WO2023089025A1

WO2023089025A1 - Honing tool and method for producing a honing tool

Info

Publication number: WO2023089025A1
Application number: PCT/EP2022/082268
Authority: WO
Inventors: Oliver Bachmann; Giorgio IANNUZZI; Robert Kapp; Florian KRANICHSFELD; Joachim Weiblen
Original assignee: Elgan-Diamantwerkzeuge Gmbh & Co. Kg
Priority date: 2021-11-22
Filing date: 2022-11-17
Publication date: 2023-05-25
Also published as: DE102021213090A1

Abstract

The invention relates to a honing tool (100) for machining the inner surface of a bore in a workpiece by means of at least one honing operation, comprising: a tool body (110) that defines a tool axis (112) and has a guide bore (115), which is coaxial to the tool axis, for receiving two adjusting elements which can be moved axially independently of each other, and a plurality of guide openings (160) which are distributed over the circumference of the tool body (110) and lead radially relative to the tool axis (112) from the guide bore (115) to an outer face of the tool body; a plurality of cutting means supports which each have a support section (152) that is wide in the circumferential direction and comprises an outer face for receiving cutting means, and have an adjusting section (158) that is narrower than the support section and has an inclined surface on the inner face facing away from the outer face for interacting with an associated inclined surface of one of the two adjusting elements. The adjusting sections of cutting means supports are each radially movably received in one of the guide openings. All the cutting means supports which can be adjusted via the first adjusting element form a first cutting group, and all the cutting means supports which can be adjusted via the second adjusting element form a second cutting group, wherein the tool body (110) has fourteen or more guide openings (160) which have an irregular angular division such that one or more of the guide openings has a different angular spacing (WA) from the directly adjacent guide openings in the circumferential direction.

Description

Honing tool and method for manufacturing a honing tool

FIELD OF APPLICATION AND PRIOR ART

The invention relates to a honing tool for machining a bore in a workpiece according to the preamble of claim 1. The invention also relates to a method for producing a honing tool.

The quality-determining final machining of tribologically stressable inner surfaces of bores, such as cylinder running surfaces in cylinder blocks (cylinder crankcases) or cylinder liners, is usually carried out using the "honing" fine machining process. Honing is a machining process with geometrically undefined cutting edges, which is carried out with an expandable honing tool. The honing process works with bonded cutting grain with constant surface contact between the abrasive working surface of the honing tool and the bore surface. The cutting grains are bound in a bond system (also referred to as "bond") and together with the bond system form an abrasive cutting surface. The binding system has the task of holding the bound cutting grains in place until they are blunted by the cutting process. Then they should be released so that new, still sharp-edged cutting grains can engage with the workpiece (self-sharpening effect).

In a typical honing operation, the honing tool is moved back and forth within the bore to be machined in the axial direction of the bore and at the same time rotated at a suitable speed to produce a rotary motion superimposed on the lifting motion. The cutting means attached to the honing tool are pressed against the inner surface to be machined via the infeed system with a pressure force acting radially to the tool axis. As the material is removed, the effective outer diameter of the honing tool is gradually increased by the infeed system. The delivery is therefore also referred to as "expansion", the delivery system also as "expansion system". During honing, a cross-hatch pattern typical of honing with crossing traces of processing, which are also referred to as “honing marks”, usually occurs on the inner surface.

A honing tool of the type considered in this application is a honing tool with double infeed or with double expansion, i.e. a honing tool that has two independent has cutting groups that can be delivered from one another. This means that multi-stage machining processes can sometimes be carried out without changing tools.

DE 10 2019 201 465 A1 discloses honing tools with double feed, which have two independently feedable cutting groups on their tool body. A first cutting group has a plurality of radially advanceable first cutting material carriers which cover a circumferential angle range of at least 20° on a radial outside and carry on the outside a single first cutting means which is wide in the circumferential direction or several narrow first cutting means which are arranged at a mutual distance from one another. A second cutting group has a plurality of second cutting means carriers which can be advanced radially and which each carry a single, narrow second cutting means in the form of a cutting strip on their radial outside. All of the cutting means of the first and second cutting groups are located in an axially short cutting area having a length measured in the axial direction which is substantially smaller than an effective outer diameter of the cutting groups when the cutting means is fully retracted.

WO 2018/149696 A1 (cf. DE 10 2017 202 573 A1) discloses, among other things, honing tools with a double expansion. In a first group, the cutting means are fastened directly to the associated cutting means carrier and are rigidly connected to the cutting means carrier, without the interposition of an elastic intermediate layer. In the second group, the cutting means are individually flexibly attached to the associated cutting means carrier via an elastic intermediate layer.

TASK AND SOLUTION

It is an object of the invention to provide a honing tool that is suitable for different honing tasks or that can be configured for different tasks with only little effort. In particular, it should be possible to produce surfaces of the highest quality.

To solve this problem, the invention provides a honing tool with the features of claim 1 ready. Furthermore, a method for producing a honing tool with the features of claim 13 is provided. Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated into the description by reference. The honing tool is a honing tool with double feed or double expansion, which means that two independently feedable cutting groups are attached to the tool body. Each of the cutting groups comprises a plurality of cutting-means carriers which can be radially infed together by axial displacement of the associated infeed element or expansion element. A special feature is that the tool body has fourteen or more guide openings. The guide openings have an unequal angular spacing in such a way that one or more of the guide openings have unequal angular distances to the two guide openings that are immediately adjacent in the circumferential direction.

Directly adjacent means in particular that no guide strip is arranged between directly adjacent guide openings. Differences in the angular distances can, for example, be on the order of about 1° or more, for example in the range from 0.8° to 3°.

The claimed invention as formulated in this way has been found in practice to be very advantageous over conventional double flared honing tools in several respects.

Honing tools according to this formulation of the invention differ from conventional honing tools with double infeed, among other things, by the large number of fourteen or more guide openings, in each of which a single cutting means carrier can be inserted, the outer side of which, in the circumferential direction, is relatively wide can be occupied by cutting means. In comparison to the prior art, increased cutting strip surfaces are thus possible in the sense that larger parts of the circumference can be covered with cutting means. Added to this is the uneven angular pitch, which differs from classic angular pitches. A classic angular division is an angular division in which the guide openings are distributed evenly over the circumference of the tool body, so that, for example, there are twelve guide openings each with an angular spacing of 30° or eight guide openings each with an angular spacing of 45° or six guide openings each with an angular spacing of 60°.

It has been shown that due to the certain asymmetry in connection with the large number of guide openings, honing tools of this type can be used particularly flexibly and advantageously for various applications and can produce very good results in terms of shape and surface quality. Among other things, this results in improved form values and roundness values, which means better support for the cutting sticks in the Workpiece is returned. In addition, it was possible to achieve more uniform surface characteristics, which is attributed, among other things, to the possibility of relatively high surface proportions of cutting media and the resulting lower specific contact pressures required. In addition, comparatively long service lives result from increased cutting surface areas over the circumference. Furthermore, the large number of guide openings in connection with the non-uniform angular division between the guide openings opens up the possibility of configuring such honing tools very flexibly for different applications by equipping the tool body with appropriately divided and designed cutting means carriers. Different first and second cutting groups can thus be formed, the group members of which can be expediently distributed over the circumference with different degrees of symmetry or asymmetry. Finally, the asymmetry of the angular pitch seems to reduce the tendency to generate vibrations during honing, which has a positive effect on the form and surface qualities that can be achieved.

The number of guide openings is preferably an even number, ie a number that can be divided by two, guide openings being arranged in pairs diametrically opposite one another with respect to the tool axis. If identical cutting tool carriers are attached to the tool body at pairs of diametrically opposite points with cutting tools attached in an identical manner, which belong to the same cutting group and are therefore fed together, the tool position in the bore is stabilized, which has an advantageous effect on the bore quality.

It has proven particularly advantageous if the number of guide openings cannot be divided by four. For example, the tool body may have exactly 14 (fourteen) pilot holes, or exactly 18 (eighteen) pilot holes, or exactly 22 (twenty-two) pilot holes. These can be distributed over the circumference of the tool body in such a way that there is twofold rotational symmetry about the tool axis, but no mirror symmetry with respect to a plane containing the tool axis. So some degree of asymmetry is possible.

Honing tools with different distributions of cutting means carriers between the first and the second cutting group are possible within the scope of the claimed invention. For the purposes of this application, the term "pitch" is intended to denote the number of guide openings, so that a "pitch of 14" corresponds to a honing tool with 14 guide openings distributed over the circumference. In contrast, the term "angular pitch" refers to the angular distances between the guide openings measured in the circumferential direction. The angular distances between the in Circumferentially lying centers of adjacent guide openings measured. An uneven angular division then means, among other things, that the unequal angular distances between immediately adjacent guide openings differ to an extent that is clearly outside the manufacturing tolerances, so that unequal angular distances can mean, for example, at least 1° angular difference.

In preferred embodiments, the distribution of the cutting means carriers between the first and second cutting group is made such that, with a total number of T cutting means carriers, one cutting means group has a number of T/2-1 cutting means carriers and the other cutting group has a number of T/2+1 cutting means carriers. In an embodiment with exactly fourteen guide openings, one cutting group has exactly six and the other cutting group has exactly eight cutting means carriers. These can be distributed in different ways over the circumference of the tool body, taking into account as a boundary condition that mutually identical cutting means carriers equipped with cutting means of the same cutting group are arranged at diametrically opposite guide openings.

In some embodiments, the honing tool has a guide assembly with a plurality of non-cutting guide pads, which are arranged on the tool body distributed according to a non-uniform angular pitch over the circumference of the tool body.

Four non-cutting guide strips are preferably arranged in pairs diametrically opposite one another on the tool body in such a way that tool body segments which lie between directly adjacent guide strips in the circumferential direction have different circumferential widths in pairs. Preferably, the division is such that in the tool body segments with the greater circumferential width, a number N and in the tool body segments with the smaller circumferential width, a number N−1 of guide openings are arranged directly next to one another.

According to a development, a particularly high degree of flexibility for different applications can be achieved in that the guide openings and/or the cutting-means carriers have an axial length that is greater than 50% of the maximum effective outer diameter of the honing tool. The axial length can be more than 80% of this outside diameter, it can possibly be larger than this outside diameter. A correspondingly axially long cutting area can thus be realized. However, it is still possible to configure the honing tool in such a way that cutting means only become effective in an axially significantly shorter area. This is made possible, among other things, by the fact that the carrier sections can be fitted with cutting strips of different lengths. In order to achieve a high degree of flexibility with regard to the distribution of the cutting means over the circumference of the honing tool, it is provided in preferred embodiments that the support sections have several, preferably two, three or four, mutually parallel receiving grooves on their outer sides for receiving a strip-shaped cutting means unit (cutting strip) exhibit. Such a cutting means unit can, for example, comprise a narrow plate-shaped base made of metal, on which the actual cutting means coating (cutting grains in a corresponding bond) is applied directly or with an adhesive layer or the like in between. Depending on the design of the cutting means carrier, the cutting means can be fitted with cutting means of different widths. Equipping with a single relatively long individual bar is also possible. The receiving grooves do not have to be equipped with cutting-means units that essentially fill the entire length of a receiving groove. It is also possible to fasten a significantly shorter strip-shaped cutting means unit in a long receiving groove, for example with a length that corresponds to less than 50% of the axial length of the carrier section. Honing tools of this type can thus also be configured in such a way that all the cutting means are accommodated in an axially relatively short cutting area, the axial length of which can be smaller than the effective outside diameter of the honing tool.

Such honing tools can be advantageous, for example, when it comes to machining and/or producing bottle-shaped, cone-shaped or barrel-shaped bores.

The invention also relates to a method for producing a honing tool for machining an inner surface of a bore in a workpiece. In the method, a tool body, which is designed in accordance with the claimed invention, is equipped with a large number of cutting-means carriers of the type described and associated infeed elements. By equipping the tool body with cutting tool carriers and infeed elements, different configurations of the honing tool can be implemented, which can be well adapted to the respective machining task.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and aspects of the invention result from the claims and from the description of exemplary embodiments of the invention, which are explained below with reference to the figures. 1 shows an oblique perspective view of a honing tool according to an embodiment of the invention;

Fig. 2 shows a longitudinal section in a plane that leads centrally through guide openings.

3 shows a longitudinal section in a plane that leads centrally through guide rails and measuring nozzle bores;

4 shows a section perpendicular to the tool axis through an untipped tool body;

Figures 5 to 8 show different configurations for loading the honing tool;

9 to 13 show different options for equipping cutting means carriers with cutting means.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows an oblique perspective representation of a honing tool 100 according to an embodiment of the invention. Fig. 2 shows a longitudinal section in a plane that leads centrally through guide openings. Fig. 3 shows a longitudinal section in a plane that runs centrally through guide rails and measuring nozzle bores. 4 shows a section perpendicular to the tool axis through the untipped tool body.

The honing tool is suitable and intended for machining the 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 can be used flexibly and can be prepared or configured for a wide variety of machining tasks in just a few simple steps. The honing tool can, for example, be used in various configurations for machining circular-cylindrical bores, i.e. rotationally symmetrical bores without an axial contour. With other configurations, it can also be used to machine 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 have conical bore section with axially continuously variable diameter.

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 . In FIG. 1, the coupling structure 120 is designed as a functional part of a bayonet connection. 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.

In the end section of the tool body facing away from the coupling structure 120 or the working spindle (not shown), there is the cutting area 130 of the honing tool, in which all abrasive cutting means (in the form of cutting strips, general reference number 170) are attached. The cutting area 130 is arranged more or less flush with the end of the tool body remote from the spindle in the end section of the tool body facing away from the spindle, so that blind holes can also be machined down to the bottom of the hole if necessary. Within the cutting area 130 there are many strip-shaped cutting means 170 (hereinafter also referred to as cutting strips) distributed around the circumference of the tool body. The length LSB of the cutting area is between 80% and 95% of the outer diameter AD of the honing tool. In the example, the outer diameter is of the order of 80 mm, it can be in the range of 60 mm to 90 mm, for example, but possibly also above or below.

The honing tool 100 has an integrated joint 190, with the aid of which the tool body 110 is coupled in a limited manner to the connection piece, which is used for connection to the work spindle of the processing machine. In the example, the joint 180 is designed as a ball joint, in which the joint ball 192 is formed at the lower end of the connection piece, while the corresponding bearing elements are attached with concave spherical bearing surfaces inside the tool body 110 . As a result, a limited mobility of the tool body relative to the connection piece is possible in an infinite number of directions running transversely to the tool axis the honing tool can follow particularly well, especially when reworking the inner surfaces of bores to improve the shape and surface quality of the lateral surfaces.

The honing tool 100 in FIG. 1 is a double flare honing tool. In the tool body, a guide bore 115 runs coaxially to the tool axis 112 to accommodate two tool-side infeed elements (or expansion elements). When the honing tool is assembled ready for use, a tubular first feed element 140-1 and a second feed element 140-2 guided coaxially therein are inserted into the guide bore. These are independently axially displaceable. Each of the feed elements has two axially offset conical sections 142-1 and 142-2, which are referred to here as feed cones or expansion cones and whose lateral surfaces form an axially displaceable inclined surface of the feed system.

The tool body has a plurality of axially elongate guide openings (general reference numeral 160) leading radially to the tool axis from the guide bore 115 to the outside of the tool body. In the tool body of the exemplary embodiment, fourteen guide openings 160 are formed, which are circumferentially distributed according to an uneven angular pitch. An uneven angular division means here, among other things, that one or more of the guide openings have unequal angular distances to those guide openings that are immediately adjacent in the circumferential direction without an intermediate guide strip.

Four non-deliverable, non-cutting guide strips 190-1 to 190-4 of a guide group are arranged diametrically opposite one another in pairs on the outside of the tool body. The guide pads are distributed with an uneven angular pitch, so that tool body segments that lie between immediately adjacent guide pads in the circumferential direction have different circumferential widths in pairs. For the narrower WS-S tool body segments, these are around 78° and for the wider WS-B tool body segments around 102°. There are four guide openings in each of the wider tool body segments, and only three in the narrower ones, arranged directly next to one another without guide strips in between. The guide group has a two-fold rotational symmetry with respect to the tool axis.

Two diametrically opposed guide rails 190-1 and 190-3 are designed as measuring rails. In the part of the cutting area that is farther from the coupling, they have a measuring area with three radial bores 195 that are offset axially relative to one another, which can be used as measuring nozzles of a pneumatic diameter measuring system. Do you want one measure a specific measuring level, the radial bores in this level are opened and the unused radial bores are closed.

The following can be seen particularly well in FIG. 4 . Each of the guide openings defines a center plane 162 containing the tool axis 112, which lies centrally between the parallel lateral boundary surfaces of the guide opening. The angular distance WA to an immediately adjacent guide opening corresponds to the angular distance between the center planes of the guide openings that are adjacent to one another. Within the narrower tool body segments WS-S, the central guide opening 160-4 has the same angular spacing of approximately 22° from the guide openings 160-3 and 160-5, which are adjacent in both directions in the circumferential direction. Within the wider tool body segments WS-B, the two middle guide openings 160-14 and 160-1 are at an angular distance of 22° from one another, while the guide openings 160-2, 160 -13 there is an angular distance of approx. 23°.

Thus, for each of the two middle guide openings 160-13 and 160-14, the angular distance to the two guide openings that are directly adjacent in the circumferential direction is different. The differences in the angular distance (approx. 1°) are well outside the manufacturing tolerances and in the order of a few percent (e.g. from 2% to 5%) of the absolute value of the angular distance. For reasons of symmetry, this uneven angular distribution is also found on the opposite side, i.e. in the other, wider tool body segment.

Those guide openings that are only indirectly adjacent to one another with an intermediate guide strip each have an angular spacing of approximately 34°. Thus, the angular distribution of the guide openings over the circumference is characterized by three different values for angular distances, namely four times approximately 22°, twice approximately 23° and four times approximately 34°. In this respect, too, there is an uneven or asymmetrical angular division.

When the honing tool is configured ready for use, the tool body 110 carries a multiplicity of cutting-means carriers (general reference number 150). The cutting means carriers are in each case one-piece components made of steel material, which are essentially rigid in themselves. Each of the cutting means carriers has a carrier section 152 which is relatively wide in the circumferential direction and which has on its outside a plurality of, preferably two, three or four, mutually parallel receiving grooves 156 lying in a common plane for receiving each have a strip-shaped cutting means unit. The circumferential width of the carrier sections is in the range from approx. 15° to approx. 20°.

On the essentially flat inner side of the carrier section, an infeed section 158, which is initially plate-shaped and then slightly narrows, protrudes inwards. On the inside of the infeed section facing away from the outside 154 there are inclined surfaces which interact 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 cone inside the tool body leads to a radial movement of the cutting-means carrier. The plate-shaped part of the infeed section 158 sits radially movable in the essentially rectangular guide opening 160 of the tool body, so that a radial movement (radial to the tool axis 112) is possible, but tilting movements in the transverse direction thereto are largely avoided. The cutting element carriers are prestressed into the inwardly retracted position by means of two encircling coil springs, so that the radial delivery to the outside takes place against the force of these return springs.

In the exemplary embodiment, all the cutting means are designed as cutting 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. An aspect ratio between length LS and width BS can be in the range from 4:1 to 55:1, for example. The axial length LS almost as large as the maximum effective outer diameter AD of the honing tool.

The honing tool 100 can be configured for different machining tasks without great effort. Two steps are usually necessary for a specific configuration. A first step includes equipping the tool body 110 with cutting means carriers that are equipped with suitable cutting means. The cutting means carriers are inserted from the outside into the guide openings 160 provided for them in the desired distribution for the two cutting groups.

In order to ensure that the cutting means carriers belonging to one cutting group are delivered together, while the cutting means carriers of the other group are not delivered when one delivery element is delivered, the configuration comprises, as a second step, the installation of corresponding first and second delivery elements. In the case of the honing tool, this is relatively easy because the feed elements are only secured against falling out and held in their position in the installed state by two screws engaging radially inwards. If the feed elements are to be exchanged, the retaining screws can be unscrewed and the feed elements attached to the free front side of the Tool body are removed from this. Feed elements suitable for the desired configuration can then be inserted into the guide bore 115 and secured against falling out by screwing in the retaining screw. There is a set of first and second infeed elements for each specific circumferential distribution of cutting-means carriers on first and second cutting groups.

Some of numerous different configurations for equipping the honing tool will now be explained by way of example with reference to FIGS. 9 to 13 illustrate different possibilities for equipping the cutting means carrier 150 with a suitable number of receiving grooves and for equipping the receiving grooves with different distributions and types of cutting strips.

5 to 8 each show an axial view of a ready-to-use equipped honing tool from below. The honing tool comprises a first cutting group, the cutting means carriers of which are fed together via a first feed element 140-1, and a second cutting group, the cutting means carriers of which are fed together via the second feed element 140-2. For easy differentiation of the cutting groups, the infeed sections of the cutting means carriers of the first cutting group are each marked in black, while the infeed sections of the second cutting group appear light.

Attention should also be paid to the number of receiving grooves 156, which are rectangular in cross-section, on the carrier sections of the cutting-means carriers. In the examples, cutting means carriers are shown with either three or four equidistant receiving grooves of the same dimensions. In all of the illustrated exemplary embodiments, the cutting-means carriers 150 of the first cutting group each have three comparatively wide receiving grooves, while the cutting-means carriers of the second cutting group each have four somewhat narrower receiving grooves. Other divisions are possible. For example, the same number of receiving grooves (e.g. two, three or four) can be provided everywhere.

The first cutting group comprises six cutting-means carriers, while the second cutting group comprises eight cutting-means carriers. The number of receiving grooves on the cutting means carriers thus corresponds in each case to half the number of cutting means carriers in a cutting group. In the examples, this division leads to the cutting means carriers of the first cutting group per carrier unit covering a larger part of the circumferential width with cutting means than the cutting means carriers of the second cutting group, where accordingly a smaller proportion of the circumferential surface of the Cutting means carrier is covered with cutting means. In all examples, therefore, the condition is met that the cutting means carriers of the cutting group that has fewer cutting means carriers, the outer surface of which is covered more densely with cutting means, viewed in the circumferential direction, than the cutting means carriers of the group with a greater number. However, the equipment can also be exchanged.

5 shows a first configuration of the division of the first and second cutting groups. Here all the cutting means carriers of the first cutting group are arranged in groups of three directly next to one another, that is to say without intervening cutting means carriers of the second cutting group. The four cutting means carriers per side of the second cutting group are also located directly next to each other. The members of the first cutting group are located in the narrower tool body segments WS-S between the guide pads that are closer together.

If all receiving grooves of the cutting-means carrier are equipped with cutting means, the first cutting group thus has 18 cutting strips and the second cutting group has 32 cutting strips. However, not all receiving grooves have to be occupied by cutting means. 9 to 13 show examples of different options for the assignment of receiving grooves, which can be selected here. When all receiving grooves are equipped, a similar shell effect can be achieved with the honing tool as with classic shell tools, which have two pairs of honing shells that are relatively wide in the circumferential direction, but with better force distribution. Because of this similarity to traditional shell tools, the configuration of FIG. 5 may also be referred to as "shell splitting." This division can be used, for example, when machining cylinder liners. Within the groups of three of cutting-means carriers of the first cutting group, the angular distances to the immediate neighbors of the same cutting group are the same in each case. In contrast to this, the angular division varies within the second cutting group, since there both an angular distance of 22° and an angular distance of 23° occur.

In this example, as in other examples, the non-uniform angular pitch between adjacent tool carriers can contribute to reducing the tendency to chatter during machining, as well as solving overlapping problems in so-called spiral honing, in which relatively high honing angles (up to, for example, in the order of 140°) is worked.

A second configuration is shown in FIG. This can also be referred to as "light shell division". You can, inter alia, in the processing of cylinder liners or in the Machining unstable components can be used to advantage. Geometric weaknesses in cylinder bores can be bridged by dividing the cutting tool carrier in this way, resulting in better form and roundness values. A characteristic of this division is that within the larger tool body segments WS-B (where four guide openings are next to each other) cutting tool carriers of the different groups lie alternately next to each other, so that each cutting tool carrier has direct neighbors of the other cutting group. In the narrower tool body segments (with three guide openings per side) there is a pair of adjacent cutting means carriers of the second cutting group and additionally one of the first cutting group.

A third configuration is shown in FIG. Here, too, the cutting-means carriers of the two cutting groups are nested or mixed into one another. In the narrower tool body segments WS-S (each with three guide openings), the different cutting tool holders are arranged alternately next to each other, while in the wider tool body segments WS-B (with the four guide openings) two cutting tool holders of the first cutting group are arranged in the middle directly next to each other are. This configuration results in a pairwise symmetrical division of the second cutting group. There are two diametrically opposite pairs, each in wider tool body segments, which are fed together, and essentially orthogonally thereto in the center within the narrower tool body segments, one member of the second cutting group. These act partly as support strips. This configuration can be used with particular advantage when processing unstable components. Here, too, there is no fully symmetrical division in the first cutting group and the second cutting group.

A fourth configuration is shown in FIG. 8, which can be referred to as a “nearly symmetrical” split. Within the tool body segments between immediately adjacent guide rails there are no pairs of immediately adjacent cutting means carriers of the same cutting group. Rather, the cutting means carriers of the different groups are arranged alternately next to one another in the circumferential direction. This results in a relatively uniform distribution in almost regularly distributed areas of the circumference both in the first cutting group and in the second cutting group. Here, too, the arrangement is not completely symmetrical due to the different angular distances between adjacent guide openings, but there is a proportion of asymmetry which, according to the inventors' observations, significantly reduces the generation of vibrations during machining compared to more symmetrical arrangements. With this division of the cutting tool carrier can geometric weak points of Cylinder bores are well bridged, resulting in better shape and roundness values.

As already mentioned, the cutting means carriers can be variably fitted with cutting means of different widths and/or with different numbers of cutting means and/or with cutting means of different lengths. 9 to 13 show a small selection. In the figures, at the top left (partial figure A) is an axial view, at the top right (partial figure B) is a side view, at the bottom left (partial figure C) is a plan view and at the bottom right (partial figure D) is an isometric view of a cutting means carrier with cutting strips attached thereto (a or more) shown.

9 and 12 show examples in which a cutting means carrier with several (three or four) receiving grooves is occupied with only a single individual strip of the cutting means.

FIG. 11 shows an example in which all three receiving grooves of a cutting-means carrier are occupied by relatively wide cutting strips, which essentially extend over the entire length. Assemblies of the type shown in FIGS. 9, 11 and 12, ie with relatively long cutting strips that cover the greater part of the cutting area, are particularly well suited for machining and/or producing circular-cylindrical bores.

10 shows an example of an assembly in which a cutting means carrier is equipped with four long, narrow receiving grooves with four relatively short cutting strips whose axial length is less than half the axial length of the receiving grooves. The arrangement ensures that the areas covered with cutting tool are in the immediate vicinity of the free end of the honing tool. Such a tool can be used particularly well in so-called contour honing in order to machine or produce rotationally symmetrical bores with a bore shape that deviates from a circular cylinder, for example with a bottle shape, barrel shape or a tapered shape.

13 shows by way of example that it is also possible to equip one or both cutting groups as follows: The cutting means carrier 150, which has a T-shaped cross section, has three receiving grooves. The middle one is fitted with a single long cutting bar (over a substantial axial range, eg over 80% to 100% of the length of the receiving groove). Two relatively short cutting strips (e.g. approx. 10 mm to 15 mm to the left and right of the long cutting strip) are installed at the end to be attached away from the spindle. This arrangement is useful, for example, for workpieces with very little overflow, e.g. monoblocks, i.e. cylinder blocks with a cylinder head already cast in. Usually the overflow of these workpieces is less than 5 mm. In this application it is helpful to have more cutting material available in the lower area of the carrier in order to avoid a diameter drop in the lower area of the bore just before the start of the honing overflow.

The following explanations can be helpful for selecting the best-adapted configuration, i.e. an arrangement or distribution of the cutting strips that is well-adapted for a machining task.

Very stable bores (bores without local "weak points" such as non-existent stiffening ribs) or cylinder liners can be honed with a "shell arrangement" (see e.g. Fig. 5). This has the advantage that the tool run is very smooth and a possible tendency to chatter is prevented. A shell arrangement has proven to be useful for the first honing stage (roughing or pre-honing), especially with coated bores, since the geometric errors after coating are not insignificant. The shell arrangement prevents individual slats from cutting free and swinging open, since the opposing angular areas of the support slats are relatively narrow and the slats “tighten” one another accordingly.

With an almost completely symmetrical arrangement (see e.g. Fig. 8), local weak points in bores (e.g. missing stiffeners) or corresponding bore interruptions (e.g. in 2-stroke engines) can be better compensated and thus better results in terms of shape and surface can be achieved. Largely symmetrical arrangements also make sense for very thin-walled components in order to avoid "deformation" during processing. In the case of large honing angles (140°), the following also applies: the more evenly the ridges are distributed, the better or easier it is to achieve even coverage (or distribution) of the honing marks over the entire bore.

The divisions between the borderline cases "shell arrangement" (see Fig. 5) and "almost full symmetry" (see Fig. 8) can be viewed as a compromise. Example: Unstable bore with "weak spots", crankcase has an "unfavorable" resonance body and tends to honing noises that are louder than average. Chattering is avoided with a shell arrangement, but the honing quality tends to be poorer - with "full symmetry" the quality is significantly better, but the honing noises can also be significantly louder. There is also a risk of chattering. With the different distributions, good compromise solutions can be achieved for difficult bores. This makes the honing tool very flexible. The axial position of the measuring nozzles and the measuring level determined thereby can be adapted to the corresponding requirements. The axial position can be selected in such a way that it is approximately in the middle of the area covered with cutting means. As a production tool, the honing tool can be easily adapted to different machining tasks. Due to its flexibility of use, it is also very well suited as a test tool.

Claims

patent claims

1. Honing tool (100) for machining an inner surface of a bore in a workpiece using at least one honing operation, in particular for honing cylinder running surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating engines, comprising: a tool body (110) which defines a tool axis (112). , a guide bore (115) coaxial with the tool axis for receiving two axially displaceable infeed elements and a large number of guide openings (160) which are distributed over the circumference of the tool body (110) and extend from the guide bore (115) radially to the tool axis (112) lead to an outside of the tool body; a first feed element (140-1) and a second feed element (140-2) which are accommodated in the guide bore (115) and are axially displaceable independently of one another; a large number of cutting means carriers (150), each of which has a carrier section (150) which is wide in the circumferential direction and has an outer side for receiving cutting means and an infeed section (158) which is narrower relative to the carrier section and which on the inner side facing away from the outer side has an inclined surface for interacting with a associated inclined surface of one of the two feed elements (140-1, 140-2), the feed sections of cutting means carriers being radially displaceably received in one of the guide openings in each case; All cutting means carriers that can be fed via the first feed element (140-1) form a first cutting group and all cutting means carriers that can be fed via the second feed element (140-2) form a second cutting group, characterized in that the tool body (110) has fourteen or more guide openings (160) which have a non-uniform angular pitch in such a way that one or more of the guide openings has unequal angular distances (WA) to the immediately adjacent guide openings in the circumferential direction.

2. Honing tool according to Claim 1, characterized in that the number of guide openings is an even number, with guide openings lying diametrically opposite one another in pairs to the tool axis, with identical cutting means carriers of the same cutting group with cutting means fitted in an identical manner preferably being arranged in the guide openings (160) which are diametrically opposite to one another are.

3. Honing tool according to claim 1 or 2, characterized in that the number of guide openings (160) cannot be divided by four, the tool body (110) preferably exactly fourteen guide openings (160) or exactly eighteen guide openings or exactly twenty-two guide openings.

4. Honing tool according to one of the preceding claims, characterized in that the guide openings (160) are distributed over the circumference of the tool body (110) in such a way that there is two-fold rotational symmetry about the tool axis (112), but no mirror symmetry with respect to a plane containing the tool axis.

5. Honing tool according to one of the preceding claims, characterized in that with a number of T cutting means carriers, one of the cutting groups has a number of T/2-1 cutting means carriers and the other cutting group has a number of T/2+1 cutting means carriers, with preferably in each case Diametrically opposite guide openings identical to each other, equipped with cutting means cutting means carriers of the same cutting group are arranged.

6. Honing tool according to one of the preceding claims, characterized in that the honing tool has a guide group with a plurality of non-cutting guide strips (190) which are distributed on the tool body according to an uneven angular division over the circumference of the tool body (110).

7. Honing tool according to claim 6, characterized in that four non-cutting guide strips (190-1 - 190-4) are arranged in pairs diametrically opposite one another on the tool body in such a way that tool body segments lying between guide strips directly adjacent in the circumferential direction have different circumferential widths in pairs, a number N and in the tool body segments (WS-S) with the smaller peripheral width a number N-1 of guide openings (160) being arranged directly next to one another.

8. Honing tool according to one of the preceding claims, characterized in that the guide openings (160) and/or the cutting means carrier (150) have an axial length which is more than 50% of the maximum effective outer diameter (AD) of the honing tool, in particular between 80% and 95% of this outside diameter.

9. Honing tool according to one of the preceding claims, characterized in that carrier sections (152) on their outer sides have several, preferably two, three or four have mutually parallel receiving grooves (156) for receiving at least one strip-shaped cutting means unit (170).

10. Honing tool according to one of the preceding claims, characterized in that one, several or all receiving grooves are equipped with cutting means units (170) which essentially fill the entire length of a receiving groove.

11. Honing tool according to one of the preceding claims, characterized in that a short strip-shaped cutting means unit is arranged in at least one receiving groove, with the cutting means unit preferably having a length which corresponds to less than 50% of the axial length of the carrier section, with cutting means preferably exclusively in one are arranged axially short region having a length which is less than 50% of the axial length of the support portion.

12. Honing tool according to one of the preceding claims, characterized in that the tool body (110) is equipped according to a configuration selected from the following group: a first configuration, wherein on diametrically opposite sides all cutting means carriers belonging to one side of the first cutting group are arranged directly next to one another and offset in the circumferential direction thereto on diametrically opposite sides all cutting means carriers of the second cutting group belonging to one side are arranged directly next to one another; a second configuration wherein within the larger tool body segments (WS-B) cutting means carriers of the different cutting groups are alternately juxtaposed so that each cutting means carrier has direct neighbors of the other cutting group, and in the narrower tool body segments (WS-S) a pair of adjacent cutting means carriers same cutting group exists; a third configuration, in which the cutting means carriers of the two cutting groups are distributed over the circumference in a nested manner, with the narrower tool body segments (WS-S) cutting means carriers of different cutting groups lying alternately next to one another and in the wider tool body segments (WS-B) two cutting means carriers of the same Cutting group are arranged directly next to each other; a fourth configuration, wherein within the tool body segments between directly adjacent guide strips, cutting means carriers of the two cutting groups are arranged alternately next to one another in the circumferential direction. - 21 -

13. A method for producing a honing tool for machining an inner surface of a bore in a workpiece using at least one honing operation, in particular for honing cylinder running surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating engines, with the following steps:

Providing a tool body (110) which defines a tool axis (112), a guide bore (115) coaxial with the tool axis for receiving two independently axially displaceable feed elements and a number of fourteen or more guide openings (160) which are radial to the tool axis from the guide bore (115) leading to an outside of the tool body and distributed according to an unequal angular pitch over the circumference, such that one or more of the guide openings has unequal angular distances to the immediately adjacent guide openings in the circumferential direction;

Equipping the tool body with cutting means carriers (150), each of which has a carrier section (152) which is wide in the circumferential direction and has an outer side (154) for receiving cutting means (170) and an infeed section (158) which is narrower relative to the carrier section and which is on the outer side inner side facing away from an inclined surface for cooperation with an inclined surface of an infeed element (140-1, 140-2), wherein the infeed sections of cutting means carriers are introduced in the radial direction into one of the guide openings in each case;

Equipping the tool body with a first feed element (140-1) and a second feed element (140-2) by inserting them into the guide bore (115), the cutting means carrier (150) and the feed elements (140-1, 140-2) depending on the configuration adapted to be selected in such a way that the first feed element acts only on the cutting means carrier of a first cutting group and the second feed element acts only on the cutting means carrier of a second cutting group.

14. The method according to claim 13, characterized in that the tool body (110) is equipped according to a configuration selected from the following group: a first configuration, in which all cutting means carriers belonging to one side of the first cutting group are directly next to one another on diametrically opposite sides are arranged and offset in the circumferential direction thereto on diametrically opposite sides all of the cutting means carriers belonging to one side of the second cutting group are arranged directly next to one another; a second configuration wherein within larger tool body segments (WS-B) cutter carriers of the different cutter groups are alternately juxtaposed such that each cutter carrier is direct neighbors of the other - 22 -

Has cutting group, and in narrower tool body segments (WS-S) there is a pair of adjacent cutting means carrier of the same cutting group; a third configuration, in which the cutting means carriers of the two cutting groups are distributed in a nested manner over the circumference, with narrower tool body segments (WS-S) cutting means carriers of different cutting groups lying next to one another alternately and in wider tool body segments (WS-B) two cutting means carriers of the same cutting group directly are arranged side by side; a fourth configuration, wherein within tool body segments between immediately adjacent guide strips, cutting means carriers of the two cutting groups are arranged alternately next to one another in the circumferential direction.