EP3582931B1 - Honing tool and fine machining method using the honing tool - Google Patents

Description

FIELD OF APPLICATION AND PRIOR ART

The invention relates to a honing tool according to the preamble of claim 1 and a fine machining method according to the preamble of claim 10.

A preferred area of application is the finishing of cylinder running surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating engines.

The cylinder running surfaces in cylinder blocks (cylinder crankcases) or cylinder liners of internal combustion engines or other reciprocating machines are exposed to strong tribological stress during operation. Therefore, when manufacturing cylinder blocks or cylinder liners, it is important to machine these cylinder running surfaces in such a way that later, under all operating conditions, sufficient lubrication is ensured by a film of lubricant and the frictional resistance between parts that move relative to one another is kept as low as possible.

The quality-determining final machining of such tribologically stressable inner surfaces is usually carried out with suitable honing processes, which typically include several consecutive honing operations. Honing is a machining process with geometrically undefined cutting edges. In a honing operation, an expandable honing tool is moved up and down or back and forth within the bore to be machined at a stroke frequency to generate a stroke movement in the axial direction of the bore and at the same time rotated at a rotational frequency to generate a rotary movement superimposed on the stroke movement. The cutting material bodies attached to the honing tool are pressed against the inner surface to be machined via a cutting material body infeed system with an infeed force acting radially to the tool axis. During honing, a typical cross-hatch pattern for honing occurs on the inner surface with crossing traces of processing, which are also referred to as "honing marks".

To prepare the workpieces to be machined for honing, pre-machining by fine boring, sometimes also referred to as fine turning or fine boring, can be carried out beforehand. Fine boring operations, which are carried out with fine boring tools with a geometrically defined cutting edge, are generally used to determine the desired position and angular position of the bore, and if necessary also to produce bore shapes that deviate from a circular-cylindrical shape. An essential task of the honing operation with a lower oversize compared to fine boring is the creation of the required surface structure.

With increasing demands on the economy and environmental friendliness of engines, the optimization of the tribological system of pistons/piston rings/cylinder running surface is of particular importance in order to achieve low friction, low wear and low oil consumption. The macroscopic shape (macro shape) of the bores and the surface structure are of particular importance.

In some fine machining processes, a bore shape deviating from the circular cylinder shape is produced by means of fine boring and/or honing. Borehole shapes of this type are generally asymmetrical in the axial direction and/or in the circumferential direction, because the deformations of the cylinder block are also generally not symmetrical. In the operating state, the most ideal possible circular cylinder shape should result, so that the piston ring pack can seal well over the entire circumference of the bore.

Different types of honing tools have been developed due to a wide variety of requirements. First of all, they can be divided into honing tools that can be advanced during processing and honing tools that can be preset. Honing tools that can be infed during processing can be further subdivided into ledge honing tools, such as single ledge honing tools, multiple ledge honing tools and special tools, and largely full-surface tools, such as shell tools and shank tools. The so-called mandrel tools or Precidor honing tools fall under the category of presettable honing tools.

Single-bar honing tools are often used when machining small, high-precision parts. Multi-blade honing tools are available for various applications in a wide variety of designs. High cutting rates can be achieved with honing due to the high cutting tool capacity and its application parameters.

In the case of bores with large interruptions, the use of classic honing tools can lead to problems. Although the individually guided honing stones can ensure a concentric expansion and optimal roundness of the bore, there is a risk that they will catch in the workpiece if there are large interruptions. Among other things, the so-called shell tools were developed for these applications, in which cutting means are arranged on a cutting material body carrier that is relatively wide in the circumferential direction. A A shell tool can be constructed, for example, with only two cutting material body carriers (half shells), possibly also with three or four or more cutting material body carriers corresponding to a smaller circumferential width.

Shell tools can be designed with different construction.

The Publication DE 1652074 describes a honing tool with shell segments, which are produced in one piece as a sintered part with cutting coating and which can have a multiplicity of outwardly projecting ribs as carriers for the cutting coating.

The DE 102013204714 A1 is seen as the closest prior art for the independent claims and discloses, for example, honing tools designed as shell tools that are suitable for machining rotationally symmetrical bores that have bore sections of different diameters and/or shapes. For example, holes with a bottle shape, cone shape or barrel shape can be machined and/or created. The corresponding honing processes are sometimes referred to as "contour honing". The honing tool has an expandable annular cutting assembly having a plurality of cutting material bodies circumferentially distributed about the tool body, the axial length of which, measured in the axial direction, is less than an effective outer diameter of the cutting assembly when the cutting material bodies are fully retracted. The cutting group has a plurality of radially advanceable cutting material body carriers, each of which covers a circumferential angle range that is greater than the axial length of the cutting group.

Due to the relatively short axial length of the cutting group, such honing tools are particularly well suited for generating an axial contour and/or for following an already existing axial contour of the bore. In addition, small axial lengths of the cutting group can be advantageous in order to generate sufficient surface pressure for machining. The fact that the cutting group has several radially adjustable carriers of cutting material bodies, each of which covers a circumferential angle range that is greater than the axial length of the cutting group, means that, for example, transverse bores in the wall of a cylinder barrel can be bridged in the circumferential direction during honing , so that despite the axially short cutting material body, there is no risk of uneven machining in the area of cross bores. When using such honing tools, it is also possible to work with a very small honing overflow at the axial ends of a bore without problems with uneven cutting body wear occurring. However, it has been observed that in certain cases when machining non-cylindrical bores (e.g. bottle-shaped, cone-shaped or barrel-shaped bores), locally different surface structures occur due to different cutting depths can be generated. These can cause technical disadvantages. If the local roughness is too high, for example, oil consumption and blow-by can be increased. If too little material is removed locally, the risk of seizure during operation of an internal combustion engine can increase due to insufficient removal of material damage from upstream processing stages. Near the axial ends of a bore, the micrograph may deviate from the micrograph in the rest of the bore.

The patent application DE 10 2004 046 537 A1 describes a method of honing in which a bore is machined in a single honing operation using a pre-bored honing tool, producing a pre-bored hole. The pre-width honing tool is moved back and forth within the bore, essentially parallel to the longitudinal axis of the bore, and due to the design of the pre-width honing tool, a substantially uniform removal rate is generated over the axial length of the central section of the bore, while the removal rate outside of the central section of the bore is towards the ends of the bore increases. In one embodiment of a prewidth honing tool ( 7 ) an elastic area or an elastically flexible element is provided in a honing element between the honing stone carrier and the honing stone. The elastic area can be produced by an elastic plastic or rubber or by an elastic spring system made of metal or other elastic materials. The spring-loaded mounting allows a corresponding tilting of the honing stone to occur in the event of an axial unequal distribution of a radial pressure on the honing stone, in order to avoid excessively unequal distributions.

The EP 1 815 943 A1 describes methods for honing bores. Among other things, a honing process is described in which peaks of the roughness profile that are still present after a shaping honing process are to be removed. In this machining operation, which is essentially shape-neutral, the inner surface of the bore can be machined, for example, with a large number of relatively small, elastically mounted cutting material bodies that can be moved relative to one another. Such a strongly segmented plateau honing tool is able to machine the selected surface of a deliberately out-of-round bore with a cylindricity error of well over 10 µm to a large extent evenly.

The EP 1 932 620 A1 shows examples of double-flaring honing tools that have two cutting groups of honing sticks of different grain sizes that can be adjusted independently of one another and that are arranged alternately in the circumferential direction of the honing tool.

TASK AND SOLUTION

It is an object of the present invention to provide a generic honing tool and a fine machining method that can be carried out with it, which allow bores of different shapes to be machined in such a way that the machined bore surfaces have a well-defined surface structure over the entire length of the bore.

To solve this problem, the invention provides a honing tool with the features of claim 1 ready. Furthermore, a finishing method with the features of claim 10 is provided. Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated into the description by reference.

The expandable cutting group attached to the tool body has a plurality of radially feedable carriers of cutting material body, which each cover a circumferential angle range and can be fed radially to the tool axis by means of a cutting group feed system assigned to the cutting group. The circumferential angle range can be, for example, 30° or more, 40° or more, or about 60° or more, or even 90° or more. Each cutting material body carrier carries on its radial outside a plurality of narrow cutting material bodies which are arranged at a mutual lateral distance from one another and each cover only a fraction of the circumferential angle range. Spaces or gaps without cutting material thus remain between the cutting material bodies. As a result, reliable lubrication with cooling lubricant and sufficient removal of machining residues can be ensured even in the case of heavy material removal.

The cutting material bodies are designed as cutting material strips that are narrow in the circumferential direction, the width of which in the circumferential direction is small compared to the axial length of the cutting material strips. If necessary, cutting material strips can be used to achieve a particularly even coverage over the entire length of the bore, even at the ends of the bore where a honing overflow may be desired. An aspect ratio between the axial length and the width to be measured in the circumferential direction can be in the range from 4:1 to 20:1, for example.

The cutting material bodies can consist entirely of cutting means or have a carrier made of metal, for example, which carries the cutting means. The cutting means can have, for example, diamond or cubic boron nitride (CBN) cutting grains, which are bonded in a metallic or ceramic matrix.

The cutting group has cutting material bodies that are not applied directly or directly to the radial outside of the associated cutting material body carrier and are also not rigidly or firmly connected to it. Rather, it is provided that an elastically yielding intermediate layer is arranged in a space between a cutting material body and the cutting material body carrier carrying the cutting material body, which intermediate layer fills the space between the cutting material body and the cutting material body carrier.

There are honing tools that do not belong to the claimed invention, in which all cutting material body carriers or all cutting material bodies of the honing tool can be radially infed with a single common infeed. Such honing tools are referred to as single flare honing tools.

Honing tools according to the claimed invention are characterized in that the honing tool is designed as a double flare honing tool. In such honing tools, the cutting group comprises a first group of cutting material body carriers and a separate second group of cutting material body carriers, the first group and the second group being feedable independently of one another. When using a honing tool with a double expansion, fine machining processes are possible in which the cutting material body carriers of a group are radially advanced and retracted together. As a result, for example, one of the groups can be disengaged from the inner surface of the bore by retracting it, so that the inner surface of the bore is machined only by the other group. It is also possible to machine the inner surface of the bore simultaneously with all cutting material bodies of the first and second group.

The use of a honing tool with double expansion offers potential for shortening cycle times, since tool changes between successive different honing operations can be omitted. In some embodiments, an upstream first honing operation is first carried out with the first group, this first group is then withdrawn, the other group (second group) is preferably fed radially outwards at the same time as the first group is withdrawn, and then the cutting material bodies of the second Group carried out a downstream second honing operation.

Honing tools with double expansion according to the claimed invention are characterized in that in the first group the cutting material bodies are attached directly to the associated cutting material body carrier without the interposition of an elastic intermediate layer and are thus rigidly connected to the cutting material body carrier, while in the second Group the cutting material body are individually attached elastically flexible via an elastic flexible intermediate layer on the associated cutting material body carrier. With the double expansion it is possible, for example, to first use the first group in order to carry out a first honing operation which is designed as a contour honing operation in order to specifically change the axial contour of the bore starting from a previous machining operation. The first group can then be disengaged and the second group engaged with the inner surface of the bore in order to use the second group to carry out a second honing operation in the form of a follow-up honing operation, in which only slightly abrasive and elastically resilient cutting material bodies of the previously created contour are held in the Follow up essentially and primarily improve the surface structure.

The cutting material bodies of the first and the second group can have altogether different removal characteristics or other properties determined for the material removal. For example, the cutting material bodies of the two groups can have different widths and/or be attached with different circumferential distances and/or different divisions on the respective associated cutting material body carriers. Alternatively or additionally, it is also possible for the cutting material bodies of one of the groups to be equipped with a coarser grain for coarser machining and for the cutting material bodies of the other group to be equipped with a finer grain for finer machining. It is thus possible, for example, to carry out a pre-honing operation with substantial material removal and a subsequent finish honing operation with little or almost no material removal, mainly for smoothing the previously structured surface, one after the other with the same honing tool.

In the case of honing tools according to the claimed invention, it is therefore provided that only part of the cutting material bodies of a cutting group is carried by such an intermediate layer and another part is rigidly connected to the cutting material body carrying it. All cutting material bodies of a cutting material body carrier are either flexibly connected to the associated cutting material body carrier via an elastic intermediate layer or all are rigidly attached to it, so that there is no mixture of rigidly and flexibly coupled cutting material bodies on a cutting material body carrier.

Each cutting material body carrier thus carries a cutting material body group with two, three, four, five, six, seven, eight or more relatively narrow cutting material bodies, between which gaps remain in the circumferential direction. The cutting material body group (group of cutting material bodies) is carried by the essentially rigid cutting material body carrier, so that all cutting material bodies of the cutting material body group are radially infed together when the cutting material body carrier is radially infed. The requirement according to the radial feedability of the carrier of the cutting material body, the carrier must be movably mounted in relation to the workpiece body, mobility in the radial direction being necessary above all. However, a certain tilting of a cutting material carrier cannot be completely ruled out, for example in the area of the honing overflow, since there, viewed in the axial direction, the cutting material body and thus the associated cutting material carrier are loaded unequally.

Due to the elastically flexible intermediate layers between the cutting material bodies and the cutting material body carrier carrying them, there is a certain degree of individual flexibility or mobility of the cutting material bodies in relation to the (rigid) cutting material body carrier carrying them and in relation to other cutting material bodies of the cutting material body group. It has been shown that in this way the adaptability of the honing tool or the cutting material body to different orientations of the surface to be machined can be further improved compared to conventional solutions.

Improvements can result in particular in the case of cone shapes and/or in the area of axial transitions between cylindrical and conical bore sections and/or in the area of axial transitions between sections of different cone angles. Furthermore, the cutting material bodies can also better follow any deviations from the roundness of the bore in the case of oval bore shapes or roundness deviations of a higher order. If necessary, improvements can also result in the area of the reversal point of the axially reciprocating honing movement, i.e. there where a tilting moment can occur on the arrangement of cutting material bodies and the supporting cutting material body carrier when changing direction.

Among other things, the intermediate layer allows a cutting material body to remain oriented largely parallel to the machined bore surface despite any tilting moment that may affect the overall arrangement (cutting material body carrier with cutting material bodies), resulting in a well-definable, uniform surface structure even in axial transition areas with different surface orientations and up to the axial bore ends can be ensured. Because the intermediate layer fills the space between the cutting material body and the cutting material body carrier, no abrasion can occur between the cutting material body and the cutting material body carrier, so that the individual flexibility is retained throughout the entire honing process, even with heavy material removal. Also so that the surface damage caused by scratches and / or grooves can be prevented, which by Accumulation of abrasion and/or coarse cutting grains or foreign bodies can occur in the recesses of spring-loaded slat supports.

Honing tools according to the invention are particularly suitable for honing bores with an axial contour. The individually flexibly or yieldingly mounted cutting material bodies can adapt particularly well to changing inclinations of the inner surface of the bore in the axial direction of the bore, e.g. at the transition between a circular-cylindrical bore section and a conical bore section. Honing operations in which the cutting material body should follow the contour of the bore as well as possible without changing the macroscopic shape of the bore are also referred to here as "follow-up honing". The advantages of honing tools according to the invention can also be used in the honing of non-round bore shapes with deviations from rotational symmetry.

Numerous tests have shown that it is generally advantageous if the intermediate layer has a layer thickness in the range from 0.1 mm to 2 mm, in particular in the range from 0.5 mm to 1.5 mm. In the case of layer thicknesses that are well below the lower limit, the achievable ability to tilt the cutting material body relative to the cutting material body carrier element is generally not sufficient to be able to compensate for all misalignments that occur. With layer thicknesses that are well above the upper limit, it becomes more difficult to obtain sufficient stability of the cutting material strips against transverse loads.

In order to allow a good compromise between sufficient stability of the intermediate layer against transverse loads and sufficient flexibility to compensate for misalignments, it has proven to be advantageous for the intermediate layer to have a Shore hardness in the range of approx. 70 Shore-A to 95 Shore-A . With greater hardness, sufficient resilience is usually no longer given. In the case of significantly lower hardnesses, the arrangement of the cutting material strips on the cutting material body carrier element can become too unstable, so that during honing, sufficient machining forces can no longer be applied to the surface to be machined.

In preferred embodiments, the intermediate layer has an elastic layer made from an elastomer, in particular from a rubber-elastic polyurethane elastomer. The term "elastomer" stands for dimensionally stable but elastically deformable plastics whose glass transition point is below the service temperature. An elastomer can deform elastically under tensile and compressive loads, but then returns to its original shape undeformed shape. Such elastomers can be produced, for example, by vulcanizing natural rubber or silicone rubber. Adhesive elastomers are particularly useful. An advantage of polyurethane elastomers lies in the particularly high resistance of the material properties to the influence of typical cooling lubricants.

In some embodiments it is provided that the intermediate layer is vulcanized directly onto a contact surface on the cutting material body or onto the outer surface of the cutting material body carrier element. In this case, no additional material (such as an adhesion promoter or an adhesive) is required to create the connection between the intermediate layer and the element adjacent to it. The surface connection to the other element (cutting material body or outer surface of the cutting material body carrier element) can be realized, for example, by a thin layer of adhesive.

In some embodiments, the intermediate layer has a multi-ply or multi-layer structure. In particular, the intermediate layer can be constructed in such a way that it has a first layer and at least one second layer connected to it over a large area, the first layer being a layer of an elastomer and the second layer being an adhesive layer connected to the first layer over a large area.

Although it is possible for the adhesive layer (second layer) to be thicker than the elastomeric layer (first layer), it is preferably provided that the layer thickness of the first layer is greater than the layer thickness of the second layer. It can thereby be achieved that the essential contribution to the desired elasticity or flexibility of the cutting material body in relation to the cutting material body carrier element is determined by the properties of the first layer (elastomer layer).

It is possible that an optionally relatively small contribution to the overall elasticity of the intermediate layer is made by the adhesive layer. This can be achieved in that the adhesive layer itself is elastically deformable. To produce the adhesive layer, viscoplastic adhesives, for example a viscoplastic two-component plastic adhesive based on acrylate, can be used, for example. When selecting the material for the adhesive layer, it should preferably be ensured that there is good adhesion to the material of the cutting material body and/or to the material on the outside of the cutting material body carrier element.

To improve adhesion at a splice, at least one of the surfaces adjacent to the adhesive layer may be roughened by sandblasting, grinding, or other means prior to application of the adhesive. The mean peak-to-valley height R _z of a surface of a cutting material body carrier made of steel, for example, and/or of the cutting material body adjoining the adhesive layer is preferably in the range from R _z =10 μm to R _z =30 μm. As a result, permanently high adhesive strengths can be achieved. The surface of the interlayer material that will come into contact with the adhesive (eg polyurethane elastomer sheet or strip) can also be roughened beforehand. Average peak-to-valley heights in the range from _Rz =15 μm to _Rz =40 μm have proven to be particularly favorable.

The invention can be used with different types of honing tools. For example, the carriers of the cutting material body can be longer in the axial direction than in the circumferential direction. In contrast, in many embodiments, the cutting assembly has an axial length, measured in the axial direction, that is less than an effective outside diameter of the cutting assembly when the cutting material bodies are fully retracted. Such a cutting group can be referred to as an annular cutting group. In the case of an annular cutting group, too, cutting material bodies can be designed as cutting material strips which are narrow in the circumferential direction and whose width in the circumferential direction is small compared to the axial length of the cutting material strips.

The honing tool preferably has exactly one annular cutting group. A ring-shaped cutting group can be designed in such a way that in the axial section covered by the ring-shaped cutting group there can be significantly more contact surface between cutting material bodies and bore inner surface than in a comparably narrow axial section of a conventional honing tool with relatively narrow honing stones.

The axial length of the cutting material bodies can be less than 40% or less than 30% of the effective outside diameter of the honing tool, for example, in particular between 15% and 30% of this outside diameter. In the case of honing tools for machining typical cylinder bores in engine blocks for cars or trucks, the axial length can be in the range from 5 mm to 40 mm, in particular 10 mm to 35 mm. Based on the bore length of a bore to be machined, the axial length can be less than 20% or less than 10% of this bore length, for example. Based on the bore diameter of a bore to be machined, the axial length can be in the range of 20% to 50% of the bore diameter, for example.

Since the cutting material bodies in such a ring-shaped cutting group are relatively short in the axial direction compared to conventional honing stones, even with stable intermediate layers with a relatively small thickness (e.g. 0.5 mm to 1.5 mm), sufficiently strong angles of inclination can be set between the cutting material body and the tool axis. thereby favoring a particular ability to follow contours.

If at least three cutting material body carriers are provided in the cutting group, the machining forces can be distributed well and relatively evenly over the entire effective outer diameter of the honing tool available through expansion over the circumference of the cutting group. For example, exactly three, exactly four, exactly five, exactly six, exactly seven or exactly eight cutting material body carriers of the same or different circumferential width can be provided in the cutting group. Although more than eight cutting material body carriers within a cutting group are possible, they make the construction more complicated and are usually not necessary. In some cases, it may also be sufficient if the honing tool only has two cutting material body carriers.

The invention also relates to a fine-machining method for machining the inner surface of a bore in a workpiece, in particular for fine-machining cylinder running surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating engines. In the course of the finishing process, at least one honing operation is carried out in which an expandable honing tool is moved up and down within the bore to generate a lifting movement in the axial direction of the bore and is simultaneously rotated to generate a rotary movement superimposed on the lifting movement. In this honing operation, a honing tool according to the claimed invention is used. This honing operation is preferably the last fine machining operation of a multi-stage fine machining process and essentially determines the surface structure of the end product.

Before the start of the honing operation, a bore shape that deviates significantly from a circular cylinder shape can be produced by fine boring (with geometrically defined cutting edges), by honing (with geometrically undefined cutting edges) or by a combination of both fine machining processes (e.g. first fine boring, then honing). For example, the bore can be pre-machined in such a way that, before the start of the honing operation, it is given an axial contour (e.g. barrel shape, bottle shape or cone shape) and/or one or more sections with a deliberately non-round shape (e.g. oval shape or cloverleaf shape). The honing operation can then be carried out while essentially preserving the shape so that the final desired surface structure is produced on the inner surface of the bore using the honing tool, essentially without changing the macro-shape of the bore. The bodies of cutting material run after or follow the previously defined surface shape, the individually resilient mounting of the individual bodies of cutting material resulting in a particularly good suitability for tracking.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine schrägperspektivische schematische Ansicht einer Ausführungsform eines Honwerkzeugs gemäß der beanspruchten Erfindung;

Fig. 2

eine schematische Schnittdarstellung durch einen Teil eines Schneidstoffkörper-Trägers, an dessen Außenseite mehrere Schneidstoffleisten jeweils unter Zwischenschaltung einer elastisch nachgiebigen Zwischenschicht befestigt sind;

Fig. 3

eine schematische Darstellung einer Bearbeitungssituation im Bereich eines Übergangs zwischen einen zylindrischen und einem konischen Abschnitt einer rotationssymmetrischen Bohrung mit axialem Konturverlauf;

Fig. 4

eine axiale Ansicht einer anderen Ausführungsform eines Honwerkzeugs;

Fig. 5

eine schematische Schnittdarstellung durch einen Teil eines Schneidstoffkörper-Trägers, an dessen Außenseite eine elastisch nachgiebige Schicht aufgebracht ist, die mehrere Schneidstoffkörper trägt, sowie ein vergrößertes Detail;

Fig. 6

in 6A und 6B ein erstes Ausführungsbeispiel mit lateral inhomogener Zwischenschicht; und

Fig. 7 - 9

weitere Ausführungsbeispiele mit lateral inhomogener Zwischenschicht.

Further advantages and aspects of the invention result from the claims and from the following description of preferred exemplary embodiments of the invention, which are explained below with reference to the figures. show:

1

Figure 12 is an oblique perspective schematic view of an embodiment of a honing tool according to the claimed invention;

2

a schematic sectional view through part of a cutting material body carrier, on the outside of which a plurality of cutting material strips are fastened, each with the interposition of an elastically resilient intermediate layer;

3

a schematic representation of a machining situation in the region of a transition between a cylindrical and a conical section of a rotationally symmetrical bore with an axial contour;

4

an axial view of another embodiment of a honing tool;

figure 5

a schematic sectional view through a part of a cutting material body carrier, on the outside of which an elastically flexible layer is applied, which carries a plurality of cutting material bodies, as well as an enlarged detail;

6

in FIGS. 6A and 6B a first exemplary embodiment with a laterally inhomogeneous intermediate layer; and

Figures 7 - 9

further exemplary embodiments with a laterally inhomogeneous intermediate layer.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The schematic 1 12 shows an oblique perspective view of a honing tool 100 according to an embodiment of the invention. The honing tool is used to machine an inner surface of a bore in a workpiece by means of honing and, in the example, is designed to hone cylinder running surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating engines. The honing tool is also particularly well suited for machining rotationally symmetrical bores that have bore sections of different diameters and/or different shapes, for example bottle-shaped bores, barrel-shaped bores and/or bores that have at least one conical bore section with a continuously variable axial diameter. However, the honing tool can also be used to machine circular cylindrical bores, i.e. rotationally symmetrical bores without an axial contour.

The honing tool has a material body 110 made from a steel material, which defines a tool axis 112, which is also the axis of rotation of the honing tool during honing. At the spindle-side end of the honing tool there is a coupling structure 120 for coupling the honing tool to a drive rod or a work spindle of a honing machine or another processing machine which has a work spindle which can be rotated around the spindle axis and oscillated back and forth parallel to the spindle axis .

For example, in embodiments for use on the work spindle of a machining center, a hollow shank taper or other taper type coupling structure may be provided.

On the end section of the tool body facing away from the spindle there is an expandable ring-shaped cutting group 130 with a large number of cutting material bodies 140-1, 140-2 etc. distributed around the circumference of the tool body, the axial length LS of which, measured in the axial direction, is several times smaller than an effective outer diameter AD of the cutting assembly 130 with the cutting material bodies fully retracted in the radial direction. The Cutting material bodies 140-1 etc. are designed as cutting material strips which are narrow in the circumferential direction and whose width BS measured in the circumferential direction is small compared to the axial length LS of the cutting material strips. An aspect ratio between length LS and width BS can be in the range from 4:1 to 20:1, for example. Expressed in absolute values, the length can be, for example, in the range from 10 mm to 20 mm and the width in the range from 2 mm to 5 mm.

The honing tool has only a single ring-shaped cutting group 130. This is arranged more or less flush with the end of the tool body remote from the spindle, so that, if necessary, blind bores can also be machined down to the bottom of the bore. An optionally available slim coupling section at the end of the honing tool facing away from the spindle is shown in dashed lines. This coupling section can, for example, be used as a coding element as part of an automatic tool change.

The cutting group or the cutting material bodies of the cutting group can be advanced radially to the tool axis by means of a cutting group infeed system assigned to the cutting group. Since this functionality, which is typical for honing tools, is known per se, the components provided for this (for example feed rod(s), expanding cone, etc.) are not described in detail here.

The expandable ring-shaped cutting group 130 comprises a plurality of radially advanceable cutting material body carriers 150-1, 150-2 etc., each of which covers a circumferential angular range which is greater than the axial length LS of the cutting material body or the cutting group. In the example of 1 six cutting material body carriers 150-1 to 150-6 are provided, each of which covers a circumferential angle range of between 45° and 60° and are arranged uniformly over the circumference of the honing tool.

Non-cutting guide strips 115-1 etc. are fastened to the tool body between immediately adjacent cutting material body carriers. 1 12 shows the honing tool 100 with the cutting material bodies pulled back, so that the outer surfaces of the guide rails serving as guide surfaces project beyond the abrasive outer surfaces of the cutting material bodies in the radial direction. Before and/or during the honing, the cutting material body carrier elements are fed radially outwards, so that they engage with the inner surface of the bore to be machined.

In the example, the cutting material body carriers are produced in one piece from a steel material and are therefore inherently essentially rigid. Each tool body carrier has one carrier section 152-1 etc. which is relatively wide in the circumferential direction, with a cylindrically curved outer side 154 and an essentially flat inner side which faces the tool body and on which a plate-shaped infeed section 156 projects inwards. On the inside of the infeed section facing away from the outside 154 there is an inclined surface which interacts with a corresponding inclined surface of an axially displaceable infeed cone in the manner of a wedge drive, so that an axial movement of the infeed rod inside the tool body leads to a radial movement of the cutting material body carrier. The infeed section 156 of the cutting material body carrier sits radially movable in a substantially rectangular recess of the tool body, so that a radial movement is possible, but tilting movements in the transverse direction are largely avoided. The tool body carriers are biased into the inwardly retracted position by a plurality of encircling coil springs so that the radial outward infeed occurs against the force of these return springs.

There are exemplary embodiments in which all cutting material body carriers or all cutting material bodies of the honing tool can be radially infed with a single common infeed (honing tools with a simple widening).

In the embodiment of the honing tool 100 in 1 is a honing tool with double expansion. The ring-shaped cutting group 130 has two groups of cutting material body carriers that can be advanced independently of one another, with the three cutting material body carriers of one group being circumferentially offset by 120° relative to one another, so that a cutting material body carrier of the other group is arranged between two adjacent cutting material body carriers of one of the groups is.

Special constructive precautions are taken on the honing tool, which can help to optimize the machining result on the bores machined with the honing tool in such a way that over the entire length of the bore, especially in the area of transitions between bore sections of different shapes and/or in the area of reversal points the axial honing movement, the desired surface structure can be produced with relatively uniform quality.

As in 1 recognizable, each cutting material body carrier has on its radial outer side 154 several cutting material bodies in the form of cutting material strips, which are arranged at a mutual circumferential distance from one another. These groups of cutting material bodies or groups of cutting material strips mounted together on a cutting material body carrier can, for example, consist of between three and ten cutting material strips consist. In the example case, seven cutting material strips are arranged at a uniform circumferential distance from one another on each cutting material body carrier. In the case of the narrower cutting material strips, the circumferential spacing is approximately of the order of magnitude of the width of the cutting material strips or greater, and in the case of the wider cutting material strips approximately the size of the width of the cutting material strips or less.

The cutting material bodies are not rigidly connected to the cutting material body carrier that carries them. Instead, there is a gap between each of the cutting material strips and the cutting material body carrier carrying the cutting material strip, in which an elastically flexible intermediate layer 160 is arranged, which essentially completely fills the gap between the cutting material strip and the cutting material body carrier element. The elastically yielding intermediate layer means that the cutting material bodies can move to a limited extent relative to the cutting material body carrier under external stress and against the restoring force through the intermediate layer. The cutting material strips each have individual flexibility, so they can each shift slightly independently of the adjacent cutting material strips.

In the example, the intermediate layer has a layer thickness SD of approx. 1 mm, as a result of which a good compromise can be achieved between sufficient flexibility and sufficient stability of the cutting material body against transverse forces. The intermediate layer essentially consists of a rubber-elastic polyurethane elastomer with a hardness in the hardness range of between 75 and 85 Shore A. Suitable elastic polyurethane plastics are commercially available, for example, under the trade names Vulkollan® ^{or Urepan®} . The intermediate layer material is non-porous, i.e. impermeable, so that no cooling lubricant can penetrate and the elastic properties remain permanent. The material is also chemically resistant to cooling lubricants and mechanically sufficiently resistant to the abrasion of the honing process in the harsh machining environment.

When manufacturing the honing tool, it is possible to first glue prefabricated, narrow, thin strips of the intermediate layer material to the outside of the cutting material body carrier and then to glue the provided strip-shaped cutting material bodies (cutting material strips) using a suitable adhesive.

A variant of the production does not require an adhesion promoter between the intermediate layer material and the cutting material bodies. In this variant, a plate is first produced from cutting tool body material. After that, a layer of the precursor of the Finished intermediate layer material is vulcanized, so that a mechanically strong adhesive contact between the cutting material body material and the intermediate layer material is created by the vulcanization. The individual cutting material bodies, each provided with an intermediate layer, can then be produced by separating the coated cutting material body plate. It would also be possible to provide individual strips of cutting material with a vulcanized elastomer layer on one side and then to glue this onto the carrier element of the cutting material body.

It is also possible first to coat the outside of a cutting material body carrier element more or less over the entire surface with a layer of intermediate layer material (eg by gluing) and then to attach the cutting material strips to the intended locations by gluing. The intermediate layer material then remains free between adjacent cutting material strips (cf. figure 5 ).

In preferred embodiments, a tough-elastic two-component construction adhesive based on acrylate is used to produce a planar adhesive connection between a cutting material body and a strip of elastic intermediate layer material and/or an adhesive connection between an intermediate layer made of polyurethane plastic and the outside of the cutting material body support element. The resulting bond is characterized by high adhesive strength. In addition, the adhesive layer is slightly elastic in itself, so that a multi-layer, elastically flexible intermediate layer is created that offers good adhesion even after permanent alternating stress.

An improvement in the adhesive strength can be achieved if the surfaces of the intermediate layer material, the cutting material body carrier and/or the cutting material body which come into contact with the adhesive have a relatively rough surface structure. If necessary, the surfaces can be roughened before the adhesive is applied by grinding, sandblasting or in some other way, eg to an average surface roughness in the range from R _z = 15 µm to R _z = 30 µm.

By interposing an elastically resilient intermediate layer between the cutting material strips and the cutting material body support elements, the ability of the honing tool to follow contours when machining and/or producing bores with an axial contour course can generally be improved, since the cutting material strips align slightly with respect to the rigid cutting material body support element can thus achieve a more even contact pressure on the inner surface of the bore.

A special phase of processing is in 3 shown schematically. A section of a workpiece 300 in the form of an engine block (cylinder crankcase) for an internal combustion engine can be seen. The bore 320 to be machined is delimited by an inner surface 322 of the bore. The inner surface of the bore is the workpiece surface to be machined during honing. The bore 320 is rotationally symmetrical with respect to its bore axis (not shown) and extends over a bore length from the illustrated bore entry 314, which faces the cylinder head in the installed state, to an axially opposite bore exit. The bore can be subdivided into a plurality of bore sections which are axially adjacent and have different functions, which merge into one another in a sliding manner, ie without the formation of steps or edges. A first bore section 322 begins directly at the bore entrance 314, which should have an essentially circular-cylindrical shape, ie no axial contour course, after the machining has been completed. A conical second bore section 324 adjoins this circular-cylindrical bore section in the direction of the opposite end of the bore, in which the bore diameter increases continuously from the inlet side in the direction of the outlet side. The conical bore section can extend to the bore outlet. It is also possible for the conical bore section to be followed by a further essentially circular-cylindrical section, which then has a larger diameter than the first bore section 322 on the inlet side. In such a case, the bore would then have at least approximately the shape of a bottle. The transition areas between the bore sections are (deviating from the schematic drawing) continuously curved. There can be convex or concave transition areas.

In the 3 shows a phase of honing, in which the annular cutting group 330, for example during a downward movement from the bore entry 314 in the direction of the bore exit, is at the level of a transition section 323 between the circular-cylindrical first bore section 322 and the conical second bore section 324 that follows downwards. The transition section generally has a slight rounding with a suitable transition radius, i.e. it is not sharp-edged. Coming from the cylindrical bore section, a leading part of the cutting material bodies 140 has already reached the conical bore section, in which the bore widens and the lateral surface of the bore is set at an angle or inclined relative to the bore axis. An axially unequal load can result here, which can lead to the generation of a tilting moment and possibly to a slight tilting of the cutting material carrier 150 . The elastically yielding intermediate layer 160 can compensate for part of this tilting by compressing the upper part more than the lower part leading to the end of the bore. This can also result in the honing of the conical Bore section results in relatively evenly distributed machining forces, so that the surface structure can remain relatively uniform over the entire length of the bore, ie including both the cylindrical bore section and the conical bore section as well as the transition section.

Due to the elastically resilient intermediate layer, the cutting material bodies can be tilted relative to the cutting material body carrier not only in the axial direction (about a tilting axis running tangentially to the honing tool), as is shown in 3 is shown schematically. Tilting in the circumferential direction is also possible to a small extent. This tilting movement can take place, for example, about a tilting axis that is essentially parallel to the axis. As a result, the cutting material bodies can also follow the inner surface of the bore with almost no constraining forces if the macroscopic shape of the inner surface of the bore in the machined section deviates significantly from a rotationally symmetrical shape. For example, bore sections with an oval shape or with a cloverleaf shape or out-of-roundness of higher orders or with irregular, non-rotationally symmetrical shapes can be machined by honing thanks to the individual flexibility of the cutting material bodies so that a relatively uniform Surface structure can be achieved. This is achieved, among other things, by the fact that the cutting material body can follow the predetermined surface shape to a certain extent due to the elastically flexible intermediate layer, so that pressure force peaks, such as could occur with cutting material bodies rigidly attached to the cutting material body carrier, are reduced or avoided. Thus, a relatively uniform depth of cut can be achieved over the entire inner surface of the bore, despite an out-of-round bore and/or axial bore contour. This can be favorable both for largely smooth end surfaces and for surfaces with a plateau structure. In this context it is also worth mentioning that the expansion force is usually a multiple of the "spring force" of the intermediate layer. This results in a relatively even cutting depth, even with "bumps", which usually only represent radial deviations of a few µm.

In the case of the honing tool 100 with a double expansion, the three cutting material body carriers in a group are circumferentially offset from one another by 120°. The cutting material bodies of a group are preferably identical to one another. The cutting material bodies of a first group preferably differ from the cutting material bodies of a second group. For example, the cutting material bodies of the two groups can have different widths and/or they can be attached to the cutting material body carriers with different circumferential spacings and/or different divisions. It is possible that the cutting material body of one of the groups for a coarser machining with a coarser grain and the tool bodies of the other group are provided with finer grain for finer machining. It is also possible that not all cutting material bodies of a ring-shaped cutting group are fastened to the associated cutting material body carriers by means of an elastically yielding intermediate layer. It may be the case, for example, that in a first group the cutting material bodies sit directly on the cutting material body carrier without the interposition of an elastic intermediate layer and are therefore rigidly connected to it, while in the other group the cutting material bodies are individually flexible via an elastic intermediate layer on the cutting material body carrier are attached. For example, a first group can be provided which is intended for contour honing and has cutting strips rigidly connected to the cutting material body carriers, while the second group is provided for a subsequent finish honing process and is equipped with cutting material bodies which are attached in a flexible manner relative to the cutting material body carrier are. In another process chain, it is also possible to design a first group for an intermediate honing process and the second group for the subsequent finish honing process, with the cutting material bodies of both cutting groups being attached in an elastically yielding manner to the associated cutting material body carriers.

Based on 4 a honing tool 400 according to another embodiment will be explained. 4 shows the honing tool in an axial view from the end facing away from the spindle. The honing tool has a single annular cutting group 430, which is arranged on the end region of the tool body remote from the spindle and has a total of eight cutting material body carriers 450-1 to 450-8, which can each be advanced radially to the tool axis 412 and each cover a circumferential angle range that is greater than the is the axial length of the cutting material body or the cutting group. Each of the cutting material body carriers covers a circumferential area of approx. 40°.

The cutting material body carriers 450-1 and 450-2, together with the respective diametrically opposite cutting material body carriers 450-5 and 450-6, belong to a first group of cutting material body carriers which carry relatively narrow cutting strips 440-1. The cutting material body carriers 450-3, 450-4, 450-7 and 450-8 belong to a second group of cutting material body carriers, whose cutting material body carriers each carry cutting strips 440-2 with a somewhat larger circumferential width. Non-cutting guide rails 415-1 etc. are fixed between immediately adjacent pairs of cutting material body carriers, respectively. Immediately adjacent carriers of the cutting material body of the same group lie next to one another in the circumferential direction without an intermediate guide strip, while one of the guide rails is arranged between adjacent carriers of the cutting material body of different groups.

The four cutting material body carriers of a group can each be radially advanced and retracted together, the two groups can be radially advanced and retracted independently of one another. It is thus possible to carry out an upstream first honing operation with a first group, then withdraw this group, advance the other group radially and then carry out a downstream second honing operation with the cutting material bodies of the second group.

Based on figure 5 another possibility for fastening individual strip-shaped cutting material bodies 540-1 etc. to a common cutting material body carrier 552 is explained. In this exemplary embodiment, a thin, flexible plate 560' made of elastomer (thickness approx. 1 mm) is vulcanized or glued onto the cylindrically curved outer side 554 of the metal cutting material body carrier 552. The individual cutting material bodies 540-1 etc. are then glued to the outside of the elastomer layer. For this purpose, the outside 562 is first roughened by sandblasting, grinding or in some other way to an average peak-to-valley height of, for example, 20-40 μm. In addition, the rear side 542 of the body of cutting material, which is to be connected to the elastic intermediate layer, is also roughened by means of sandblasting, grinding or in some other way, with typical roughness depths usually being in the range between 10 μm and 20 μm. The adhesive for the adhesive layer 565 can be applied to one or both sides before the respective body of cutting material is pressed onto the outside of the elastomer plate at the intended point until the adhesive has hardened. By roughening the surfaces of the cutting material body and the elastomer plate adjoining the adhesive layer 565, the long-term adhesive strength can be significantly increased compared to surfaces that are not roughened. This flexible sheet 560' forms an elastomeric layer which, together with (at least) one adjacent adhesive layer 565, forms a multi-layered intermediate layer 560.

The intermediate layer can have spatially homogeneous elasticity properties in the region between the cutting material body carrier and the cutting material body carried by the intermediate layer, which can be achieved, for example, by an intermediate layer made of homogeneous elastic material completely filling the intermediate space. It is also possible for the intermediate layer to be designed in such a way that it is spatially inhomogeneous in the area that carries a cutting material body and/or has inhomogeneous elasticity properties, i.e. those elasticity properties that spread over the area used to carry a cutting material body can change to location.

For exemplary explanation show the Figures 6A, 6B as well as Figures 7 to 9 some variants of exemplary embodiments with spatially, in particular laterally, inhomogeneous intermediate layers.

The intermediate layer 660, which is Figure 6A in vertical section and in Figure 6B shown in top view, was made from a flat, plane-parallel piece of elastomer material, into which blind holes 662 of different depths and/or sizes were made according to a predetermined distribution from the side intended for carrying a cutting material body 640, e.g. by mechanical drilling or by laser machining. The holes can be evenly or unevenly distributed. They can also all have the same depth and/or the same diameter. The cutting material body 640 is glued to the free surface with multiple perforations and closes the holes on the outside, so that the intermediate layer is protected from the ingress of honing sludge or the like into the cavities on the circumference and from above and below.

7 12 shows a plan view of a flat intermediate layer 760 made of elastomeric material and shaped like a closed-peripheral frame with a single long internal cavity 762. FIG. After the associated cutting material body has been glued on, this cavity is also closed off on all sides.

In the variant of the intermediate layer 860 in 8 Slanting slots 862 are made in the original flat elastomeric material, which are similar to the holes in Figure 6A closed on the circumference after gluing on the carried cutting material body and are thus protected against the ingress of honing sludge etc.

These are some examples of intermediate layers that have more or less large cavities of different and/or the same shape and/or size and are therefore more elastically flexible than the corresponding elastomeric solid material into which the cavities (holes, slots or the like) are introduced became. Intermediate layers made of closed-pored elastomeric material are also possible, ie such elastomeric material in which cavities (closed pores) are already enclosed on all sides after manufacture.

In an embodiment of 9 the elastomeric material of the intermediate layer 960 completely fills the space between the cutting material body carrier and the cutting material body 940 . The elastomeric material is structured laterally and includes a succession of adjacent strips 964-1 of relatively softer elastomeric material and 964-2 of relatively harder elastomeric material.

The examples of Figures 6 to 9 illustrate that there are different possibilities, the elasticity properties of the intermediate layer by simple means exactly to the to adjust the intended use of the honing tool configured therewith. In each of the examples, a layer of elastomer material that is laterally structured by means of cavities and/or uneven material distribution is provided for this purpose. The layer thicknesses, which determine the distance between the carrier of the cutting material body and the cutting material body in the unloaded state, are usually in the range from 0.1 to 2 mm, in particular in the range from 0.5 to 1.5 mm.

The advantages of honing tools according to the invention can be achieved independently of the type of pre-machining of the bore to be honed. Before the start of the honing operation in which the honing tool is used, a bore shape that deviates significantly from the circular cylindrical shape can be produced by fine boring and/or by honing. With the help of the honing operation, the surface structure desired on the inner surface of the bore can be carried out essentially without changing the previously defined macro shape of the bore due to the use of a honing tool with individually flexible cutting material bodies.

Claims (13)

1. Honing tool (100, 400) for machining an inner face of a bore (320) in a workpiece (300) with the aid of at least one honing operation, in particular for honing cylinder surfaces in the production of cylinder blocks or cylinder liners for reciprocating piston engines, comprising:

   a tool body (110) that defines a tool axis (112, 412);

   an expandable cutting group (130, 430), attached to the tool body, having a plurality of radially feedable cutting material body carriers (150-1, 150-2, 450-1, 450-2) that each cover a circumferential angle range and are feedable radially with respect to the tool axis (112, 412) by means of a cutting group feeding system assigned to the cutting group (130, 430), wherein

   each cutting material body carrier (150-1, 150-2, 450-1, 450-2) carries, on its radial outer side (154, 454), a plurality of narrow cutting material bodies (140-1, 140-2, 140-3) configured as cutting material strips (140-1, 140-2, 140-3, 440-1, 440-2) that are narrow in the circumferential direction and have a width (BS) in the circumferential direction that is small compared with the axial length (LS) of the cutting material strips, wherein the cutting material bodies (140-1, 140-2, 140-3) are arranged at a mutual spacing from one another,

   characterized in that

   the honing tool (100, 400) is designed as a honing tool with double expansion,

   wherein the cutting group (130, 430) has a first group of cutting material body carriers (450-1, 450-2, 450-5, 450-6) and a second group of cutting material body carriers (450-3, 450-4, 450-7, 450-8) that is feedable independently of the first group,

   in the first group, the cutting material bodies are fastened directly to the associated cutting material body carrier without interposition of an elastic intermediate layer and are connected rigidly to the cutting material body carrier and,

   in the second group, the cutting material bodies are fastened to the associated cutting material body carrier in an individually resilient manner via an elastic intermediate layer (160, 560, 660, 760, 860, 960), wherein the elastic intermediate layer (160, 560, 660, 760, 860, 960) is arranged in an intermediate space between a cutting material body and the cutting material body carrier (150-1, 150-2, 450-1, 450-2) carrying the cutting material body, and fills the intermediate space between the cutting material body and the cutting material body carrier.
2. Honing tool according to Claim 1, characterized in that the cutting material bodies of the first group differ from the cutting material bodies of the second group, preferably in that the cutting material bodies of the two groups have different widths and/or have been applied to the cutting material body carriers with different circumferential spacings and/or a different pitch, and/or in that the cutting material bodies of one of the groups are provided with coarser grain for rougher machining and the cutting material bodies of the other group are provided with finer grain for finer machining.
3. Honing tool according to Claim 1 or 2, characterized in that the intermediate layer (160, 560, 660, 760, 860, 960) has a layer thickness (SD) in the range from 0.1 mm to 2 mm, in particular in the range from 0.5 mm to 1.5 mm.
4. Honing tool according to Claim 1, 2 or 3, characterized in that a Shore hardness of the intermediate layer (160, 560) is in the range from 70 Shore A to 95 Shore A.
5. Honing tool according to one of the preceding claims, characterized in that the intermediate layer (160, 560, 660, 760, 860, 960) has a layer made of an elastomer, in particular of a rubber-elastic polyurethane elastomer.
6. Honing tool according to one of the preceding claims, characterized in that the intermediate layer (160) has been vulcanized directly onto a contact face on the cutting material body (140-1, 140-2, 140-3) or the outer face (154) of the cutting material body carrier element.
7. Honing tool according to one of the preceding claims, characterized in that the intermediate layer (560) has a first layer and at least one second layer connected extensively thereto, wherein the first layer is a layer (560') made of an elastomer and the second layer is an adhesive layer (565) connected extensively to the first layer.
8. Honing tool according to one of the preceding claims, characterized in that the cutting group has an axial length (LS), measured in the axial direction, that is less than an effective outside diameter (AD) of the cutting group with cutting material bodies fully retracted, wherein preferably the honing tool has at least one of the following properties:

   (i) the axial length (LS) of the cutting material bodies is less than 40% of the effective outside diameter of the cutting group;

   (ii) the axial length (LS) of the cutting material bodies is in the range from 5 mm to 40 mm;

   (iii) the axial length (LS) of the cutting material bodies is less than 20% of the bore length of the bore;

   (iv) the axial length (LS) of the cutting material bodies is in the range from 20% to 50% of the bore diameter;

   (v) an aspect ratio between the axial length (LS) and the width (BS) of the cutting material bodies is in the range from 4:1 to 20:1.
9. Honing tool according to one of the preceding claims, characterized in that the cutting group (130, 430) has at least three cutting material body carriers, which are arranged such that machining forces over the entire effective outside diameter, available by expansion, of the honing tool are able to be distributed uniformly around the circumference of the cutting group, wherein the cutting group has preferably exactly four, exactly six or exactly eight cutting material body carriers of the same or different circumferential width.
10. Fine machining method for machining the inner face of a bore in a workpiece, in particular for fine machining cylinder surfaces in the production of cylinder blocks or cylinder liners for reciprocating piston engines,

    wherein the fine machining method comprises at least one honing operation in which an expandable honing tool is moved up and down within the bore in order to create a reciprocating movement in the axial direction of the bore and at the same time is rotated in order to create a rotary movement superimposed on the reciprocating movement,

    characterized in that

    a honing tool having the features of at least one of the preceding claims is used in the honing operation.
11. Fine machining method according to Claim 10, characterized in that, before the start of the honing operation, a bore shape that differs from the circular-cylindrical shape is created by fine boring and/or honing, and in that a honing operation for creating the desired surface structure on the bore inner face is carried out using the honing tool, substantially without changing the macro shape of the bore.
12. Fine machining method according to Claim 10 or 11, characterized in that in each case the cutting material body carriers of one group are radially fed and retracted jointly, wherein a prior first honing operation is carried out with the first group, this group is then retracted, the other group is radially fed, and then a following second honing operation is carried out with the cutting material bodies of the second group.
13. Fine machining method according to Claim 12, characterized in that the second honing operation is a tracking honing operation.

Images