Honing tool and method for producing a honing tool

Description

FIELD OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a honing tool for machining a bore in a workpiece according to the preamble of claim 1. Furthermore, the invention relates to a method for producing a honing tool.

[0002] The quality-determining final machining of tribologically stressed inner surfaces of bores, such as cylinder bores in cylinder blocks (cylinder crankcases) or cylinder liners, is typically performed using the fine machining process "honing." Honing is a machining process with geometrically undefined cutting edges, which is carried out using an expandable honing tool. The honing process uses bonded cutting grains 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 layer. The bond system's task is to hold the bonded cutting grains in place until they are blunted by the cutting process.They should then be released so that new, still sharp-edged cutting grains can come into engagement with the workpiece (self-sharpening effect).

[0003] 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 simultaneously rotated at a suitable speed to generate a rotary motion superimposed on the reciprocating motion. The cutting media 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 resulting material is removed, the effective outer diameter of the honing tool is gradually increased via the infeed system. The infeed is therefore also referred to as "expansion," and the infeed system is also referred to as the "expansion system." Honing typically creates a cross-grinding pattern typical of honing on the inner surface, with intersecting machining marks, also known as "honing marks."

[0004] A honing tool of the type considered in this application is a honing tool with double infeed or double expansion, i.e., a honing tool that has two independently adjustable cutting groups. This allows multi-stage machining processes to be performed, in some cases, without tool changes.

[0005] DE 10 2019 201 465 A1 discloses honing tools with double infeed, which have two independently adjustable cutting groups on their tool body. A first cutting group has a plurality of radially adjustable first cutting material carriers, which cover a circumferential angular range of at least 20° on a radial outer side and carry a single circumferentially wide first cutting means or a plurality of narrow first cutting means arranged at a mutual distance from one another on the outer side. A second cutting group has a plurality of radially adjustable second cutting means carriers, each carrying a single narrow second cutting means in the form of a cutting bar on its radial outer side.All cutting means of the first and second cutting groups are arranged in an axially short cutting area which has a length measured in the axial direction that is substantially smaller than an effective outer diameter of the cutting groups when the cutting means are fully retracted.

[0006] WO 2018 / 149696 A1 (cf. DE 10 2017 202 573 A1) discloses, among other things, honing tools with double expansion. In a first group, the cutting elements are attached directly to the associated cutting element carrier without the interposition of an elastic intermediate layer and are rigidly connected to the cutting element carrier. In the second group, the cutting elements are individually flexibly attached to the associated cutting element carrier via an elastic intermediate layer. TASK AND SOLUTION

[0007] It is an object of the invention to provide a honing tool that is suitable for various honing tasks or can be configured for different tasks with minimal effort. In particular, it should enable the production of surfaces of the highest quality.

[0008] To achieve this object, the invention provides a honing tool having the features of claim 1. Furthermore, a method for producing a honing tool having the features of claim 13 is provided. Advantageous further developments are specified in the dependent claims. The wording of all claims is incorporated into the description by reference.

[0009] The honing tool is a double-feed or double-expansion honing tool, meaning that two independently adjustable cutting groups are mounted on the tool body. Each of the cutting groups comprises several cutting element carriers that can be radially advanced together via axial displacement of the associated feed 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 pitch, meaning that one or more of the guide openings are at unequal angular distances from the two immediately adjacent guide openings in the circumferential direction.

[0010] "Immediately adjacent" specifically means that there is no guide rail between directly adjacent guide openings. Differences in the angular distances can be on the order of approximately 1° or more, e.g., in the range of 0.8° to 3°.

[0011] The claimed invention according to this formulation has proven in practice to be very advantageous in several aspects compared to conventional honing tools with double expansion.

[0012] Honing tools according to this formulation of the invention differ from conventional honing tools with double infeed, among other things, in the large number of fourteen or more guide openings, into each of which a single cutting tool carrier can be inserted, the relatively wide outer side of which in the circumferential direction can be coated with cutting tools. This allows for larger cutting bar surfaces compared to the prior art, meaning that larger portions of the circumference can be coated with cutting tools. In addition, there is the uneven angular pitch, which differs from traditional angular pitches.A classic angular pitch is an angular pitch in which the guide openings are evenly distributed over the circumference of the tool body, so that, for example, there are twelve guide openings each spaced at 30°, or eight guide openings each spaced at 45°, or six guide openings each spaced at 60°.

[0013] It has been shown that the certain asymmetry combined with the large number of guide openings allows honing tools of this type to be used particularly flexibly and advantageously for a wide variety of applications, producing excellent results in terms of shape and surface quality. This results in, among other things, improved shape and roundness values, which are attributed to better support of the cutting edges in the workpiece. Furthermore, more uniform surface characteristics could be achieved, which is attributed, among other things, to the possibility of a relatively high surface area of cutting media and the resulting lower specific contact pressures. Furthermore, the increased cutting media surface area across the circumference results in comparatively long tool life.Furthermore, the large number of guide openings combined with the uneven angular pitch between the guide openings opens up the possibility of highly flexible configuration of such honing tools for different applications by equipping the tool body with appropriately divided and designed cutting medium carriers. This allows different first and second cutting groups to be formed, whose group members can be conveniently distributed around the circumference with varying degrees of symmetry or asymmetry. Finally, the asymmetry of the angular pitch appears to reduce the tendency to generate vibrations during honing, which, among other things, has a positive effect on the achievable shape and surface qualities.

[0014] Preferably, the number of guide holes is an even number, i.e., a number divisible by two, with guide holes arranged in pairs diametrically opposite each other to the tool axis. If identical cutting tool holders with identically mounted cutting tools are mounted on the tool body at diametrically opposite positions, which belong to the same cutting group and are thus fed together, this stabilizes the tool position in the bore, which has a beneficial effect on bore quality.

[0015] It has proven particularly advantageous if the number of guide openings is not divisible by four. For example, the tool body can have exactly 14 (fourteen) guide openings, or exactly 18 (eighteen) guide openings, or exactly 22 (twenty-two) guide openings. These can be distributed around the circumference of the tool body in such a way that there is twofold rotational symmetry around the tool axis, but no mirror symmetry with respect to a plane containing the tool axis. Thus, a certain degree of asymmetry is possible.

[0016] Within the scope of the claimed invention, honing tools with different distributions of cutting medium carriers between the first and second cutting groups are possible. For the purposes of this application, the term "pitch" refers to the number of guide openings, so that a "14 pitch" corresponds to a honing tool with 14 guide openings distributed around 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 are measured between the circumferential centers of adjacent guide openings. An uneven angular pitch then means, among other things, that the unequal angular distances between immediately adjacent guide openings differ by a degree that lies significantly outside the manufacturing tolerances, so that unequal angular distances can, for example, mean an angular difference of at least 1°.

[0017] In preferred embodiments, the distribution of the cutting means carriers between the first and second cutting groups is such that, with a total of T cutting means carriers, one cutting 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 exactly eight cutting means carriers. These can be distributed in different ways around the circumference of the tool body, whereby the boundary condition is that identical cutting means carriers of the same cutting group, equipped with cutting means, are arranged at diametrically opposite guide openings.

[0018] In some embodiments, the honing tool has a guide group with a plurality of non-cutting guide strips which are arranged on the tool body in a manner distributed over the circumference of the tool body according to an uneven angular pitch.

[0019] Preferably, four non-cutting guide rails are arranged in pairs diametrically opposite each other on the tool body such that tool body segments located between immediately adjacent guide rails in the circumferential direction have pairs of different circumferential widths. Preferably, the distribution is such that a number N of guide openings are arranged directly adjacent to one another in the tool body segments with the larger circumferential width, and a number N - 1 of guide openings are arranged directly adjacent to one another in the tool body segments with the smaller circumferential width.

[0020] According to a further development, particularly high flexibility for different applications can be achieved by enhancing the axial length of the guide openings and / or the cutting media carriers by more than 50% of the maximum effective outer diameter of the honing tool. The axial length can be more than 80% of this outer diameter and may even be larger than this outer diameter. This allows for a correspondingly long axial cutting area.

[0021] However, it is still possible to configure the honing tool so that cutting means are only effective in a significantly shorter axial area. This is made possible, among other things, by the fact that the carrier sections can be equipped with cutting bars of different lengths. In order to achieve great flexibility with regard to the distribution of the cutting means over the circumference of the honing tool, preferred embodiments provide for the carrier sections to have several, preferably two, three or four, parallel receiving grooves on their outer sides, each for receiving a bar-shaped cutting means unit (cutting bar). Such a cutting means unit can, for example, comprise a narrow, plate-shaped metal base to which the actual cutting means coating (cutting grains in a corresponding bond) is applied directly or with the interposition of an adhesive layer or the like.Depending on the design of the cutting tool carriers, the cutting tools can be equipped with cutting tools of varying widths. Equipping them with a single, relatively long, individual bar is also possible. The receiving grooves do not have to be equipped with cutting tool units that essentially fill the entire length of a receiving groove. It is also possible to attach a significantly shorter, bar-shaped cutting tool 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. This allows such honing tools to be configured so that all cutting tools are accommodated in a relatively short cutting area, the axial length of which can be smaller than the effective outer diameter of the honing tool.

[0022] Such honing tools can be advantageous, for example, when it comes to machining and / or creating bottle-shaped, conical or barrel-shaped bores.

[0023] The invention also relates to a method for manufacturing a honing tool for machining an inner surface of a bore in a workpiece. In the method, a tool body configured according to the claimed invention is equipped with a plurality of cutting tool carriers of the type described and associated feed elements. By equipping the tool body with cutting tool carriers and feed elements, different configurations of the honing tool can be realized, which can be well adapted to the respective machining task. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Further advantages and aspects of the invention emerge from the claims and from the description of embodiments of the invention, which are explained below with reference to the figures. Fig. 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 passes through the center of guide openings. Fig. 3 shows a longitudinal section in a plane that runs centrally through guide rails and measuring nozzle bores; Fig. 4 shows a section perpendicular to the tool axis through an unequipped tool body; Fig. 5 to 8 show different configurations for the honing tool; Fig. 9 to 13 show different possibilities for equipping cutting media carriers with cutting media. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Figure 1shows an oblique perspective view of a honing tool 100 according to an embodiment of the invention. Fig. 2 shows a longitudinal section in a plane that passes through the center of guide openings. Fig. 3 shows a longitudinal section in a plane passing through the center of guide rails and measuring nozzle bores. Fig. 4 shows a section perpendicular to the tool axis through the unloaded tool body.

[0026] 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 case, is designed to hone cylinder running surfaces in the manufacture of cylinder blocks or cylinder liners for reciprocating piston engines.

[0027] The honing tool is versatile and can be prepared or configured for a wide variety of machining tasks in just a few simple steps. For example, the honing tool can 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 for machining rotationally symmetrical bores with bore sections of different diameters and / or shapes, such as bottle-shaped bores, barrel-shaped bores, and / or bores with at least one conical bore section with a continuously variable axial diameter.

[0028] The honing tool has a material body 110 made of a steel material, which defines a tool axis 112, which simultaneously serves as the rotational axis of the honing tool during honing. At the spindle end of the honing tool is a coupling structure 120 for coupling the honing tool to a drive rod or a work spindle of a honing machine or other processing machine having a work spindle that is both rotatable about the spindle axis and oscillatable back and forth parallel to the spindle axis. Fig. 1 The coupling structure 120 is designed as a functional part of a bayonet connection. In embodiments for use on the work spindle of a machining center, a coupling structure in the form of a hollow shank taper or another taper can be provided, for example.

[0029] Located in the end section of the tool body facing away from the coupling structure 120 or the work spindle (not shown) is the cutting area 130 of the honing tool, in which all abrasive cutting means (in the form of cutting bars, general reference numeral 170) are mounted. 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 remote from the spindle, so that, if necessary, blind holes can also be machined down to the bottom of the hole. Within the cutting area 130, many bar-shaped cutting means 170 (hereinafter also referred to as cutting bars) are arranged distributed around the circumference of the tool body. The length LSB of the cutting area here is between 80% and 95% of the outer diameter AD of the honing tool. In the example, the outer diameter is on the order of 80 mm, but it can, for example, be in the range from 60 mm to 90 mm, if necessary.but also above or below.

[0030] The honing tool 100 has an integrated joint 190, by means of which the tool body 110 is coupled with limited mobility to the connecting piece, which serves 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 connecting piece, while the corresponding bearing elements with concave spherical bearing surfaces are mounted within the tool body 110. This allows for limited mobility of the tool body relative to the connecting piece in an infinite number of directions running transversely to the tool axis, whereby the honing tool can follow the inner surfaces of bores particularly well, particularly during the reworking of bore surfaces to improve the shape and surface quality of the lateral surfaces.

[0031] With the honing tool 100 in Fig. 1This is a honing tool with double expansion. A guide bore 115 runs coaxially to the tool axis 112 in the tool body for accommodating two tool-side feed elements (or expansion elements). In the ready-to-use honing tool, a tubular first feed element 140-1 and a second feed element 140-2, which is coaxially guided within it, are inserted into the guide bore. These are axially displaceable independently of one another. Each of the feed elements has two axially offset conical sections 142-1 and 142-2, respectively, which are referred to here as the feed cone or expansion cone, and whose lateral surfaces form an axially displaceable inclined surface of the feed system.

[0032] The tool body has a plurality of axially elongated guide openings (general reference numeral 160) that extend radially to the tool axis from the guide bore 115 to the outside of the tool body. Fourteen guide openings 160 are formed in the tool body of the exemplary embodiment, which are distributed over the circumference according to an uneven angular pitch. An uneven angular pitch here means, among other things, that one or more of the guide openings have unequal angular spacings from those guide openings that are immediately adjacent in the circumferential direction without an intermediate guide rail.

[0033] On the outside of the tool body, four non-adjustable, non-cutting guide rails 190-1 to 190-4 of a guide group are arranged in pairs, diametrically opposite each other. The guide rails are distributed at an uneven angular pitch, so that tool body segments located between immediately adjacent guide rails in the circumferential direction have pairwise different circumferential widths. These are approximately 78° for the narrower tool body segments WS-S and approximately 102° for the wider tool body segments WS-B. The wider tool body segments each have four guide openings, while the narrower segments have only three, arranged directly next to each other without any intermediate guide rails. The guide group exhibits twofold rotational symmetry with respect to the tool axis.

[0034] Two diametrically opposed guide rails 190-1 and 190-3 are designed as measuring rails. In the part of the cutting area farthest from the coupling, they feature a measuring area with three axially offset radial bores 195, which can be used as measuring nozzles of a pneumatic diameter measuring system. If a measurement is to be taken in a specific measuring plane, the radial bores located in this plane are opened, and the unused radial bores are closed.

[0035] In Fig. 4The following can be seen particularly clearly. Each of the guide openings defines a center plane 162 containing the tool axis 112, which lies centrally between the mutually 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 adjacent guide openings. Within the narrower tool body segments WS-S, the central guide opening 160-4 has the same angular distance of approximately 22° to the adjacent guide openings 160-3 and 160-5 in the circumferential direction in both directions. Within the wider tool body segments WS-B, the two middle guide openings 160-14 and 160-1 are located at an angular distance of 22° from each other, while the guide openings 160-2 and 160-13, which are located in the circumferential direction between a middle guide opening and the next guide bar, are at an angular distance of approximately 23°.

[0036] Thus, for each of the two central guide openings 160-13 and 160-14, the angular distance to the two guide openings immediately 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.

[0037] Those guide openings that are only indirectly adjacent to each other, with a guide rail in between, each have an angular spacing of approximately 34°. Thus, the angular distribution of the guide openings around the circumference is characterized by three different values for angular spacing: four times approximately 22°, two times approximately 23°, and four times approximately 34°. Thus, in this respect, there is also an uneven or asymmetrical angular spacing.

[0038] In the ready-to-use honing tool configuration, the tool body 110 carries a plurality of cutting tool carriers (general reference numeral 150). The cutting tool carriers are each one-piece components made of steel material, which are essentially rigid. Each of the cutting tool carriers has a carrier section 152 that is relatively wide in the circumferential direction and has, on its outer side, several, preferably two, three, or four, parallel receiving grooves 156 located in a common plane, each for receiving a strip-shaped cutting tool unit. The circumferential width of the carrier sections here is in the range of approximately 15° to approximately 20°.

[0039] On the essentially flat inner side of the carrier section, an initially plate-shaped, then slightly tapered feed section 158 protrudes inward. On the inner side of the feed section facing away from the outer side 154, there are inclined surfaces that interact with a corresponding inclined surface of an axially displaceable feed cone in the manner of a wedge drive, so that an axial movement of the feed cone inside the tool body leads to a radial movement of the cutting medium carrier. The plate-shaped part of the feed 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 are largely avoided.The cutting tool carriers are preloaded into the inwardly retracted position by means of two rotating coil springs, so that the radial outward feed occurs against the force of these return springs.

[0040] In the exemplary embodiment, all cutting elements are designed as circumferentially narrow cutting bars, whose circumferential width BS is small compared to the axial length LS. The aspect ratio between length LS and width BS can, for example, range from 4:1 to 55:1. The axial length LS is almost as large as the maximum effective outer diameter AD of the honing tool.

[0041] The honing tool 100 can be easily configured for different machining tasks. A specific configuration typically requires two steps. The first step involves equipping the tool body 110 with cutting media holders equipped with suitable cutting media. The cutting media holders are inserted from the outside into the designated guide openings 160 in the desired distribution for the two cutting groups.

[0042] In order to ensure that the cutting element carriers belonging to one cutting group are fed together, while the cutting element carriers of the other group are not fed when one feed element is fed, the configuration includes the installation of corresponding first and second feed elements as a second step. This is relatively simple with the honing tool because, when installed, the feed elements are secured against falling out and held in position by only two screws engaging radially inwards. If the feed elements need to be replaced, the retaining screws can be unscrewed and the feed elements removed from the free end of the tool body. 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.For each specific circumferential distribution of cutting medium carriers to first and second cutting groups, there is a set of first and second feed elements.

[0043] Based on the Fig. 5 to 8 Some of the numerous different configurations for equipping the honing tool are now explained as examples. Fig. 9 to 13 illustrate different possibilities for equipping the cutting means carriers 150 with a suitable number of receiving grooves and for equipping the receiving grooves with different distributions and types of cutting bars.

[0044] The Fig. 5 to 8Each shows an axial view of a ready-to-use honing tool from the underside. The honing tool comprises a first cutting group, whose cutting medium carriers are advanced jointly via a first advance element 140-1, and a second cutting group, whose cutting medium carriers are advanced jointly via the second advance element 140-2. To easily distinguish the cutting groups, the advance sections of the cutting medium carriers of the first cutting group are marked black, while the advance sections of the second cutting group appear light.

[0045] Attention should also be paid to the number of receiving grooves 156, which have a rectangular cross-section, on the support sections of the cutting tool carriers. The examples show cutting tool carriers with either three or four equidistant receiving grooves of the same dimensions. In all illustrated embodiments, the cutting tool carriers 150 of the first cutting group each have three comparatively wide receiving grooves, while the cutting tool carriers of the second cutting group each have four somewhat narrower receiving grooves. Other distributions are possible. For example, the same number of receiving grooves (e.g., two, three, or four) can be provided everywhere.

[0046] The first cutting group comprises six cutting medium carriers, while the second cutting group comprises eight cutting medium carriers. The number of receiving grooves on the cutting medium carriers thus corresponds to half the number of cutting medium carriers in a cutting group. In the examples, this distribution results in a larger portion of the circumferential width of the cutting medium carriers in the first cutting group being covered with cutting medium per carrier unit than in the cutting medium carriers in the second cutting group, where a correspondingly smaller portion of the circumferential surface of the cutting medium carrier is covered with cutting medium. In all examples, the condition is therefore met that the outer surface of the cutting medium carriers in the cutting group with fewer cutting medium carriers is more densely covered with cutting medium in the circumferential direction than the cutting medium carriers in the group with the larger number.However, the components can also be swapped.

[0047] Fig. 5 shows a first configuration of the division of the first and second cutting groups. Here, all cutting tool holders of the first cutting group are arranged in groups of three directly adjacent to one another, i.e., without any cutting tool holders of the second cutting group in between. The four cutting tool holders per side of the second cutting group are also located directly adjacent to one another. The members of the first cutting group are arranged in the narrower tool body segments WS-S between the closer-spaced guide rails.

[0048] If all the cutting tool holder slots are filled with cutting tool, the first cutting group will have 18 cutting tools, and the second cutting group will have 32 cutting tools. However, not all the cutting tools need to be filled with cutting tools. Fig. 9 to 13show examples of different options for the configuration of the receiving grooves that can be selected here. If all receiving grooves are equipped, the honing tool can achieve a similar shell effect as with classic shell tools, which have two pairs of relatively wide honing shells in the circumferential direction, but with better force distribution. Due to this similarity to traditional shell tools, the configuration of Fig. 5 also referred to as "shell spacing." This spacing can be used, for example, when machining cylinder liners. Within the groups of three cutting tool carriers in the first cutting group, the angular spacing to the immediate neighbors of the same cutting group is always the same. In contrast, the angular spacing varies within the second cutting group, as both angular spacings of 22° and 23° occur there.

[0049] In this example, as in other examples, the uneven angular pitch between adjacent cutting tool carriers can contribute to a reduction in the tendency to chatter during machining, as well as to solving overlap problems in so-called spiral honing, which involves working with relatively high honing angles (up to, for example, in the order of 140°).

[0050] In Fig. 6A second configuration is shown. This can also be referred to as "light shell division." It can be used advantageously, for example, when machining cylinder liners or unstable components. Geometric weak points in cylinder bores can be bridged by this division of the cutting tool carriers, 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 located next to each other), cutting tool carriers from the different groups are arranged 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 tool carriers from the second cutting group and an additional one from the first cutting group.

[0051] In Fig. 7a third configuration is shown. Here, too, the cutting medium carriers of the two cutting groups are nested or mixed within each other. In the narrower tool body segments WS-S (each with three guide openings), the different cutting medium carriers are arranged alternately next to each other, while in the wider tool body segments WS-B (with four guide openings), two cutting medium carriers of the first cutting group are arranged directly next to each other in the middle. This configuration results in a symmetrical division of the second cutting group in pairs. There are two diametrically opposed pairs in wider tool body segments, which are fed together, and essentially orthogonally to these, in the middle within the narrower tool body segments, there is one member of the second cutting group. These act in part as support strips.This configuration is particularly advantageous when machining unstable components. Here, too, there is no fully symmetrical pitch between the first and second cutting groups.

[0052] In Fig. 8A fourth configuration is shown, which can be described as a "virtually symmetrical" pitch. Within the tool body segments between immediately adjacent guide rails, there are no pairs of directly adjacent cutting element carriers of the same cutting group. Rather, the cutting element 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 spaced areas of the circumference for both the first cutting group and the second cutting group. Here, too, the arrangement is not completely symmetrical due to the different angular distances between adjacent guide openings; rather, there is a degree of asymmetry, which, according to the inventors' observations, significantly reduces the generation of vibrations during machining compared to more symmetrical arrangements.With this distribution of the cutting medium carriers, geometric weak points of cylinder bores can be easily bridged, resulting in better form and roundness values.

[0053] As already mentioned, the cutting tool holders can be variably equipped with different widths of cutting tools and / or with different numbers of cutting tools and / or with different lengths of cutting tools. Fig. 9 to 13 show a small selection. The figures show an axial view at the top left (part A), a side view at the top right (part B), a top view at the bottom left (part C), and an isometric view at the bottom right (part D) of a cutting tool carrier with one or more cutting bars attached to it.

[0054] The Fig. 9 and 12show examples in which a cutting tool holder with several (three or four) receiving grooves is occupied by only a single individual strip of the cutting tool.

[0055] Fig. 11 shows an example in which all three slots of a cutting tool holder are equipped with relatively wide cutting bars that extend essentially over the entire length. Equipment of the type shown in the Fig. 9 , 11 and 12 shown, i.e. with relatively long cutting bars that cover the larger part of the cutting area, are particularly well suited for machining and / or creating circular cylindrical bores.

[0056] Fig. 10shows an example of a configuration in which a cutting tool holder with four long, narrow receiving grooves is equipped with four relatively short cutting bars, the axial length of which is less than half the axial length of the receiving grooves. This arrangement ensures that the areas coated with cutting tool are located in the immediate vicinity of the free end of the honing tool. Such a tool is particularly well-suited for contour honing to machine or create 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.

[0057] Based on the Fig. 13As an example, it is shown that it is also possible to equip one or both cutting groups as follows: The cutting medium carrier 150, which has a T-shaped cross-section, has three mounting grooves. The middle one is equipped with a single long cutting bar (over a significant axial area, e.g. over 80% to 100% of the length of the mounting groove). Two relatively short cutting bars (e.g. approx. 10 mm to 15 mm to the left and right of the long cutting bar) are installed at the end to be mounted away from the spindle. This arrangement is useful, for example, for workpieces with very little overrun, e.g. monoblocks, i.e. cylinder blocks with a cylinder head already cast in. The overrun on these workpieces is usually less than 5 mm. In this application, it is helpful to have more cutting medium available in the lower carrier area in order to avoid a diameter reduction in the lower area of the bore, shortly before the honing overrun begins.

[0058] The following explanations may be helpful in selecting the best-suited configuration, i.e. an arrangement or distribution of the cutting bars that is well suited to a machining task.

[0059] Very stable bores (bores without local "weak points" such as missing stiffening ribs) or cylinder liners can be made with a "shell arrangement" (cf. e.g. Fig. 5 ). This has the advantage of ensuring very smooth tool travel and preventing potential chatter. A shell arrangement has proven particularly useful for the first honing stage (roughing or pre-honing) on coated bores, as geometric errors after coating are not insignificant. The shell arrangement prevents individual strips from cutting free and swinging open, as the opposing angle ranges of the support strips are relatively narrow, and the strips "clamp" each other accordingly.

[0060] With an almost completely symmetrical arrangement (cf. 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 for, thus achieving better results in terms of shape and surface finish. Largely symmetrical arrangements also make sense for very thin-walled components to avoid "deformation" during machining. For large honing angles (140°), the following also applies: the more even the honing strip distribution, the better or easier it is to achieve a uniform coverage (or distribution) of the honing marks across the entire bore.

[0061] The divisions between the borderline cases "shell arrangement" (cf. Fig. 5 ) and "almost full symmetry" (cf. Fig.8) can be considered a compromise. Example: A fragile bore with "weak spots"; a crankcase has an "unfavorable" resonance chamber and is prone to above-average honing noises. A shell arrangement avoids chatter, but tends to result in poorer honing quality. With "full symmetry," the quality is significantly better, but the honing noise can also be significantly louder. This also poses a risk of chatter. The different distributions allow for good compromise solutions for more difficult bores. This makes the honing tool very flexible.

[0062] The axial position of the measuring nozzles, or the resulting measuring plane, can be adjusted to meet specific requirements. The axial position can be selected so that it is approximately centered in the area covered with cutting media. As a production tool, the honing tool can be easily adapted to a variety of machining tasks. Due to its flexibility in terms of usage, it is also very well suited as a test tool.

Claims

1. Honing tool (100) for machining an inner face of a bore in a workpiece by means of at least one honing operation, in particular for honing cylinder run faces during production of cylinder blocks or cylinder liners for reciprocating piston engines, comprising: a tool body (110) which defines a tool axis (112) and has a guide bore (115) coaxial to the tool axis for receiving two axially movable feed elements, 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 outside of the tool body; a first feed element (140-1) and a second feed element (140-2) which are received in the guide bore (115) and are axially movable independently of one another; a plurality of cutting means carriers (150) which each have a carrier portion (150) which is wide in the circumferential direction and has an outside for receiving cutting means, and have a feed portion (158) which is narrower than the carrier portion and has a sloping face on the inside facing away from the outside for cooperating with an assigned sloping face of one of the two feed elements (140-1, 140-2), wherein the feed portions of cutting means carriers are each radially movably received in one of the guide openings; wherein all cutting means carriers which can be advanced via the first feed element (140-1) form a first cutter group, and all cutting means carriers which can be advanced via the second feed element (140-2) form a second cutter group, characterized in that 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.

2. Honing tool according to Claim 1, characterized in that the number of guide openings is an even number, wherein guide openings lie in pairs diametrically opposite one another relative to the tool axis, wherein preferably identical cutting means carriers of the same cutter group with cutting means provided in identical fashion are arranged in the guide openings (160) diametrically opposite one another.

3. Honing tool according to Claim 1 or 2, characterized in that the number of guide openings (160) is not divisible by four, wherein the tool body (110) has preferably precisely fourteen guide openings (160) or precisely eighteen guide openings or precisely twenty-two guide openings.

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

5. Honing tool according to any of the preceding claims, characterized in that for a number T of cutting means carriers, one of the cutter groups comprises a number T / 2-1 of cutting means carriers and the other cutter group a number T / 2+1 of cutting means carriers, wherein preferably, mutually identical cutting means carriers fitted with cutting means of the same cutter group are arranged at diametrically opposed guide openings.

6. Honing tool according to any of the preceding claims, characterized in that the honing tool has a guide group with multiple non-cutting guide strips (190) which are distributed on the tool body with an irregular 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 to 190-4) are arranged in pairs, diametrically opposite, on the tool body, such that tool body segments lying between directly adjacent guide strips in the circumferential direction in pairs have different circumferential widths, wherein preferably in the tool body segments (WS-B) with the greater circumferential width, there is a number N, and in the tool body segments (WS-S) with the smaller circumferential width, there is a number N-1 of guide openings (160) arranged directly next to one another.

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

9. Honing tool according to any of the preceding claims, characterized in that carrier portions (152) have on their outsides multiple, preferably two, three or four, mutually parallel receiving grooves (156), each for receiving at least one strip-like cutting means unit (170).

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

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

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

13. Method for producing a honing tool for machining an inner face of a bore in a workpiece by means of at least one honing operation, in particular for honing cylinder run faces during production of cylinder blocks or cylinder liners for reciprocating piston engines, with the following steps: provision of a tool body (110) which defines a tool axis (112) and comprises a guide bore (115) coaxial to the tool axis for receiving two mutually independently axially movable feed elements, and a number of fourteen or more guide openings (160) which lead radially relative to the tool axis from the guide bore (115) to an outside of the tool body and are distributed over the circumference with an irregular angular division, such that one or more of the guide openings have different angular spacings from the directly adjacent guide openings in the circumferential direction; equipping the tool body with cutting means carriers (150) which each have a carrier portion (152) which is wide in the circumferential direction and has an outside (154) for receiving cutting means (170), and have a feed portion (158) which is narrower than the carrier portion and has a sloping face on the inside facing away from the outside for cooperating with a sloping face of a feed element (140-1, 140-2), wherein the feed portions of cutting means carriers are each inserted into one of the guide openings in the radial direction; equipping the tool body with a first feed element (140-1) and a second feed element (140-2) by insertion into the guide bore (115), wherein the cutting means carriers (150) and the feed elements (140-1, 140-2) are adapted to one another configuration-dependently, such that the first feed element acts only on cutting means carriers of a first cutter group and the second feed element acts only on cutting means carriers of a second cutter group.

14. Method according to Claim 13, characterized in that the tool body (110) is equipped according to a configuration which is selected from the following group: a first configuration, in which on diametrically opposite sides, all cutting means carriers of the first cutter group belonging to one side are arranged directly next to one another, and offset thereto in the circumferential direction, on diametrically opposite sides, all cutting means carriers of the second cutter group belonging to one side are arranged directly next to one another; a second configuration, in which within larger tool body segments (WS-B), cutting means carriers of the different cutter groups lie alternately next to one another so that each cutting means carrier has direct neighbors of the other cutter group, and in the narrower tool body segments (WS-S), there is a pair of cutting means carriers of the same cutter group lying next to one another; a third configuration, in which cutting means carriers of both cutter groups are distributed intermingled over the circumference, wherein in narrower tool body segments (WS-S), cutting means carriers of different cutter groups lie alternately next to one another, and in wider tool body segments (WS-B), two cutting means carriers of the same cutter group are arranged directly next to one another; a fourth configuration, in which within tool body segments between directly adjacent guide strips, cutting means carriers of both cutter groups are arranged alternately next to one another in the circumferential direction.