Honing tool with honing-stone-restoring system
Patent Information
- Application Number
- EP2023708471
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-03-10
- Filing Date
- 2023-02-28
- Publication Date
- 2025-01-15
AI Technical Summary
Existing honing tools face challenges in reliably resetting honing stones, especially in smaller diameters, where conventional return springs and O-rings are complex, difficult to manufacture, and inefficient in handling and force distribution, particularly when internal coolant is used.
A honing tool with a C-shaped elastic restoring element that encloses the tool body partially, providing easy assembly and disassembly without tools, and generating strong restoring forces to securely hold the honing stone in place, using spring steel or elastomeric materials for effective radial force application.
The C-shaped elastic restoring element ensures reliable and efficient honing stone resetting, maintaining mechanical contact under fluid pressure, preventing hydraulic displacement and enhancing tool handling and operational reliability.
Smart Images
Figure 1.1
Abstract
Description
[0001] Honing tool with honing stone return system
[0002] FIELD OF APPLICATION AND STATE OF THE ART
[0003] The invention relates to a honing tool according to the preamble of claim 1 and to a honing stone usable for producing such a honing tool according to the preamble of claim 10.
[0004] Honing is a machining process with geometrically indeterminate cutting edges, in which a honing tool executes a two-component cutting movement within a bore to be machined, and there is constant surface contact between one or more cutting material bodies of the honing tool and the inner surface of the bore to be machined. The kinematics of an expandable honing tool are characterized by the superposition of a rotary movement, a stroke movement running in the axial direction of the bore, which in most cases is oscillating, and an infeed movement that leads to a change in the effective diameter of the honing tool. A surface structure with intersecting machining marks results on the inner surface of the bore. Surfaces finished by honing can meet high requirements with regard to dimensional and form tolerances, so that many highly stressed sliding surfaces in engines or engine components, e.g.Cylinder running surfaces in engine blocks or bore inner surfaces in injection pump housings are machined by honing.
[0005] Honing tools are used, particularly for machining bores with relatively small diameters, for example, in the diameter range of 15 mm or less. These tools have a tubular tool body, at least in part, which has a cutting area with at least one honing stone receiving opening extending from the inside of the tool body to the outside for receiving a honing stone. The tool body serves as a holder for one or more honing stones and simultaneously as a guide for an infeed element that serves to radially feed the honing stones. The honing tool comprises a device for releasably attaching the honing tool to the work spindle of a honing machine.
[0006] The dimensions of the generally rectangular honing stone receiving opening and the corresponding cross-sectional dimensions of the honing stone are coordinated in such a way that the honing stone is radially movable and, in the circumferential direction of the tool body, is accommodated between the boundary surfaces of the honing stone receiving opening with essentially no play. The attempt is usually made to achieve a sliding fit by precisely machining the boundary surfaces of the honing stone receiving opening and the corresponding side surfaces of the honing stone, so that the honing stone can just barely be inserted into the honing stone receiving opening by hand and is held there by static friction forces between the side surfaces of the honing stone and the adjacent boundary surfaces of the honing stone receiving opening.
[0007] The inner side of the honing stone, which projects into the interior of the tool body, generally has an inclined surface which interacts with a corresponding inclined surface on the feed element in the manner of a wedge drive in such a way that an axial displacement of the feed element towards the end of the tool body remote from the spindle causes a radial displacement of the honing stone outwards.
[0008] Honing stone resetting is also of great importance for honing tools. Honing stone resetting involves a radial inward displacement of the honing stone during an axial displacement of the feed element toward the end of the tool body closest to the spindle. This facilitates the removal of the honing tool from the machined bore and also prevents damage to the honing stone and / or the bore's inner surface. Similar advantages can also arise when inserting the tool into a new bore. Various honing stone resetting systems have been developed to enable the honing stone resetting.
[0009] Hone stone return systems with so-called return springs are well known. These are usually designed as ring-shaped, closed worm springs or helical tension springs. Usually, two return springs are provided, which are inserted into a ring groove machined into the tool body near the axial ends of the honing stones and grip the axial ends of the honing stones. The return springs are intended to ensure that the honing stones are pushed back into the tool body at the end of the machining process when the feed cones retract.
[0010] Instead of return springs, elastic O-rings are sometimes used as return elements for honing tools with smaller diameters.
[0011] TASK AND SOLUTION
[0012] It is an object of the invention to provide a generic honing tool which has a reliably functioning honing stone return system, which can be manufactured with relatively simple design measures and is characterized by easy handling during manufacture and use.
[0013] To achieve these objects, the invention provides a honing tool having the features of claim 1 and a honing stone having the features of claim 10. Advantageous further developments are specified in the dependent claims. The wording of all claims is incorporated into the description by reference.
[0014] A honing tool according to the claimed invention has a tool body that is at least partially tubular and comprises a cutting area with at least one honing stone receiving opening that extends from the interior of the tool body to the outside and serves to accommodate a single honing stone. The dimensions of the honing stone receiving opening and the honing stone in the circumferential direction and preferably also in the axial direction are coordinated such that the honing stone is radially movable and is received between boundary surfaces of the honing stone receiving opening in the circumferential direction of the tool body with essentially no play. The radial mobility ensures that the honing stone can be advanced in the radial direction with the aid of an advance element guided axially displaceably inside the tool body via cooperating inclined surfaces upon axial displacement of the advance element.The honing tool has a honing stone return system comprising at least one elastic return element. When the honing stone is installed, the elastic return element engages the honing stone in such a way that a radial force acts from the outside to the inside, pushing the honing stone toward the feed element.
[0015] A honing tool according to the claimed invention is characterized in that the elastic return element is C-shaped and partially encloses the outer side of the tool body in the circumferential direction. "Partially" here means in particular that the return element does not completely enclose the outer side of the tool body, but leaves a certain circumferential section free. The elastic return element can be attached to the outer side of the tool body with elastic deformation. The partially open, C-shaped configuration ensures, among other things, that the elastic return element is easy to mount on the tool body. When attached, the return element can hold itself to the tool body due to its elasticity. In addition, the elastic return element can be easily removed, especially when changing the honing stone.For assembly, the reset element can be attached to the side of the tool body; for disassembly, it can be removed from the side. "Laterally" refers specifically to a direction perpendicular to the tool axis. No tools are required, especially for assembly and, if necessary, also for disassembly. Pliers, a screwdriver, or a similar tool can be used for simple, convenient disassembly of the reset element. It is easy to handle because a fitter can hold the honing tool in one hand and grasp the reset element with the other hand, then attach or remove it.
[0016] In a further development of the invention, the C-shaped elastic return element has an opening angle of more than 90° and less than 180° in a relaxed state. The opening angle refers to the angle measured in the circumferential direction between the free ends of the C-shape. This represents a structurally and functionally advantageous implementation for the honing stone return system. With an opening angle in this range, the elastic return element is, on the one hand, easy to assemble and disassemble because the C-shape is open over at least a quarter of its circumference; on the other hand, the return element is securely and reliably held or attached to the tool body because it encompasses the workpiece body over more than half of its circumference. The elastic return element can be attached to the tool body by clipping it on from the side, undergoing elastic deformation.When attached, the return element is automatically and permanently attached to the tool body. "Permanent" specifically means that the return element cannot detach or fall off the tool body on its own, e.g., due to gravity.
[0017] When installed, the elastic return element preferably encloses the outer surface of the tool body by more than 180° and less than 270°, in particular by approximately 225°. This represents a structurally and functionally advantageous implementation for the honing stone return system. In this design, the elastic return element is easy to install and remove, while also being securely and reliably held or attached to the tool body.
[0018] In one development of the invention, the elastic return element is a bent wire part, preferably made of spring steel. Bent wire parts can be produced quickly and cost-effectively, and with precisely maintained dimensions. Spring steel is very elastic and, among other things, has a tensile strength and high elongation at break that is ideal for the application. This means that large elastic return forces can be generated during elastic deformation. The elastic return element is designed so that it can bend up to its elastic limit and return to its original shape after the load is removed, without being permanently deformed. Alternatively, a return element can also be manufactured, for example, as a stamped part. In alternative designs, the elastic return element is made of an elastomer material. The elastomer material can have similar material properties to the spring steel.
[0019] The C-shaped return element can essentially have the shape of a circular arc or an elliptical arc with a uniform or only slightly varying curvature up to the ends.
[0020] In a further development of the invention, an end section of the elastic return element facing the honing stone is bent, whereby the return element can be connected to the honing stone via this bent end section. "Connectable" here means in particular that the return element can engage the honing stone for force transmission and is detachably attached to the honing stone. In this embodiment, a further end section of the elastic return element, facing away from the bent end section, encloses the tool body and rests at least partially against it.
[0021] Preferably, the end section of the elastic return element facing the honing stone is bent radially inward. It then lies in the plane defined by the C-shape. In alternative embodiments, the end section of the return element facing the honing stone can be bent, for example, in the axial direction. This means that the bent end section protrudes from the plane defined by the C-shape, in particular essentially perpendicular to it. The bent end section of the return element runs parallel to the tool axis.
[0022] In a further development of the invention, the honing stone comprises a support stone and a cutting coating applied to a radial outer side of the support stone. The cutting coating can be sintered or soldered onto the support stone, for example. The radial outer side of the support stone lies opposite the inclined surface of the support stone. In this embodiment, the elastic return element can be connectable to the support stone. The return element can thus engage in a section not provided with a cutting coating. "Connectable" here also means in particular that the return element is detachably attached to the support stone. This represents a structurally and functionally advantageous implementation for the honing stone return system.
[0023] In a further development of the invention, the honing stone has a recess on its outer side, into which one end of the elastic return element can be hooked. The recess is preferably a radial bore, in particular a blind hole, which is formed in the honing stone in such a way that, when the honing stone is installed, it points in the direction of the tool axis. The recess can provide a locally defined position for force-transmitting contact with the return element and can also serve as a locking recess into which one end of the return element can snap during assembly.
[0024] In alternative designs, the bore on the outside of the honing stone does not run radially, e.g. the bore can run through the honing stone in the circumferential direction of the tool body.
[0025] In a further development of the invention, the elastic return element has an inner diameter which, in a relaxed state, is smaller than the outer diameter of the outer side of the tool body against which the elastic return element at least partially rests. The inner diameter of the elastic return element describes the diameter measured from inner side to inner side, with the inner side facing the tool body when the return element is installed. The outer diameter of the outer side of the tool body corresponds to the diameter measured from outer side to outer side. If the elastic return element is attached to the honing stone inserted in the honing stone receiving opening of the tool body and to the tool body, then even in the returned state or in the initial state of the honing stone, a certain force acts on the honing stone due to the pretension or deformation of the elastic return element.This force has a radial component that acts from the outside inward and presses the honing stone against the feed element. This represents a structurally and functionally advantageous implementation for the honing stone return system.
[0026] In some embodiments, the outer surface of the tool body has an annular groove or ring recess for receiving the elastic return element in the circumferential direction. If this is the case, the inner diameter of the elastic return element in a relaxed state is smaller than the outer diameter of the tool body measured at the groove base.
[0027] In a further development of the invention, the honing tool has at least one fluid supply channel in the tubular tool body for supplying coolant and / or lubricant to the cutting area. The fluid supply channel opens into a cavity which also contains the honing stone and the feed element. The internal coolant supply is particularly advantageous for long bores, as the coolant can be directed very precisely to the cutting area for cooling, lubrication and chip removal. This leads to better surface qualities, stock removal rates, tool life and thermal stabilization of the machining process. The elastic return element and the associated return forces are particularly important for honing tools with an internal fluid supply. This is because the fluid supply creates fluid forces in the cavity which, among other things, also act on the honing stone, in particular the support stone.This sits radially displaceable in its honing stone receiving opening and can be pushed outwards by the fluid pressure similar to a piston and lifted off the feed element.
[0028] The inventor has discovered that this effect is often impossible or difficult to suppress with the restoring forces of conventional worm springs or O-rings. Furthermore, even in the initial position, where the worm springs or O-rings are virtually unable to effect any restoring, high forces can be achieved with the elastic, C-shaped restoring element according to the invention. The restoring forces or the contact forces of the elastic restoring element can be so large that fluid pressure-induced lifting of the honing stone from the feed element is prevented.
[0029] In alternative designs, the coolant and / or lubricant are supplied exclusively from the outside or from both the outside and inside. Alternatively, honing can be performed dry, without coolant and / or lubricant.
[0030] In a further development of the invention, the honing tool is a single-stone honing tool, i.e., it has only a single honing stone. Two guide stones made of hard metal, sintered metal, or another hard material, such as ceramic, can be attached to the outer side of the tool body opposite the honing stone receiving opening. They can be circumferentially offset by approximately 90°, for example. If only a single honing stone is present, attaching the return element is particularly simple.
[0031] In some embodiments, the honing stone return system has two elastic return elements per honing stone. The elastic return elements can be connected or attached to the honing stone at one axial end area each. This creates a uniform return force distribution in the axial direction, which counteracts unwanted tilting of the honing stone. The two elastic return elements can be attached from the same side or from two opposite sides.
[0032] The honing tool can also be a multi-stone honing tool. In these cases, the honing stone return system can have several axially offset return elements in each axial end region of the cutting area equipped with honing stones. Particularly preferred are embodiments in which the outer side of the tool body, in particular at an axial end region of the honing stone receiving opening, has an annular groove in the circumferential direction for receiving the elastic return element.
[0033] The honing stone according to the invention is suitable and intended for use in a honing tool having a tool body that is at least partially tubular and has a cutting area with at least one honing stone receiving opening extending from the interior of the tool body to the outside for receiving a honing stone. The dimensions of the honing stone and the dimensions of the honing stone receiving opening are coordinated such that the honing stone is radially movable and can be received in the circumferential direction of the tool body essentially without play between boundary surfaces of the honing stone receiving opening and has an inclined surface on an inner side projecting into the interior of the tool body.
[0034] A honing stone according to the claimed invention is characterized in that the honing stone has a recess, in particular a radial bore, on an outer side. Preferably, such a recess is formed at each end section of the support stone in extension of the elongated cutting surface. The honing stone is thus particularly adapted for interaction with a honing tool of the type described here, which has a honing stone return system with an elastic, C-shaped return element. In this case, the return element is configured, when the honing stone is installed, to partially enclose an outer side of the tool body in the circumferential direction and to engage therewith with a pressing force generated by expansion such that the honing stone is held in the honing stone receiving opening. An inwardly bent end section of the C-shaped return element can engage in the recess.
[0035] Existing honing tools (new or previously used) can be easily converted to utilize the advantages of the invention. For this purpose, the invention also provides a retrofit kit comprising at least one honing stone of the type mentioned above and a suitable number of matching C-shaped return elements, for example, two, three, four, five, six, or more per honing stone.
[0036] BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Further advantages and aspects of the invention emerge from the claims and from the description of exemplary embodiments of the invention, which are explained below with reference to the figures. Fig. 1 shows a longitudinal section of a honing tool according to one embodiment;
[0038] Fig. 2 shows a cross section of the honing tool along a line ll-ll of Fig. 1;
[0039] Fig. 3 shows a cross section of the honing tool along a line III-III of Fig. 1;
[0040] Fig. 4 shows a section of a longitudinal section of the honing tool along a line IV-IV of Fig. 3;
[0041] Fig. 5 shows a section of a longitudinal section of the honing tool along a line VV of Fig. 3;
[0042] Fig. 6 shows an oblique perspective view of the free end portion of the honing tool of Fig. 1.
[0043] DETAILED DESCRIPTION OF THE EMBODIMENTS
[0044] Fig. 1 shows a longitudinal section through an embodiment of a honing tool 100 parallel to the tool axis (rotation axis) 101 of the honing tool 100. Figs. 2 and 3 show a cross-section orthogonal to the tool axis 101 of the honing tool 100 from Fig. 1. Figs. 4 and 5 show a section of a longitudinal section of the honing tool 100 from Fig. 1. Fig. 6 shows a section of an oblique perspective view of the honing tool 100 from Fig. 1.
[0045] The honing tool 100 is designed as a single-stone honing tool, i.e., it has only a single radially adjustable honing stone 200 in its cutting area. The honing tool 100 has a tool body 110 that has approximately the shape of a tube open on both sides with a relatively large wall thickness, wherein the outer diameter of the tube varies in sections in the axial direction.
[0046] The end section 180 of the tool body 110, shown on the right in Fig. 1, serves to couple the honing tool 100 to the work spindle of a machine tool, in particular a honing machine. Located in the opposite free end section of the tool body is the cutting area of the honing tool 100, which is inserted into the interior of a bore to be machined for honing. In the cutting area, the tool body 110 has a rectangular honing stone receiving opening 120 extending from the interior of the tool body 100 to the outside, in which a honing stone 200 is precisely accommodated when the honing tool 100 is assembled. The axial length of the honing stone receiving opening 120 is a multiple of the width measured in the circumferential direction.
[0047] The honing stone receiving opening 120 is defined by four pairs of parallel, flat boundary surfaces. Parallel to the axial direction, two flat boundary surfaces acting in the circumferential direction are provided, namely a first boundary surface 121 and a second boundary surface 122 parallel thereto. The boundary surfaces 121, 122 are each flat and run parallel to a plane spanned by the tool axis 101 and a radial direction running centrally between the lateral boundary surfaces 121, 122. In the axial direction, the honing stone receiving opening 120 is defined by an upper boundary surface and a lower boundary surface, each of which lies in a plane normal to the tool axis 101.
[0048] On the side opposite the honing stone receiving opening 120, two guide rails 160, 170 made of hard metal, sintered metal, or another hard material, such as ceramic, are mounted on the tool, circumferentially offset by approximately 90°. These guide rails rest with their smoothly polished, curved outer surfaces against the inner wall of the bore to be honed. The guide rails can be coated, for example, with diamond, to form a wear-resistant outer surface.
[0049] The honing stone 200 is plate-shaped overall and has a plate-shaped support bar 210 made of steel. A cutting coating 220 containing the cutting material grains bound in a bond is applied to the radial outer side 212 of the support bar 210. The cutting coating 220 can be sintered directly onto the flat outer side of the support bar 210, but it can also be glued or soldered, or attached to the support bar 210 by rivets or screws. It is also possible for a flat base 222 supporting the cutting coating 220 to be located between the cutting coating 220 and the support bar 210.
[0050] On the radial inner side of the support bar 210, a flat inclined surface 211 is formed, which interacts with a complementary flat inclined surface 131 at the lower end of an infeed element 130 guided in the tool body 110 in the manner of a wedge drive such that the honing stone 200 is pressed radially outward within the honing stone receiving opening 120 when the infeed element 130 is pressed in the direction of the cutting area of the honing tool 100 by the infeed drive accommodated in the honing machine 100.
[0051] The dimensions of the honing stone 200 and the honing stone receiving opening 120 are coordinated such that the honing stone 200 is radially movable, but is accommodated between the lateral boundary surfaces 121, 122 in the circumferential direction of the tool body 110, essentially without play. In the axial direction, i.e., between the upper and lower boundary surfaces, a slight play may be present, although a play-free fit is also provided here, if possible.
[0052] During the manufacture of the honing stone 200 and the tool body 110, care is taken to ensure that the clear distance between the front and rear boundary surfaces 121, 122 of the honing stone receiving opening 120 is only minimally larger than the width of the honing stone 200 measured between a front side surface 201 and a rear side surface 202 of the honing stone 200 or the support bar 210. In the best case, a relatively tight sliding fit should result, so that the honing stone 200 can be manually pressed into the honing stone receiving opening 120 from the outside during assembly, but cannot fall out of the honing stone receiving opening 120 on its own. The honing stone 200 should, however, be able to be displaced radially outwards under the action of the feed element 130 pressed downwards.
[0053] The honing tool can be used with internal coolant. Internal coolant is particularly advantageous for long bores, as the coolant can be directed precisely to the cutting edge for cooling, lubrication, and chip removal. This leads to improved surface finishes, stock removal rates, tool life, and thermal stabilization of the machining process.
[0054] To enable internal coolant supply, the honing tool 100 has at least one fluid supply channel 140 in the tubular tool body 110 for supplying coolant and / or lubricant to the cutting area. The fluid supply channel 140 opens into a cavity 150, which also houses the honing stone 200 and the feed element 130. The coolant and / or lubricant passes from the cavity 150 into the cutting area via two radial bores 141, 142 on an outer side 113 of the tool body 110 and an axial bore 143 on an end face 114 of the tool body 110, as shown in Fig. 5.
[0055] With internal fluid supply, fluid forces can be generated in the cavity 150, which, among other things, also act on the support bar 210 of the honing bar 200 and act on it radially outwards.
[0056] It has been shown that, particularly when using an internal coolant supply, which is routed inside the tool body to the exit hole at the point of engagement of the honing stone, the coolant pressure can be sufficient to lift the stone from the cone or the inclined surface of the feed element at exposed points, thereby generating a "hydraulic" feed force across the entire back surface. This is impossible or difficult to suppress with the restoring forces of conventional worm springs or O-rings.
[0057] To avoid such problems, the honing tool 100 is equipped with a honing stone return system 300 which, when the honing stone 200 is installed, acts on the honing stone 200 in such a way that a radial force acts from the outside to the inside and presses the honing stone 200 in the direction of the feed element 130.
[0058] In the illustrated embodiment, the honing stone return system 300 has two elastic, C-shaped return elements 310 of identical configuration, which are explained in more detail below with reference to the return element 310. An elastic return element 310 is attached to each of the two axial end regions 203, 204 of the honing stone 200.
[0059] An elastic return element 310 is a bent wire part made of spring steel. Spring steel has favorable properties for this application, among other things because large elastic restoring forces can be generated upon elastic deformation of the elastic return element 310. The spring steel can, for example, have a strength between approximately 600 and 1800 N / mm 2The elastic return element 310, made from a round wire, essentially has the shape of a non-closed circular arc with a radially inwardly bent end portion 311. In alternative embodiments, the elastic return element 310 can also be made from a profile wire that is not round in cross-section, but rather, for example, polygonal.
[0060] The non-closed circular arc section of the elastic return element 310 defines an opening angle α, wherein the center of the elastic return element 310 is the apex of the opening angle α. The first leg of the opening angle α runs from the apex to a center axis of the radially inwardly bent end section 311 of the elastic return element 310, and the second leg of the opening angle α runs from the apex to an end point at the other end section 312 of the elastic return element 310. When the elastic return element 310 is inserted into the honing stone 200 or on the tool body 110, the opening angle α increases due to the deformation of the elastic return element 310, wherein the first leg also runs through the center axis of the radial bore 231.
[0061] The radially inwardly bent end portion 311 of the elastic return element 310 preferably has a length that can be between 10% and 40% of the outer diameter of the elastic return element 310 and / or between one and three times the wire diameter or the wire thickness of the elastic return element 310. The wire diameter or the wire thickness of the elastic return element 310 can, for example, be in the range between 5% and 20% of the diameter of the tool body 110.
[0062] The tool body 110 further has an annular groove 112 for each elastic return element 310, which is formed on the outer side 113 of the tool body 110. The groove 112 runs over the entire circumference of the tool body 110 and can be produced, for example, by turning. An annular groove 112 runs along each axial end region 203, 204 of the honing stone 200 or honing stone receiving opening 120. Furthermore, a groove runs along the radial outer side 212 of each cutting-coating-free end section 213, 214 of the support bar 210, which groove extends in the returned state of the honing stone 200 as an extension of the annular groove 112. Alternatively, the radial outer side 212 of the cutting-coating-free end section 213, 214 of the support bar 210 can have a shoulder. The cutting-coat-free end sections 213, 214 of the support bar 210 each have a radial bore 231 in this groove.The radial bore 231 is introduced into the support bar 210 in such a way that, when the honing bar 200 is installed, it points in the direction of the tool axis 101.
[0063] Fig. 2 shows a section through the honing tool 100, directed orthogonally to the tool axis 101, in the region of the annular groove 112 and the radial bore 231 along the section line 11-11 in Fig. 1.
[0064] The arrangement of the elastic return element 310 on the tool body 110 is described below. The same applies to the second elastic return element 310.
[0065] The elastic return element 310 is arranged or suspended in the radial bore 231 with its radially inwardly bent end section 311, and partially encloses an outer side or a groove base 111 of the annular groove 112 in the circumferential direction with the C-shaped part. The elastic return element 310 has an inner diameter that, in a relaxed state, is smaller than the outer diameter of the annular groove 112 measured at the groove base 111.
[0066] To assemble the return element 310, the bent end section 311 of the elastic return element 310 is inserted into the radial bore 231, and while elastically deforming the elastic return element 310, the other end section 312 of the elastic return element 310 is placed or attached in the annular groove 112 around the tool body 110. The partially open, C-shaped configuration of the elastic return element 310 makes it easy to mount it on the tool body 110. When pushed sideways, the C-shape temporarily expands elastically until the return element is then clipped onto the circumference and held to the tool body under elastic clamping force.
[0067] In the illustrated embodiment, the elastic return element 310, in the assembled state, encloses the outer side 111 of the annular groove 112 or the tool body 110 by approximately 225°, thus leaving a certain circumferential section free (see Fig. 2). In the relaxed state, the elastic return element 310 has an opening angle a of slightly less than 135°. This makes the elastic return element 310 easy to assemble and disassemble.
[0068] Due to the elastic preload of the clipped-on return element, a certain force acts on the honing stone 200 in the returned state or initial state of the honing stone 200 due to the deformation or elasticity of the elastic return element 310, which acts from the outside inward and presses the honing stone 200 against the feed element 130. Furthermore, the elastic return element 310 automatically holds itself to the tool body 110 in the attached state.
[0069] Due to the higher restoring forces, which primarily act directly in the radial direction, it is now possible to prevent any "hydraulic" advance of the honing stone 200, since the mechanical contact between the inclined surface 211 or the back surface of the support stone 210 and the inclined surface 131 or the expansion cone of the advance element 130 remains intact and is not hydraulically eroded. This mechanical contact between the honing stone 200 and the advance element 130 would often not be maintained or would be difficult to maintain if conventional worm springs were used as the return element 310 due to their low return forces.
[0070] As the embodiments shown and the other embodiments mentioned above make clear, the invention provides a honing tool and a honing stone which can be used to produce such a honing tool and which offers advantages over conventional honing tools and honing stones, in particular with regard to functionality, operational reliability, structure and / or handling.
Claims
Patent claims honing tool (100) comprising - a tool body (110) that is at least partially tubular and has a cutting area with at least one honing strip receiving opening (120) extending from the interior of the tool body (110) to the outside for receiving a honing strip (200), - wherein the dimensions of the honing stone receiving opening (120) and the honing stone (200) are matched to each other in such a way that the honing stone (200) is radially movable and is received in the circumferential direction of the tool body (110) essentially without play between limiting surfaces (121, 122) of the honing stone receiving opening (120), and - wherein the honing bar (200) has an inclined surface (211) on an inner side projecting into the interior of the tool body (110), - a feed element (130) guided in the tool body (110), which has an inclined surface (131) corresponding to the inclined surface (211) of the honing stone, such that an axial displacement of the feed element (130) to the spindle-remote end of the tool body (110) causes a radial displacement of the honing stone (200) outwards, - a honing stone retraction system (300) comprising at least one elastic retraction element (310) which, in the installed state of the honing stone (200), engages the honing stone (200) such that a radial force acts from the outside inwards and presses the honing stone (200) in the direction of the feed element (130), characterized in that the elastic retraction element (310) is C-shaped and partially encloses an outer surface (111) of the tool body (110) in the circumferential direction. Honing tool (100) according to claim 1, further characterized in that - the elastic return element (310) surrounds the outer surface (111) of the tool body (110) by more than 180° and less than 270°, in particular by about 225°, and / or - the elastic return element (310) has an opening angle of more than 90° and less than 180° in a relaxed state. Honing tool (100) according to claim 1 or 2, further characterized in that - the elastic restoring element (310) is a wire bending part, wherein the wire bending part preferably consists of a spring steel. Honing tool (100) according to one of the preceding claims, further characterized in that - an end section (311) of the elastic return element (310) facing the honing stone (200) is bent, preferably radially inwards, wherein the elastic return element (310) can be connected to the honing stone (200) via this bent end section (311). Honing tool (100) according to one of the preceding claims, further characterized in that - the honing strip (200) has a support strip (210) and a cutting lining (220) applied to a radial outer surface (212) of the support strip (210), and - the elastic return element (310) is connectable to the support bar (210). Honing tool (100) according to one of the preceding claims, further characterized in that - the honing stone (200) has a recess (230), preferably a radial bore (231), on an outer side, into which an end of the elastic return element (310) can be hooked. Honing tool (100) according to one of the preceding claims, further characterized in that - the elastic return element (310) has an inner diameter which, in a relaxed state, is smaller than the outer diameter of the outer surface (111) of the tool body (110) against which the elastic return element (310) rests. Honing tool (100) according to one of the preceding claims, further characterized in that - the honing tool (100) has at least one fluid supply channel (140) in the tubular tool body (110) for supplying coolant and / or lubricant to the cutting area, wherein the fluid supply channel (140) opens into a cavity (150) in which the honing stone (200) and the feed element (130) are also located. Honing tool (100) according to one of the preceding claims, further characterized in that - the honing tool (100) is a single-bar honing tool. Honing strip (200) for use in a honing tool (100) which has a tool body (110) that is at least partially tubular and has a cutting area with at least one honing strip receiving opening (120) extending from the interior of the tool body (110) to the outside for receiving a honing strip (200), - wherein the dimensions of the honing stone (200) and the dimensions of the honing stone receiving opening (120) are coordinated such that the honing stone (200) is radially movable and can be received in the circumferential direction of the tool body (110) essentially without play between the limiting surfaces of the honing stone receiving opening (120), and - wherein the honing bar (200) has an inclined surface (210) on an inner side projecting into the interior of the tool body (110), characterized in that - the honing bar (200) has a recess (230), in particular a radial bore (231), on an outer side for receiving a bent end section (311) of an elastic, C-shaped return element (310), - wherein the elastic return element (310) is configured to partially enclose an outer surface of the tool body (110) in the circumferential direction when the honing strip (200) is installed, and to act on this surface with a pressing force generated by expansion such that the honing strip (200) is held in the honing strip receiving opening (120).Retrofit kit for manufacturing a honing tool (100) according to one of claims 1 to 9, comprising: at least one honing bar (200) according to claim 10, which fits into a honing bar opening in a tool body (110) of the honing tool (100); a number of C-shaped elastic return elements (310) which are adapted to the honing bar (200) and the tool body (110) such that a C-shaped return element can be mounted on the tool body by clipping it on and, in the mounted state, partially encloses an outer surface (111) of the tool body (110) in the circumferential direction and engages the honing bar (200) such that a radial force acts from the outside to the inside.