Figure 6 shows schematically the stroke position HP of the honing tool as a function of the honing time t in the bottle honing operation.
• the machining of the cylinder running surface initially proceeds from a first point of time t 1 to a second time point t 2 with the same stroke length in a first stroke position as during machining of a circular cylindrical bore.
• the term "stroke position" refers to the region between the upper reversal point UO and the lower reversal point UU of a reciprocating movement Each displacement of a reversal point thus also changes the stroke position.
• the honing machine switches automatically to an incremental change of the stroke position and after each stroke, the upper Um Kunststoffpu is point UO changed incrementally in the direction of the lower Um Kunststoffticians UU.
• the temporal position of the second time instant t 2 can be defined for example via a specific number of strokes or over a predetermined honing time or via a predetermined material removal or another triggering parameter.
• the amount of increment IN that the upper control point varies between two consecutive strokes can also be adjusted as needed.
• the bottle honing operation is advantageously carried out with honing stones whose cutting material grains are finer than those in the pre-honing or intermediate honing. For example, it is possible to work with diamond grains in the region D35 in order to obtain a bottle shape with already a relatively fine surface structure.
• a relatively rough surface structure with small steps similar to a saw profile can result in the transition region. Such structures are generally undesirable.
• a rounding of the radii and a smoothing of the surface is thus carried out with the aid of a ring-work nose in the method described here after the bottle honing operation.
• n for example in the range D1 0 to D1 5, in particular D1 2.
• the selection of a suitable ring tool depends inter alia on the design of the cylinder block.
• the tool selection can be oriented, for example, to the extent of the possible honing runs and / or the position and size of transverse bores. If, for example, a cylinder crankcase has a large transverse bore, it usually makes sense to work with a single widening ring tool (cf., for example, FIG. 2).
• a single widening ring tool cf., for example, FIG. 2.
• such an annular tool has been employed with an annular cutting assembly to smooth out grooves or burrs that have arisen during processing of the bottle honing operation in the transfer tail.
• the radii of the transition region can also be rounded and the surface values can be changed so that they are substantially identical to the surface values in the adjacent first and third bore sections.
• Fig. 7 shows a measurement diagram of a rounded profile of a bottle-shaped cylinder after the use of a single expansion ring tool in the process shown here.
• the scale in the x-axis of the diagram (parallel to the bore axis) is 5 m per unit of measure shown, in the y-axis (in the radial direction of the bore) a unit of measure is 1 0 ⁇ .
• annular tool brings here not only advantages in view of the smooth, edge-free course of the bore contour in the axial direction. Since in ring tools of the type described here, the cutting material body of an annular cutting group a large part of the U mfangs the honing tool (for example, between 70% and 80%) einneh men, erg ibt is also honing a very uniform coverage of the machined bore inner surface in all axial Positions.
• the term "coverage” refers qualitatively to the uniformity of the distribution of honing marks over the entire bore length and circumference.
• conventional honing tools with axially relatively long honing stones are used, an uneven roughness or waviness may be present in them Depending on the design of the block, this problem can be exacerbated when, for example, engine blocks have to be machined with shorter honing runs.
• a honing discharge of only a few millimeters in length can result in uneven wear of the long honing stones
• the problem is that when using conventional honing tools (with long honing stones) such problems can be largely avoided by choosing suitable honing parameters, but the design of the corresponding honing process is relatively time-consuming and cost-effective It is often necessary to carry out several tests until a honing process design has been optimized in such a way that uneven processing with long strips is avoided.
• an annular tool many of the conventionally occurring problems can be avoided.
• the advantages of ring tools include:
• Ring-shaped cutting groups wear substantially uniformly, so that unwanted Konizticianen especially in the range of the lower Umticians at
• the advantages of ring tools are retained and the required number of strokes for uniform struc- ture of the inner bore surface will still be lower than the corresponding stroke rate when using a conventional honing tool with long honing stones.
• the delivery force can be expediently exerted by means of a hydraulic widening, so that the surface can be machined essentially with constant force.
• the tracking of the contour which varies in the axial direction can then be adjusted solely by the flexibility of the hydraulic widening due to the design.
• one or more further honing operations can be followed in order to produce the final desired surface structure on the bottle-shaped bore.
• a fifth honing operation which is referred to here as "spiral structure honing with ring tool" follows in this honing operation, the axial speeds and the rotational speed of the honing tool being matched to one another such that relatively large honing angles, Of course, other honing angles and / or roughness profiles can also be produced in other variants of the method.
• spiral pattern honing is designed in such a way that practically no more global material removal is achieved but I am to be produced in the after smoothing very smooth surface with the help of a relatively coarse cutting material body with low cutting grain density grooves of suitable depth and distribution.
• cutting material body with cutting center grain density 1, 25 to 1 5 vol.% and / or Grain size 35 to 200 ⁇ be used (see. e.g. DE 1 0 2005 01 8 277 A1).
• a ring tool with fine cutting means n is preferably also used, for example the same ring Tool, which was also used for the fourth honing operation (rounding of radii and smooththons).
• the expansion can be hydraulically / hydraulically, hydraulically / mechanically or mechanically / mechanically designed. In a mechanical expansion see z. B. force controlled by a servo-mechanical expansion (hydraul ic-like) or position and force controlled.
• an expandable ring tool is used in the bottle honing operation, that is to say when producing a bottle-shaped bore form from a previously still circular-cylindrical bore form.
• the control of the expansion system for the radial delivery of Honsegmente is coupled to the control for the stroke position, so that the ring tool can generate the Studentsgangsabsch nitt with the changing diameter accurately and in the cylindrical first and second Bohrungsabschn it with appro priate Pressing force works (see Fig. 8).
• the bottle honing operation may be provided as a second honing operation immediately after prehone, and so far replace the second to fourth honing operations of the first embodiment.
• Fig. 8 shows by way of example a schematic diagram which shows the dependence of the axial stroke position HP (solid line) and the radial widening position AP (dashed line) as a function of the honing time t during bottle honing with ring tool.
• Ring tools of the type described here can not only be used for the production or processing of bottle-shaped holes, but Kings nen also bring significant benefits without modification when machining holes with different geometry.
• a double widening ring tool with a single cutting group ring identical or similar to the embodiment of FIG. 3 to use to create a freeform with a non-circular bore cross section at a hole. This is commonly referred to as form honing.
• a bore portion with cloverleaf or Ell ipsenform the Quersch nitts are generated.
• the honing machine must have the ability to control the first delivery system and the second delivery system at the same time, depending on the stroke position and angular position of the cutting group to the bore expansions must be controlled with different force / position, so that the freeform can arise.
• annular tool to create and / or machine a bore shape that has a frusto-conical bore portion (cone neck) that transitions relatively abruptly or with transition radius into an adjacent cylindrical bore portion without collapsing another hole section connects.
• a bore of funnel shape having an input cylindrical first bore portion having a first diameter that increases in an adjacent second bore portion to the bore bottom conically up to a maximum diameter.
• the diameter difference between the cylindrical first bore portion and the maximum diameter in the conical second bore recess may be e.g. between approx. 20 ⁇ and about 90 ⁇ lie.
• the axial length of the cylindrical first bore portion may be e.g. between 20% and 80% of the total Bohru ngsplain.
• a ring tool in a bore a barrel-shaped bore section, d. H . to create a bulge in an otherwise largely cylindrical bore.
• the bulge may be approximately in the middle or close to one of the drill holes.
• strip honing When an annular tool is used, it is also relatively inexpensive to machine a cylinder surface such that there are narrow strips with different surface structures in the area of the upper dead center and / or in the area of bottom dead center than in the middle region of the highest piston speed.
• This variant is referred to herein as "strip honing.”
• a conventional method suitable for this purpose and a correspondingly adapted honing tool are described, for example, in DE 1 95 42 892 C2, in which, in addition to a honing operation, the entire axial Length of the honing tool processed with long honing stones, a short-stroke honing carried out with the help of short honing stones, this Honbearbeitung covers only the area of top dead center and the u nteren dead center.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Geometry (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)
• Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)

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• 2013
  • 2013-03-18 DE DE102013204714.2A patent/DE102013204714B4/de active Active
• 2014
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