Tool System with Tool Components for Configuring Honing Tools and Manufacturing Process

The present application claims priority to German Patent Application No. 102024110727.8, filed Apr. 17, 2024, the entirety of which is incorporated herein by reference.

The invention relates to a tool system with tool components for configuring honing tools of different effective diameter ranges, as well as to a method for manufacturing a honing tool.

Honing is a cutting method with geometrically undefined cutting edges. During a honing operation, a honing tool is moved up and down or back and forth within the bore to be machined to generate a reciprocating movement in the axial direction of the bore and at the same time to generate a rotating movement superimposed on the reciprocating movement. The cutting coatings attached to the honing tool are pressed against the inner surface to be machined via a feed system with an applied feed force. As a result, the inner surface usually develops a cross-hatch pattern characteristic of honing during the honing process, with mutually intersecting machining marks that are also referred to as “honing grooves”.

Honing tools are available for a wide variety of different machining applications. While the machining of bores with relatively small or medium diameters (e.g. in the diameter range of approx. 1 mm to approx. 100 mm) frequently involves the use of honing tools that are fully pre-assembled by the manufacturer and may only cover a relatively narrow range of effective diameters, in the area of the machining of larger diameters, in particular, concepts with modular tool systems are also available that allow users to configure their own honing tools with the help of mutually coordinated tool components of a tool system, said honing tools being optimised for the intended machining application.

Various manufacturers offer modular tool systems of this kind. One example is described on the website of the manufacturer Delapena at https://delapena.co.uk/honing-tooling/. The honing tools that can be configured using this system cover a total diameter range of 108 mm to 1222 mm and use the manufacturer's standard components. A honing head, which consists of an elongate, rectangular tool body, fits directly onto the drive shaft of the machining machine and has a universal joint and a rotary expansion system. A toothed expansion bar is housed in an axial bore of the tool body for this purpose, acting as a feed element. The tool body has multiple transverse bores oriented perpendicular to the tool axis, each designed to receive a guide pin of a support rail unit. The transverse bores are open to the axial bore, so that, when the honing tool is assembled, the guide pins can establish a force-transmitting contact with the feed element arranged in the axial bore. The transverse bores form multiple groups of bores distributed around the circumference of the tool body, each group having two transverse bores which are axially spaced apart from one another. The tool components also include multiple sets of support rail units. The support rail units to be attached to the tool body each have two axially parallel guide pins on the side to face the tool body, which guide pins are also toothed. By means of interlocking teeth and the corresponding rotation of the toothed expansion bar, the installed support rail units are moved outwards or inwards. The support rail units that fit a tool body only differ in the length of the guide pins and allow the user to cover a specific effective diameter range using one and the same tool body and a corresponding set of support rail units. For larger bore diameters, the assembly described above (tool body with an installed feed element and inserted support rail units) is reinforced by installing a carrier bracket which provides additional rigidity.

However, assembling a modular honing tool of this kind from tool components of the tool system proves to be relatively time-consuming, as the structure is relatively complex. Honing require tools also a relatively long preparation time. In addition, honing tests frequently show significant noise generation and a tendency to develop vibrations that can also lead to compromised quality of the honed surfaces if they exceed certain strength.

The invention is based on the object of providing a tool system with tool components for configuring honing tools, wherein honing tools can be assembled using a relatively small number of different tool components that cover a relatively wide range of effective diameters. The honing tools assembled using the tool components of the tool system should ensure smooth honing operation even at large effective diameters, preventing vibrations that could negatively impact the honing result, so that honing processes can be performed reliably, producing high-quality honed surfaces. Furthermore, the manufacture of the tool components should be cost-effective and resource-efficient and the assembly process should be quick and reliable, even for inexperienced users.

To achieve these objects, the invention provides a tool system with the features of claim. Furthermore, a method for manufacturing a honing tool with the features of claimis provided. Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated by reference to the content of the description.

A tool system according to the claimed invention comprises tool components for configuring honing tools of different effective diameter ranges. In this case, the term “effective diameter” refers to the minimum diameter of a cylindrical envelope that encloses the abrasive cutting surfaces of the honing stones at a given radial feed position. The effective diameter can be varied within the structural and technological limits of the design by means of the feed system. This therefore means that the honing tool is expandable or adjustable in diameter.

The tool components include at least one tool body that defines a tool axis. The tool body forms the basis for assembling a honing tool. The tool axis in this case corresponds to the axis about which the honing tool is intended to rotate during its rotational movement as part of a honing operation. At one machine-side end of the tool body, coupling structures can be provided that allow the attachment of the honing tool to an adapter, a drive rod or a tool spindle of a machining machine.

The tool body contains an axial bore arranged coaxially to the tool axis to receive a (tool-internal) feed element of a feed system. With the help of the feed system, the current effective diameter of the honing tool can be adjusted during operation via the machining machine. The honing tool is therefore an expandable or adjustable honing tool, preferably with a continuously variable effective diameter.

Furthermore, multiple transverse bores oriented perpendicular to the tool axis are provided in the tool body, said transverse bores being open to the axial bore and each designed to receive a guide pin of a support rail unit introduced therein. The transverse bores form multiple groups of bores distributed around the circumference of the tool body, each group having at least two transverse bores which are axially spaced apart from one another. An even number of bore groups evenly distributed around the circumference is preferably provided, for example four bore groups can be provided each offset at 90° intervals around the circumference. Other divisions are possible, e.g. with three or five or six or seven or eight bore groups which may be evenly or unevenly distributed around the circumference.

The tool system also comprises a large number of support rail units that fit the tool body or can be used on the tool body. Each support rail unit has a support rail which has, on an inner side facing the tool body, at least two guide pins that can be inserted into the transverse bores of a bore group and, on an opposite outer side, is designed to support at least one honing stone.

In the case of the support rail units that fit the tool body, the axial spacing of the guide pins corresponds to the axial spacing of the associated transverse bores of a bore group. A tool body of the tool system includes two or more sets of support rail units. The components of the tool system therefore comprise a first set of support rail units and at least one second set of support rail units. Each set of support rail units comprises a number of support rail units corresponding to the number of bore groups, which support rail units are preferably nominally identical to one another. In this case, the support rail units of the first set have first guide pins with a first length and the support rail units of the second set have second guide pins with a second length, wherein the second length is greater than the first length.

Support rail units from different sets therefore differ at least in terms of the length of the guide pins, so that by selecting an appropriate set of support rail units, it is possible to determine which effective diameter range a honing tool can cover.

During the assembly of the honing tool, the support rail units of a set are distributed around the circumference of the tool body and attached thereto by introducing the guide pins provided on the support rails into the transverse bores of the tool body provided therefor. Once the feed element has been introduced into the axial bore, they are in mechanical force-transmitting contact therewith, so that a working movement of the feed element causes an advancing movement of the support rail units.

If the support rail units of the set with the shortest guide pins are used, then, when the support rail units are fully retracted, the lower limit diameter of the associated effective diameter range can be set. If, on the other hand, the support rail units of the set with the longest guide pins are used with the tool body unchanged, the upper limit of the effective diameter range that can be achieved with the same tool body can be reached.

A distinctive feature of the tool system is that the tool system comprises at least one set of bolt guide elements assigned to the tool body which are designed for mounting on or fastening to the tool body, wherein a set of bolt guide elements has a bolt guide element with a guide bore formed therein for each of the transverse bores intended to receive a guide pin, which guide bore runs coaxially with the transverse bores when the bolt guide element is fixedly mounted on the tool body,

The number of bolt guide elements preferably corresponds at least to the number of transverse bores, so that a bolt guide element is available for each of the transverse bores. However, it is possible that not all transverse bores are used. For example, it may be that a support rail unit only has two guide pins, even though a bore group has three transverse bores that can, in principle, be used. The number of guide pins is appropriately defined depending on the length of the honing stones, in order to ensure stability and process reliability.

The bolt guide elements are tool components of the tool system that can be manufactured separately from the tool body and kept available and that can be fastened to a tool body where necessary, in order to achieve more stable guidance when using longer guide pins.

Bolt guide elements can be configured in such a manner that the connection to the tool body is structurally detachable or that the bolt guide elements can be easily produced by the end user, for example, and detached again if necessary, without damaging the tool body or the bolt guide element. A screw connection may be provided for this purpose. It is also possible to attach or fasten bolt guide elements to a tool body in such a manner that they remain permanently on the tool body. A tool body can then be extended by means of the bolt guide element, so that a multi-part modified tool body unit is created by attaching the bolt guide elements based on a tool body.

A bolt guide element fastened to the tool body provides a mechanically stable and load-bearing bolt guide with its guide bore, which bolt guide is positioned at a greater distance from the tool axis than the associated transverse bore in the tool body.

With the help of the components of a set of bolt guide elements of this kind, it can be achieved that, when using the same tool body, not only the effective diameter range that results when using the “bare” tool body (without bolt guide elements fastened thereto) can be covered, but also that support rail units with even longer guide pins can be used, without instability occurring due to an excessively large free length of the extended guide pins when the corresponding support rail unit is fully extended. This allows the available effective diameter range of honing tools that can be built using one and the same type of tool body to be extended towards larger effective diameters, without this resulting in instabilities in the honing tool that could lead to critical vibrations and other disturbances.

As a result, compared with the prior art a significantly vibration-reduced and noise-reduced honing process is achieved across the entire available total effective diameter range, including for larger effective diameters. At the same time, the number of different tool bodies required to cover a given total effective diameter range can be reduced. Whereas traditionally a relatively fine gradation of differently dimensioned tool bodies and, if additional necessary, components for reinforcement or stiffening were therefore required to completely cover a given total effective diameter range, the required number of tool bodies of different dimensions can be reduced due to the provision of the bolt guide elements, as at least two different guiding functions can be realized in the region of the transverse bores with one and the same tool body.

It is possible that the guide bores in the bolt guide elements have the same diameter as the associated transverse bores. It can thereby be ensured that the effective guiding length for the guide pins is extended outwards in such a manner that a guide pin is guided both in the transverse bore and in the guide bore adjacent thereto.

According to one development, it is instead provided that the diameter of the first guide pins (i.e. the first diameter) is adapted to the diameter of the transverse bores in the tool body in such a manner that a sliding guide of the first guide pins can be produced or is formed in the transverse bores of the tool body, and that the diameter of the second guide pins (second diameter) is smaller than the first diameter and is adapted to the diameter of the guide bore of a bolt guide element in such a manner that a sliding guide of the second guide pins can be produced or is formed in the respective bolt guide elements. With this solution, the second guide pins, which are longer than the first guide pins, are guided only in the region of the guide bores of the bolt guide elements, while they sit with play in the associated transverse bores, but are not guided there. With this design, the guidance of the longer second guide pins takes place only in the region of the bolt guide elements attached to the tool body and is thereby shifted outwards in relation to the tool axis. In this embodiment, no constraint forces are exerted on the guided second guide pins, so that jamming of the second guide pins is systematically avoided, thereby ensuring a permanently smooth and reliable guidance of the longer second guide pins. By shifting the effective guidance outwards, it can be achieved that the maximum cantilever length of the longer guide pins during the feed of the support rail units remains relatively short, so that the lever effect under the influence of machining forces is also limited and sufficient mobility of the second guide pins for the feed is always maintained. The diameter differences between the short and longer guide pins can be small and may, for example, be in the range of approx. 500 μm to approx. 1000 μm. It may be that the diameter differences are not perceptible to the naked eye upon casual inspection.

There are different possible ways of providing the bolt guide elements for mounting on the tool body. According to one development, (at least) one elongated guide holder is provided for each of the bore groups, which guide holder has a number of bolt guide elements corresponding to the number of transverse bores in a bore group, with the bolt guide elements being interconnected. In particular, it may be a one-piece component, i.e. made from a single piece of material. Guide holders of this kind offer, among other things, the advantage that the axial distances between the guide bores provided in the guide holder can be maintained with high positional accuracy during manufacturing, so that when an elongate guide holder is attached to the tool body, each of the guide bores formed in the guide holder can be precisely aligned coaxially with the associated transverse bore in the tool body within the limits of small manufacturing tolerances.

According to one development, it is provided that a guide holder has mounting structures for establishing a detachable connection to the tool body. This makes it possible for one and the same tool body or one and the same type of tool body to be used for at least two different diameter ranges. For the smaller diameter range, which comprises the lower limit of the total effective diameter range, the tool body is used without the guide holders attached thereto. If a larger effective diameter range is to be used, the guide holders are attached to the tool body and the support rail units with the longer guide pins (second support rail units) are used.

It is possible to assign only one set of guide holders to a tool body, so that only exactly two different effective diameter ranges can be used. However, it is also possible to assign at least two sets of guide holders to a tool body which have guide bores of different lengths. In this case, it is also possible, in combination with at least three sets of support rails of different guide pin lengths, to realize at least three different effective diameter ranges with one and the same tool body.

In other embodiments, it is provided that a set of bolt guide elements has a separate column-like extension piece for each of the transverse bores, which extension piece is also referred to in this application as a “guide column.” The length of a guide column of this kind, measured parallel to the guide bore contained therein, is preferably greater than the diameter of the guide bore contained therein.

It is possible to adapt the bolt guide elements of a set and the corresponding tool bodies to one another in such a way that the bolt guide elements can be attached to, or removed from, the tool body as required. For this purpose, screw connections or the like can be provided. It is also possible to use sets of bolt guide elements to prepare two or more basic components or multi-part tool body units for different effective diameters based on one and the same type of tool body at the manufacturing stage, by permanently attaching the corresponding bolt guide elements to a tool body, for example, by welding, soldering, gluing or similar means.

A permanent connection of this kind between the tool body and the bolt guide elements may also be provided when the bolt guide elements are grouped into guide holders.

The possible ways of improving the guidance of feed movements in support rail units with guide pins of different lengths, as described, can be implemented in connection with different feed system concepts. For example, it is possible to use this technological approach to optimize tool systems of the kind referred to above (with feed systems utilizing a rack and toothed guide pins).

In preferred embodiments, however, it is provided that the transverse bores are designed as radial bores oriented radially to the tool axis. This results in, among other things, improved force distribution within the honing tool when the support rail units are fed during operation.

According to one development, it is provided that the feed element has multiple, i.e. two, three or more axially offset conical sections with inclined surfaces, and that the guide pins have complementary inclined surfaces at their free ends. This makes it possible for an axial movement of the feed element within the axial bore to be converted via the inclined surfaces in contact with one another into a radial movement of the guide pins or the support rail units. The inventors assume that kind this of contributes feed to significantly reducing the tendency of the honing tools to vibrate in operation, compared with the conventional honing tools referred to above.

Many machining machines are designed for the use of the conventional honing tools referred to above, in such a manner that the machine-side components of the feed system are configured to rotate the feed element mounted in the tool body about the tool axis. To enable honing tools or tool bodies of the kind described here (with an axially movable feed element) to be used on machining machines of this kind too without modification, preferred embodiments provide that the feed element has an axial bore with an internal thread at a machine-side end section and that means are provided to secure the feed element against rotation within the axial guide opening. This ensures that the honing tool can be connected to conventional systems or is compatible with drive elements of existing systems, as the feed system can operate with rotational expansion.

The previously described embodiments of tool systems of the type described for the first time in this application offer, among other things, the advantage that the total available effective diameter range can be extended without increasing the weight of the honing tool to a comparable extent. In some embodiments, specific measures are also provided on the tool body, in order to support weight optimization without limiting functionality.

In some embodiments, the tool body is a one-piece component that alternates in the axial direction between tube sections with a substantially constant wall thickness in the circumferential direction and transverse bore sections containing transverse bores lying therebetween, wherein in the transverse bore sections, each of the transverse bores is has an outwardly projecting column section, in such a manner that the bore length of the transverse bores is greater than a medium wall thickness in the tube sections, in particular at least 20%, or at least 30%, or at least 40% greater, and possibly even about twice as large. This structural approach results in a weight-optimized design, in which outwardly projecting tool body sections are provided only where relatively long guide bores are required on the tool body.

The column sections share the characteristic that the transverse bores of the tool body are arranged within them. The outer shape of the column sections may vary. In many embodiments, the column sections have a substantially sleeve-shaped design, resulting in a cylindrical outer shape, and the transverse bore is partially guided within a sleeve projecting outwards from the tool body. However, a column section may also have a rectangular outer contour. This makes it particularly easy to produce precision surfaces on the tool body that serve as a contact surface for bolt guide elements to be attached to the tool body (individual guide columns or integrated into the guide holder).

The tool system already offers a wide range of different applications due to the previously described tool components. The flexibility of its usability is further enhanced, according to one development, by the fact that the tool components comprise a plurality of interchangeable units that can be mounted interchangeably on a support rail of a support rail unit and each have a rail-shaped adapter plate, which has on one side receiving structures for receiving at least one honing stone and has on an opposite mounting side connecting elements of a connection device for the detachable connection of the adapter plate or the interchangeable unit to a support rail. If interchangeable units of this kind are provided, it is particularly easy and convenient for an end user to equip the honing tools with cutting surfaces optimally adapted to the machining task.

The tool system preferably comprises sets of adapter plates with different thicknesses and heights. This makes it possible to cover at least two different effective diameter ranges using one and the same support rail unit.

In order to facilitate the precisely fitting mounting of the cutting surfaces on the components of the honing tool that hold them, in many embodiments the support rails have at least two through-holes which are spaced apart from one another and extend from the outer side to the inner side and the interchangeable unit has connecting elements in the form of pins that can be introduced without play into the respective through-holes, wherein the pins preferably have a threaded section to create a screw connection between the interchangeable unit and the support rail unit.

The honing stone is the element that has the cutting surface. The cutting surface in the case of honing tools substantially consists of irregularly shaped cutting grains of different shapes and sizes which are bonded within a bonding system. By selecting the type of cutting surface, a honing tool can be precisely adapted to the desired machining task. The cutting grains may, for example, be diamond grains or grains made of cubic boron nitride (CBN). Cutting grains may also be made of corundum and/or other kinds of ceramic materials, such as SiC. The bonding may be made of a ceramic material or artificial resin. Metallic bonding systems, e.g. electroplated bonds or sintered bonds, are also possible, where necessary also soldered bonds.

It is possible for the honing stone to consist exclusively of the cutting surface. This may, for example, be a rail-shaped honing stone with a ceramic bond. In some embodiments, the honing stone has a multi-part design and includes a rail-shaped base plate that carries the cutting surface on one side. The base plate may be made of steel or another metallic material, for example. The cutting surface may be attached to the base plate by sintering, brazing, gluing, or by another adhesion method. The base plate can provide the honing stone or the cutting surface with additional mechanical stability.

The tool system offers a plurality of possible applications, while at the same time requiring a relatively small number of different tool components to be manufactured. In principle, it is possible to construct an entire tool system using a single type of tool body, as an end user can conveniently assemble honing tools for multiple different effective diameter ranges simply by using different sets of bolt guide elements in combination with correspondingly adapted sets of support rail units, covering a relatively large total effective diameter range overall.

It is also possible for a tool system to have only precisely two different tool bodies which, when used in conjunction with the tool components that can be attached thereto, allow an even greater variety of different effective diameter ranges. In a preferred variant, the tool system comprises exactly three different types of tool bodies, each with different dimensions and configurations. These tool bodies, in conjunction with the tool components that can be attached thereto, can cover almost all conceivable machining tasks across a very large total effective diameter range. An exemplary embodiment of a modular tool system is, for example, designed to cover a total effective diameter range from approximately 110 mm to 600 mm and in this case requires exactly three differently designed tool bodies.

When column-like bolt guide elements are used to expand the available effective diameter range when using a given tool body type, it may be desirable to further stabilize the overall arrangement against deformation due to high process forces during honing operations. In traditional tool systems of the kind referred to above, cage-like sheet metal constructions are provided for this purpose to act as a reinforcing frame. According to one development, the tool components comprise at least one set of ring-shaped stabilization elements, the number of which corresponds to the number of transverse bores in a bore group and which comprise receiving bores distributed around the circumference for receiving a column-like bolt guide element in each case. This ensures that the bolt guide elements attached to the tool body are not only stabilized by their secure attachment to the tool body, but also additionally supported at a greater distance from the tool axis near their free outer ends by means of the stabilization rings, increasing stability at a greater distance from the tool axis. Due to the ring-shaped design of the stabilization elements, which may also contain material cutouts to reduce weight, additional mechanical stabilization of the honing tool against deformation tendencies caused by machining forces can be achieved with minimal added weight.

The tool system can also optionally comprise components of a coolant and lubricant supply system that can be mounted on the tool body, in particular a connection and distribution ring that can be mounted on the tool body, in which a circumferential distribution channel is formed, as well as multiple nozzle pipes that communicate with the distribution channel, can be mounted axially parallel to the tool axis and at a radial distance from the tool body, with nozzle openings for dispensing coolant and lubricant.

The invention also relates to a method for manufacturing a honing tool that can be produced or configured using tool components of the tool system. In this case, a tool body of appropriate dimensions of the kind described here for the first time is selected, and a feed element is inserted into the receiving bore. Furthermore, a set of support rail units is selected, with a number of support rail units corresponding to the number of bore groups. Each support rail unit has a support rail with at least two guide pins on its inner side facing the tool body that can be introduced into transverse bores of a bore group and is designed to hold at least one honing stone. At least one honing stone is fastened to each of the support rail units. Before or even after in time, the support rail units are mounted on the tool body, wherein for this purpose the guide pins of the support rail units are introduced into the transverse bores provided therefor. Tool components of the tool system according to the claimed invention are used to manufacture the honing tool. If necessary, suitable bolt guide elements are preferably also included which are present in the tool system in the form of guide holders or guide columns, for example, and allow an increase in the effective diameter range that can be reliably achieved with a particular kind of tool body.

Below are presented exemplary embodiments of a modular tool system that includes a plurality of mutually coordinated tool components with the help of which honing tools can be configured for different applications. The example provided is a tool system with which honing tools can be assembled that can cover a total effective diameter range from 110 mm to 600 mm. Other total effective diameter ranges can of course also be covered based on the same principles.