HONING TOOL AND METHOD FOR PRODUCING A HONING TOOL
20250010423 · 2025-01-09
Assignee
Inventors
- Oliver Bachmann (Frickenhausen, DE)
- Giorgio Iannuzzi (Nürtingen, DE)
- Robert Kapp (Nürtingen, DE)
- Florian Kranichsfeld (Oberboihingen, DE)
- Joachim Weiblen (Metzingen, DE)
Cpc classification
International classification
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.
Claims
1. A honing tool for machining an inner surface 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 which defines a tool axis and has a guide bore coaxial to the tool axis for receiving two axially movable feed elements, and a plurality of guide openings which are distributed over the circumference of the tool body and lead radially relative to the tool axis from the guide bore to an outside of the tool body; a first feed element and a second feed element which are received in the guide bore and are axially movable independently of one another; a plurality of cutting means carriers which each have a carrier portion which is wide in the circumferential direction and has an outside for receiving cutting means, and have a feed portion 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, 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 form a first cutter group, and all cutting means carriers which can be advanced via the second feed element form a second cutter group; wherein: the tool body has fourteen or more guide openings which have an irregular angular division such that one or more of the guide openings has a different angular spacing from the directly adjacent guide openings in the circumferential direction.
2. The honing tool as claimed in claim 1, wherein the number of guide openings is an even number, wherein guide openings lie in pairs diametrically opposite one another relative to the tool axis.
3. The honing tool as claimed in claim 1, wherein the number of guide openings is not divisible by four.
4. The honing tool as claimed in claim 1, wherein the guide openings are distributed over the circumference of the tool body such that there is a two-fold rotational symmetry around the tool axis, but no mirror symmetry relative to a plane containing the tool axis.
5. The honing tool as claimed in claim 1, wherein for a number T of cutting means carriers, one of the cutter groups comprises a number T/21 of cutting means carriers and the other cutter group a number T/2+1 of cutting means carriers.
6. The honing tool as claimed in claim 1, wherein the honing tool has a guide group with multiple non-cutting guide strips which are distributed on the tool body with an irregular angular division over the circumference of the tool body.
7. The honing tool as claimed in claim 6, wherein four non-cutting guide strips 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.
8. The honing tool as claimed in preceding claim 1, wherein the guide openings and/or the cutting means carriers have an axial length which amounts to more than 50% of the maximum effective outer diameter of the honing tool, in particular between 80% and 95% of this outer diameter.
9. The honing tool as claimed in claim 1, wherein carrier portions have on the outsides multiple mutually parallel receiving grooves, each for receiving at least one strip-like cutting means unit.
10. The honing tool as claimed in claim 1, wherein one, several or all receiving grooves are fitted with cutting means units which substantially fill the entire length of a receiving groove.
11. The honing tool as claimed in claim 1, wherein a short strip-like cutting means unit is arranged in the at least one receiving groove.
12. The honing tool as claimed in claim 1, wherein the tool body is equipped according to a configuration 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, cutting means carriers of 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, 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, cutting means carriers of different cutter groups lie alternately next to one another, and in the wider tool body segments, 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. A 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 in production of cylinder blocks or cylinder liners for reciprocating piston engines, with the following steps: provision of a tool body which defines a tool axis and comprises a guide bore coaxial to the tool axis for receiving two mutually independently axially movable feed elements, and a number of fourteen or more guide openings which lead radially relative to the tool axis from the guide bore to an outside of the tool body and are distributed over the circumference with an irregular angular division, such that one or more guide openings have different angular spacings from the directly adjacent guide openings in the circumferential direction; equipping the tool body with cutting means carriers each having a carrier portion which is wide in the circumferential direction and has an outside for receiving cutting means, and have a feed portion 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, 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 and a second feed element by insertion into the feed bore; wherein the cutting means carriers and the feed elements 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. The method as claimed in claim 13, wherein the tool body 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, cutting means carriers of 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, 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, cutting means carriers of different cutter groups lie alternately next to one another, and in the wider tool body segments, 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.
15. The honing tool as claimed in claim 2, wherein identical cutting means carriers of the same cutter group with cutting means provided in identical fashion are arranged at the guide openings diametrically opposite one another.
16. The honing tool as claimed in claim 3, wherein the tool body has precisely fourteen guide openings or precisely eighteen guide openings or precisely twenty-two guide openings.
17. The honing tool as claimed in claim 5, wherein mutually identical cutting means carriers fitted with cutting means of the same cutter group are arranged at the diametrically opposed guide openings.
18. The honing tool as claimed in claim 7, wherein in the tool body segments with the greater circumferential width, there is a number N, and in the tool body segments with smaller circumferential width, there is a number N-1 of guide openings arranged directly next to one another.
19. The honing tool as claimed in claim 1, wherein carrier portions have on the outsides two, three or four mutually parallel receiving grooves, each for receiving at least one strip-like cutting means unit.
20. The honing tool as claimed in claim 11, wherein the cutting means unit has a length which corresponds to less than 50% of the axial length of the carrier portion.
21. The honing tool as claimed in claim 20, wherein 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.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Further advantages and aspects of the invention arise from the claims and the description of exemplary embodiments of the invention which are presented below with reference to the figures.
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0031]
[0032] The honing tool is suitable and intended for machining an inner face of a bore in a workpiece by means of honing, and in the example is configured for honing cylinder run faces in the production of cylinder blocks or cylinder liners for reciprocating piston engines.
[0033] The honing tool is versatile in use and can be prepared or configured for widely varying machining tasks with few manual interventions. The honing tool may e.g. be used in different configurations for machining circular cylindrical bores, i.e. rotationally symmetrical bores without axial contour development. In other configurations, it may be used for machining rotationally symmetrical bores which have bore portions of different diameter and/or different shape, for example bottle-shaped or barrel-shaped bores, and/or bores which have at least one conical bore portion with axially continuously changing diameter.
[0034] The honing tool has a material body 110 made of a steel material and defining a tool axis 112, which simultaneously is the rotational axis of the honing tool during machining. On the spindle-side end of the honing tool is a coupling structure 120 for connecting the honing tool to a drive rod or working spindle of a honing machine, or another machining tool with a working spindle which can both rotate about the spindle axis and also oscillate to and fro parallel to the spindle axis. In
[0035] In the end portion of the tool body facing away from the coupling structure 120 or working spindle (not shown) is the cutting region 130 of the honing tool, in which all abrasive cutting means are arranged (in the form of cutting strips, general reference sign 170). The cutting region 130 is more or less flush with the end of the tool body remote from the spindle and arranged in the end portion of the tool body facing away from the spindle, so that if necessary blind bores can also be machined down to the bore base. Within the cutting region 130, many strip-like cutting means 170 (also referred to below as cutting strips) are distributed around the circumference of the tool body. The length LSB of the cutting region is here between 80% and 95% of the outer diameter AD of the honing tool. In this example, the outer diameter lies in the order of 80 mm; it may e.g. lie in the range from 60 mm to 90 mm but in some cases also above or below this.
[0036] The honing tool 100 has an integrated swivel joint 190 via which the tool body 110 is coupled with limited movability to the connection piece which serves for connection to the working spindle of the machining tool. The joint 180 in this example is configured as a ball joint, wherein the ball 192 is formed at the lower end of the connection piece while the corresponding bearing element with concave spherical bearing surfaces is arranged within the tool body 110. This allows a limited movability of the tool body relative to connection piece in an infinite multiplicity of directions running transversely to the tool axis, whereby the honing tool can particularly closely follow the casing surfaces for machining bore inner faces in order to improve the quality of shape and surface.
[0037] The honing tool 100 in
[0038] The tool body has multiple, axially elongate guide openings (general reference sign 160) which lead radially relative 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 distributed over the circumference with an irregular angular division. An irregular angular division here means that one or more of the guide openings have different angular spacings from the guide openings which lie directly adjacent thereto in the circumferential direction without interposed guide strip.
[0039] On the outside of the tool body, four non-advanceable, non-cutting guide strips 190-1 to 190-4 of a guide group are arranged diametrically opposite one another in pairs. The guide strips are distributed with an irregular angular division, so that tool body segments lying between directly adjacent guide strips in the circumferential direction have different circumferential widths in pairs. These are around 78 for the narrower tool body segments WS-S and around 102 for the wider tool body segments WS-B. The wider tool body segments each hold four, the narrower segments only three guide openings arranged directly adjacent to one another without interposed guide strips. The guide group has a two-fold rotational symmetry relative to the tool axis.
[0040] Two diametrically opposed guide strips 190-1 and 190-3 are designed as measuring strips. In the part of the cutting region furthest away from the coupling, they have a measurement region with three axially mutually offset radial bores 195, which may be used as measuring nozzles of a pneumatic diameter measuring system. To measure in a specific measurement plane, the radial bores lying in this plane are opened and the unused radial bores are closed.
[0041]
[0042] Thus for each of the two middle guide openings 160-13 and 160-14, the angular spacing from the respective two guide openings directly adjacent in the circumferential direction is different. The differences in angular spacing (approximately 1) clearly lie outside production tolerances and are of the order of a few percent (e.g. from 2% to 5%) of the absolute value of the angular spacing. For reasons of symmetry, this irregular angular distribution is also present on the opposite side, i.e. in the other wider tool body segment.
[0043] The guide openings which lie only indirectly next to one another with an interposed guide strip have a respective angular spacing of around 34. Thus the angular distribution of the guide openings over the circumference is characterized by three different values for angular spacing, namely four times around 22, two times around 23 and four times around 34. Thus in this respect, there is an irregular or asymmetric angular division.
[0044] With the honing tool configured ready for use, the tool body 110 carries a plurality of cutting means carriers (general reference sign 150). The cutting means carriers are each one-piece components made of steel material which are substantially rigid. Each cutting means carrier has a carrier portion 152 which is relatively wide in the circumferential direction and on the outside has multiple, preferably two, three or four mutually parallel receiving grooves 156 lying in a common plane for each receiving a strip-like cutting means unit. The circumferential width of the carrier portions here lies in the range from around 15 to around 20.
[0045] On the substantially flat inside of the carrier portion, an initially plate-like then slightly tapering feed portion 158 protrudes towards the inside. On the inside of the feed portion facing away from the outside 154 are sloping faces which cooperate with a corresponding sloping face 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 means carrier. The plate-like part of the feed portion 158 thus sits radially movably in the substantially rectangular guide opening 160 of the tool body, so that a radial movement (relative to the tool axis 112) is possible while tilt movements in the transverse direction thereto are largely prevented. The cutting means carriers are preloaded into the inwardly retracted position by means of two peripheral coil springs, so that the radial feed takes place towards the outside against the force of these return springs.
[0046] In the exemplary embodiment, all cutting means are formed as cutting strips narrow in the circumferential direction, the width BS of which measured in the circumferential direction is small relative to the axial length LS. An aspect ratio between length LS and width BS may for example lie in the 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.
[0047] The honing tool 100 may be configured for different machining tasks without great complexity. For a specific configuration, usually two steps are required. A first step comprises fitting the tool body 110 with cutting means carriers equipped with suitable cutting means. The cutting means carriers are introduced from the outside into the respective guide openings 160 provided for these, with the desired distribution for the two cutter groups.
[0048] To ensure that the cutting means carriers belonging to a cutter group are advanced together during the advance of a feed element while the cutting means carriers of the other group are not advanced, the configuration comprises as a second step the installation of corresponding first and second feed elements. This is relatively easy with the honing tool since, in fitted state, the feed elements are secured against falling out and held in position only by two radially inwardly engaging screws. To exchange the feed elements, the retaining screws are unscrewed and the feed elements withdrawn from the free end face of the tool body. Then feed elements suitable for the desired configuration are inserted in the guide bore 115 and secured against falling out by tightening the retaining screws. There is a first and second feed element for each specific circumferential distribution of cutting means carriers between first and second cutter groups.
[0049] With reference to
[0050]
[0051] Also, the number of receiving grooves 156 of rectangular cross-section on the carrier portions of the cutting means carriers should be noted. In the examples, cutting means carriers with either three or four equidistant receiving grooves of the same dimensions are shown. In all exemplary embodiments illustrated, the cutting means carriers 150 of the first cutter group each have three comparatively wide receiving grooves, while the cutting means carriers of the second cutter group each have four slightly narrower receiving grooves. Other divisions are possible. For example, the same number of receiving grooves (e.g. two, three or four) may be provided everywhere.
[0052] The respective first cutter group comprises six cutting means carriers, while the second cutter group comprises eight cutting means carriers. The number of receiving grooves on the respective cutting means carriers therefore corresponds to half the number of cutting means carriers of a cutter group. In these examples, this division means that for cutting means carriers of the first cutter group, for each carrier unit a larger part of the circumferential width is filled with cutting means than for the cutting means carriers of the second cutter group, where correspondingly a smaller proportion of the circumferential face of the cutting means carriers is filled with cutting means. Thus in all examples, the condition is fulfilled that for the cutting means carriers of the cutter group having fewer cutting outer means carriers, the faces viewed in the circumferential direction are more densely filled with cutting means than for the cutting means carriers of the group with the larger number. The allocation may however also be changed.
[0053]
[0054] If all receiving grooves of the cutting means carriers are filled with cutting means, the first cutter group has 18 cutting strips and the second cutter group 32 cutting strips. However, not all receiving grooves need be filled with cutting means.
[0055] In this example, as in the other examples, the irregular angular division between adjacent cutting means carriers may lead to a reduction in chatter tendency during machining, also to solving overlap problems in so-called spiral honing which uses relatively large honing angles (for example up to the order of) 140.
[0056]
[0057]
[0058]
[0059] As already mentioned, the cutting means carriers may be variably equipped with cutting means of different widths and/or different lengths, and/or with different numbers of cutting means.
[0060]
[0061]
[0062]
[0063]
[0064] The following explanations may be useful for the selection of most suitable configuration, i.e. an arrangement or distribution of the cutting strips well adapted to the machining task.
[0065] Very stable bores (bores without local weaknesses such as e.g. absent stiffening ribs) or cylinder liners can be honed with a shell arrangement (see e.g.
[0066] With an almost fully symmetrical arrangement (see e.g.
[0067] The divisions between the limit cases of shell arrangement (see
[0068] The axial position of the measuring nozzles or measurement plane defined thereby can be adapted to the corresponding requirements. The axial position may be selected so that it lies approximately centrally in the region fitted with cutting means. The honing tool as a production tool can be easily adapted to different machining tasks. It is also very suitable as an experimental tool because of the flexibility of usage types.