Tools for machining workpieces
The tool design addresses the challenge of securely clamping cutting inserts by using a recess and support surface configuration to stabilize the insert, ensuring stable attachment and preventing motion, enabling efficient machining with indexable inserts.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HARTMETALL WERKZEUGFAB PAUL HORN
- Filing Date
- 2024-03-21
- Publication Date
- 2026-04-14
AI Technical Summary
Existing profile turning tools face challenges in securely clamping cutting inserts to the tool holder, leading to undesirable relative motion and instability, especially when using indexable inserts with multiple cutting edges, which are not adequately addressed in current technologies.
A tool design with a cutting insert receiving portion featuring a recess and mounting holes, where the cutting insert is arranged horizontally with multiple identical cutting edges, and a support surface configuration that disperses cutting forces, ensuring stable attachment and preventing relative motion between the insert and holder.
The design provides a stable and reproducible insert seat, preventing tilting and relative motion, allowing for efficient use of indexable inserts with multiple cutting edges, even in confined spaces, and enabling machining of complex profiles in a single operation.
Smart Images
Figure 2026511700000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a tool for machining a workpiece, the tool comprising a tool holder and a cutting insert, the cutting insert being attachable to the tool holder by an attachment element.
Background Art
[0002] The tool according to the present invention is configured particularly as a turning tool, and particularly preferably as a tool for profile turning.
[0003] General tools for profile turning are already known in principle in a number of forms. An exemplary cutting insert for such a profile turning tool is commercially available from the applicant under the name "profiling insert S117".
[0004] Profile turning is a well-known turning process of reference number 3.2.1.5, standardized in accordance with DIN (German Industrial Standard) 8589, and is used to create a rotationally symmetric shape on a workpiece. In profile turning, the shape to be created on the workpiece is formed negatively on the tool or the cutting insert of the tool. Thus, the cutting insert of such a tool is usually custom-made, and the shape to be generated on the workpiece area is formed negatively as the cutting profile of the cutting insert. The exception is standardized profile turning tools for creating grooves, undercuts, or round profiles.
[0005] A general advantage of such profile turning tools is that the profile to be reproduced on the workpiece can be created in a single operation. Otherwise, the machining of such profiles usually requires a plurality of different tools with differently shaped cutting edges, each of which only machines an individual segment of the profile to be created. Therefore, profile turning machining is highly productive and enables short machining times even for more complex shapes.
[0006] In profile turning, fundamental distinctions are made between longitudinal and transverse profile turning, internal and external profile turning, and groove machining and parting-off profile turning.
[0007] The cutting inserts in such profile turning tools are used in either a horizontal or vertical position, depending on the tool configuration.
[0008] The aforementioned cutting insert, marketed by the applicant under the name "Profiling Insert S117," is a cutting insert used in a horizontal position. This means it is positioned horizontally on a tool holder. Therefore, one of the two lateral sides of the cutting insert, which is relatively larger than the narrow side, is placed flat on the tool holder. Consequently, the extension of the cutting insert measured parallel to the cutting direction is smaller than the extension measured perpendicular to the depth of cut and / or feed direction.
[0009] However, in the vertical configuration of cutting inserts, the cutting insert is positioned upright on the tool holder, the cutting edge used is located on the narrower side of the cutting insert, and the extension of the cutting insert in the cutting direction is generally larger than the extension in the depth of cut and / or feed direction.
[0010] Because the shapes of "horizontal" cutting inserts and "vertical" cutting inserts are completely different, the way in which cutting inserts are attached to the tool holder and their intended uses are also completely different. For example, for cutting widths greater than 20 mm, only tools with "horizontal" cutting inserts are generally used because tools with "vertical" cutting inserts have very large cutting inserts, resulting in extremely high cemented carbide consumption. Even in machining operations where space requirements are relatively limited, such as turning inside holes, only "horizontal" inserts are generally used. Since the space required for internal diameter machining is limited by the hole radius, a relatively flat insert must be used. Therefore, in this application, the use of a "horizontal" cutting insert is far more advantageous than that of a "vertical" cutting insert.
[0011] To ensure reliable machining with clearly reproducible results, a stable and clearly reproducible method for clamping the cutting insert to the tool holder is also extremely important. Therefore, to ensure a stable insert seat, it is particularly important to configure the interface between the cutting insert and the tool holder to suit the specific application.
[0012] In the various tool systems for profile turning known to date, the fundamental problem of securely clamping the cutting insert to the tool holder has not been adequately solved. For example, the loads generated during machining can lead to undesirable relative motion between the cutting insert and the tool holder. However, this must be absolutely eliminated to achieve the desired machining quality.
[0013] Furthermore, from an economic standpoint, it is desirable to configure such profile turning cutting inserts as indexable inserts with multiple identical cutting edges, allowing them to be used multiple times by clamping the same cutting insert to a tool holder in different directions. If one cutting edge wears out, such an indexable insert is removed from the tool holder and then reattached to the tool holder in a different position, allowing another cutting edge that is not yet worn to be used. [Overview of the project] [Problems that the invention aims to solve]
[0014] Therefore, an object of the present invention is to provide a tool for machining a workpiece that eliminates or at least significantly overcomes the aforementioned drawbacks. In particular, an object of the present invention is to provide a tool for machining a workpiece, wherein the interface used to clamp the cutting insert to the tool holder is structurally improved to allow for a stable insert seat, and the cutting insert is configured as an indexable insert with multiple cutting edges that can be used sequentially. [Means for solving the problem]
[0015] This objective is achieved according to the present invention by the tool described in claim 1, wherein the tool holder has a cutting insert receiving portion for receiving a cutting insert, the cutting insert receiving portion comprising a recess formed in the support surface on the holder side. The base of the recess is penetrated by a mounting hole on the holder side, the hole axis of the mounting hole on the holder side extends laterally with respect to the longitudinal axis of the holder, and the mounting hole on the holder side helps to receive the mounting element. The recess is partitioned by two bearing surfaces on the holder side that are positioned laterally with respect to the base and laterally with respect to each other. The cutting insert has multiple identical cutting edges, which are arranged on a common cutting surface, formed in the transition between the upper and peripheral sides of the cutting insert, positioned at an angle offset from one another, and extending laterally from one another. The cutting insert has an insert-side support surface on the underside, opposite to the upper side, which is positioned parallel to the cutting surface. The cutting insert further has an extension that protrudes from the insert-side support surface and is inserted into the recess when the tool is mounted, and three insert-side bearing surfaces that extend laterally from each other are positioned laterally on the extension. The cutting insert extends further through the extension and has mounting holes on the insert side that penetrate the upper and lower sides, with the hole axes of the mounting holes positioned perpendicular to the cutting surface and functioning to receive the mounting element. The support surface on the insert side contacts the support surface on the holder side when the tool is mounted. Of the three support surfaces on the insert side, the first support surface contacts the first support surface of the two bearing surfaces on the holder side when the tool is mounted, and the second support surface of the three support surfaces on the insert side contacts the second support surface of the two bearing surfaces on the holder side when the tool is mounted.
[0016] Thus, the tool according to the present invention has a cutting insert arranged horizontally on a tool holder. This cutting insert is configured as an indexable insert and has a plurality of identical cutting edges arranged at an angle offset from each other in the transition portion between the upper and peripheral sides of the cutting insert.
[0017] In other words, the cutting insert of the tool according to the present invention has at least two identical cutting edges. Preferably, the tool according to the present invention has at least three identical cutting edges. Particularly preferably, the tool according to the present invention has exactly three identical cutting edges. However, depending on the configuration, the cutting insert of the tool according to the present invention may also include four, five, six, or more identical cutting edges, all of which are on a common cutting surface.
[0018] The cutting insert of the tool according to the present invention is preferably configured to be rotationally symmetric with respect to the hole axis of the mounting hole on the insert side. Therefore, it is preferable that the cutting edges of the cutting insert are offset from each other by a certain angle. In other words, one of these cutting edges can be aligned with another of these cutting edges by rotating it by a certain angle around the hole axis of the mounting hole on the insert side. The specific rotation angle depends on the number of cutting edges and is the result of the quotient obtained by dividing 360° by the number of identical cutting edges.
[0019] In a preferred embodiment of a cutting insert having exactly three identical cutting edges, these cutting edges are thus aligned with each other by rotating 120° around the axis of the mounting hole on the insert side. According to this preferred embodiment, the cutting insert is preferably rotationally symmetric by 120° as a whole about the axis of the mounting hole on the insert side.
[0020] The number of bearing surfaces on the insert side preferably corresponds to the number of cutting edges provided on the cutting insert. Also, the bearing surfaces on the insert side are preferably arranged such that they are offset from each other by a certain angle (for example, 120°) around the axis of the mounting hole on the insert side.
[0021] Furthermore, it should be noted that the term "lateral" does not necessarily mean perpendicular, but rather any spatial alignment of two structures (for example, surfaces or cutting edges) that form an angle greater than 0° between them, that is, not parallel to each other.
[0022] For example, in a tool according to the present invention, the axis of the mounting hole on the holder side preferably extends laterally with respect to the longitudinal axis of the holder, that is, not parallel but perpendicular to the longitudinal axis of the holder. The two bearing surfaces on the holder side preferably extend laterally, that is, not parallel but perpendicular to the base of the recess. The two bearing surfaces on the holder side preferably extend laterally, that is, not parallel but are arranged at an acute angle to each other. The cutting edges arranged on the cutting insert preferably extend laterally with respect to each other, that is, not parallel but form an acute angle between those cutting edges. The same applies to (at least) three bearing surfaces on the insert side.
[0023] An interface provided on the tool holder in accordance with the present invention between the cutting insert and the cutting insert receiving portion provides various technical advantages.
[0024] The horizontal arrangement of the cutting insert is achieved by placing the cutting insert flat against the support surface on the holder side, arranging the support surface on the insert side downward, and aligning it parallel to the cutting surface. As a result, a very flat and space-saving configuration can be achieved. Thereby, the tool according to the present invention can be used even in limited machining situations, such as when machining an internal hole.
[0025] The two support surfaces (the support surfaces on the insert side and the holder side) are usually arranged perpendicular to the cutting direction during turning. Therefore, most of the cutting force is introduced into the tool holder at the contact point between these two support surfaces.
[0026] Due to their geometric shape, these two support surfaces can be configured to be relatively large, so that the introduction of force can be dispersed over a relatively large area, thereby reducing the contact pressure between the cutting insert and the tool holder caused by the cutting force.
[0027] The machining forces (e.g., feed force and passive force) acting laterally on it during turning are substantially absorbed in the tool according to the present invention by the bearing surface on the holder side and the corresponding bearing surface on the insert side.
[0028] In this regard, it is advantageous that the bearing surface and the support surface are arranged on different parts of the cutting insert or on different parts of the cutting insert receiving part, and these parts are structurally and spatially separated from each other.
[0029] The bearing surface on the holder side is formed by the side wall of the recess formed on the support surface on the holder side. The bearing surface on the insert side is arranged horizontally on an extension protruding from the support surface on the insert side. This separation of the bearing surface and the support surface has a positive effect on the mechanical stability of the insert seat. In particular, this can effectively prevent relative movement related to the load between the cutting insert and the tool holder generated during machining.
[0030] Furthermore, the structural and spatial separation of the support surface and the bearing surface makes it possible to make the recesses in the cutting insert receiving section and the corresponding extensions on the cutting insert relatively small, thereby saving space in the overall arrangement. If support surfaces intended to absorb cutting forces are also provided in the recesses or extensions, the recesses and extensions must be significantly larger or more rigid.
[0031] Therefore, the above-mentioned objective is fully achieved.
[0032] According to a preferred embodiment, the support surface on the insert side completely surrounds the extension. This means that the support surface on the insert side surrounds the extension along its entire circumference, rather than surrounding only a portion of it.
[0033] This has a very positive effect on the mechanical stability of the insert seat. On the one hand, it allows for a larger support surface on the insert side. On the other hand, since the cutting insert is supported around the entire circumference of the extension, it effectively prevents tilting of the cutting insert due to load.
[0034] In a further embodiment, the support surface on the holder side completely encloses the recess. This means that the support surface on the holder side encloses the recess not only in part, but around its entire perimeter.
[0035] This also has a positive effect on the mechanical stability of the insert seat, as the tool holder can support the underside of the cutting insert along the entire circumference of the recess. Furthermore, since the recess is fully formed in the solid part of the tool holder, it prevents part of the recess from cracking.
[0036] The support surface on the holder side and the support surface on the insert side are preferably configured as flat surfaces. Similarly, the bearing surface on the holder side and the bearing surface on the insert side are preferably configured as flat surfaces. This allows for clear and flat support or contact of the cutting insert on the tool holder.
[0037] In a further embodiment, the cross-section of the extension perpendicular to the hole axis of the mounting hole on the insert side substantially has the shape of a regular polygon with rounded corners. In the case of a 120° rotationally symmetric cutting insert, it is preferable that the cross-section of the extension substantially corresponds to the shape of an equilateral triangle with rounded corners.
[0038] This embodiment has the advantage that the bearing surface on the insert side, positioned on the extension, is provided as a regular surface corresponding to the cutting edge of the cutting insert.
[0039] In an embodiment of a cutting insert having exactly three cutting edges, it is therefore preferable, according to one embodiment, that the bearing surfaces on the insert side form a 60° angle between them, as in the case of an equilateral triangle. Preferably, according to this embodiment, the bearing surfaces on the holder side also form a 60° angle between them.
[0040] In a further embodiment, the hole axis of the insert-side mounting hole is positioned perpendicular to the longitudinal axis of the holder.
[0041] According to the present invention, since the hole axis is arranged perpendicular to the cutting surface, the cutting surface according to this embodiment extends parallel to the longitudinal axis of the holder.
[0042] In a further embodiment, the height of the extension, measured parallel to the hole axis of the mounting hole on the insert side, is smaller than the depth of the recess, measured parallel to the hole axis of the mounting hole on the holder side.
[0043] Therefore, the cutting insert remains stationary perpendicular to the hole axis only when the support surface on the insert side is in contact with the support surface on the holder side. However, the extension protruding from the support surface on the insert side does not contact the base of the recess. This ensures a clearly defined mechanical support structure for the cutting insert.
[0044] In a further embodiment, the extension has a flat end face which extends laterally with respect to the bearing surface on the insert side, is passed through a mounting hole, and is positioned perpendicular to the hole axis of the mounting hole on the insert side.
[0045] The mounting hole on the insert side preferably extends to the center through the extension and therefore also extends to the center through the flat end face.
[0046] In a further embodiment, the two holder-side bearing surfaces are each at a first distance from the hole axis of the holder-side mounting hole, and the recess is further laterally demarcated by a side surface extending laterally with respect to the base and laterally with respect to the two holder-side bearing surfaces, the side surface being at a second distance greater than the first distance from the hole axis of the holder-side mounting hole.
[0047] The aforementioned side surface also forms the side wall of the recess. However, unlike the two holder-side bearing surfaces that form the other side walls of the recess, the aforementioned side surface is located further away from the hole axis of the mounting hole on the holder side. The cross-section of the recess perpendicular to the hole axis of the mounting hole on the holder side is a substantially isosceles triangle with rounded corners.
[0048] This ensures that, in the tool-mounted state, only two of the three insert-side bearing surfaces contact the tool holder or the holder-side bearing surface. However, the third insert-side bearing surface is spaced apart from the aforementioned side surface of the recess in the tool-mounted state.
[0049] It is understood that this third insert-side bearing surface, which does not come into contact with the tool holder, may be a different surface among the three insert-side bearing surfaces, depending on how the cutting insert is mounted to the tool holder (i.e., which of the multiple cutting edges is used). Therefore, although all three surfaces are referred to as the insert-side bearing surfaces here, in this embodiment, only two of the three insert-side bearing surfaces contact the tool holder when installed.
[0050] According to the latter embodiment, the recess is configured to be somewhat larger than the extension that is positioned on the cutting insert and functions as its corresponding portion. More precisely, the cross-section of the recess positioned perpendicular to the hole axis of the mounting hole on the holder side is larger than the cross-section of the extension positioned perpendicular to the hole axis of the mounting hole on the insert side.
[0051] This facilitates the insertion of the extension into the recess. Furthermore, it creates precisely defined surface contact between the two bearing surfaces on the insert side that engage.
[0052] In a further embodiment, when the tool is mounted, the first cutting edge of the plurality of cutting edges is positioned in the region of the cutting insert that protrudes laterally from the tool holder, and the first cutting edge is at a shorter distance from the side than from the bearing surfaces on the two holder sides.
[0053] This so-called "first cutting edge" is the cutting edge of the cutting insert currently used in machining. Thus, the cutting insert contacts the tool holder along with two bearing surfaces on the insert side that are furthest from the cutting edge used for machining. This also further improves the mechanical stability of the insert seat. The cutting insert is effectively retracted into the tool holder, away from the active cutting edge.
[0054] In a further embodiment, the height of the extension, measured parallel to the hole axis of the mounting hole on the insert side, is less than 40% of the total height of the cutting insert, measured parallel to the hole axis. Particularly preferably, this height of the extension is less than 35% of the total height of the cutting insert. In particular, it is preferable that the height of the extension is 25% to 35% of the total height of the cutting insert.
[0055] Therefore, the extension has a relatively low height. Consequently, even though the extension is positioned on the cutting insert, a relatively flat cutting insert can be achieved. This makes the cutting insert suitable for machining in confined spaces.
[0056] In a further embodiment, the cutting insert receiving portion is positioned within a notch provided in the tool holder, the notch having a side wall that partially surrounds the support surface on the holder side, the side wall being positioned laterally with respect to the support surface on the holder side, and in the tool-mounted state, surrounding two of the multiple cutting edges of the cutting insert.
[0057] This notch is larger than the recess in the holder-side support surface, as it at least partially surrounds the support surface on the holder side. The sidewalls of this notch are particularly useful in protecting the two inactive cutting edges of the cutting insert so that they are not damaged before they can be used as active cutting edges for machining.
[0058] It is understood that the features described above and those described below may be used not only in the specific combinations in each case, but also in other combinations or by themselves without departing from the scope of the present invention. [Brief explanation of the drawing]
[0059] Exemplary embodiments of the present invention are shown in the drawings and described in more detail below. [Figure 1] This is a perspective view of an exemplary embodiment of a tool according to the present invention. [Figure 2]Figure 1 is a top view of the tool shown, illustrating a workpiece machined by the tool according to the present invention and shown in cross-section. [Figure 3] Figure 1 is an exploded view of the tool shown. [Figure 4a] This is a diagram of various cutting inserts that can be used in the tool of Figure 1 according to a first exemplary embodiment. [Figure 4b] This is a diagram of various cutting inserts that can be used in the tool of Figure 1 according to a first exemplary embodiment. [Figure 4c] This is a diagram of various cutting inserts that can be used in the tool of Figure 1 according to a first exemplary embodiment. [Figure 4d] This is a diagram of various cutting inserts that can be used in the tool of Figure 1 according to a first exemplary embodiment. [Figure 5a] This figure shows various cutting inserts that can be used in the tool of Figure 1, according to a second exemplary embodiment. [Figure 5b] This figure shows various cutting inserts that can be used in the tool of Figure 1, according to a second exemplary embodiment. [Figure 5c] This figure shows various cutting inserts that can be used in the tool of Figure 1, according to a second exemplary embodiment. [Figure 5d] This figure shows various cutting inserts that can be used in the tool of Figure 1, according to a second exemplary embodiment. [Figure 6a] Figure 1 is a perspective view of the tool holder of the tool shown. [Figure 6b] Figure 1 is a top view of the tool holder of the tool shown. [Figure 7] Figure 1 is a partial longitudinal cross-sectional view of the tool shown. [Figure 8] Figures 6a and 6b are partial longitudinal cross-sectional views of the tool holder. [Figure 9] Figures 4a to 4d are longitudinal cross-sectional views of the cutting inserts. [Modes for carrying out the invention]
[0060] Figure 1 is a perspective view showing an exemplary embodiment of a tool according to the present invention. The tool is indicated as a whole by reference numeral 10.
[0061] The tool 10 comprises a tool holder 12 and a cutting insert 14 that is removably mounted on the tool holder 12. The cutting insert 14 is mounted in a cutting insert receiving portion 16, which is located in the front end region of the tool holder 12 and is inserted into one side of the tool holder 12 by a mounting screw 18 (see Figure 3).
[0062] In the mounted state of the tool 10, the mounting screw 18 extends through the mounting hole 20, which is centrally located within the cutting insert 14 and is referred to here as the insert-side mounting hole 20. It is inserted into a mounting hole 22 provided within the tool holder 12, which has threads 24 corresponding to the mounting screw 18 and is referred to here as the holder-side mounting hole 22. The screw is then screwed into the threads 24 (see Figure 7).
[0063] In particular, as can be seen in Figure 2, the mounting screw 18 is positioned eccentrically within the mounting hole 20 on the insert side when the tool 10 is mounted. In other words, the longitudinal axis 26 of the mounting screw 18 is slightly off-center from the hole axis 28 of the mounting hole 20 on the insert side. However, the longitudinal axis of the mounting screw 18 coincides with the hole axis 30 of the mounting hole 22 on the holder side. Therefore, the hole axis 28 of the mounting hole 20 on the insert side is also offset laterally by a fraction of a millimeter (for example, 0.1 mm to 0.2 mm) parallel to the hole axis 30 of the mounting hole 22 on the holder side when the tool 10 is mounted. As a result, the cutting insert 14 is subjected not only to an axial clamping force along the longitudinal axis 26 of the mounting screw 18, but also to a lateral clamping force, and this clamping force pulls the cutting insert 14 into the cutting insert receiving portion 16.
[0064] In the exemplary embodiment shown herein, a plurality of internal coolant channels are arranged within the tool holder 12, which open into a plurality of coolant outlets 32 aligned with the cutting insert 14, supplying coolant / lubricant during machining. The coolant channels preferably extend inward through a clamp portion 34 located on the rear side of the tool holder 12, although this is not explicitly shown herein. This clamp portion 34 serves to secure the tool 10. Generally, the elongated clamp portion 34 extends along the longitudinal axis 36 of the tool holder 12.
[0065] The cutting insert receiving portion 16 is located on the front side of the tool holder 12 opposite to the clamp portion 34 and has a flat surface 38, which is positioned parallel to the holder's longitudinal axis 36 and is referred to herein as the holder-side support surface 38. A recess 40 is formed in this holder-side support surface 38. The bottom of this recess 40 is separated by a base 42, which is positioned parallel to the holder-side support surface 38 and offset from the holder-side support surface 38. The holder-side mounting hole 22 extends vertically through this base 42 of the recess 40.
[0066] The recess 40 is laterally divided by three flat surfaces 44, 46, and 48. These three flat surfaces 44, 46, and 48 form the side walls of the recess 40 and are each aligned laterally, preferably perpendicular to, the base 42 of the recess 40.
[0067] In particular, as can be seen in Figure 6b, the cross-section of the recess 40, which is aligned perpendicular to the hole axis 30 of the mounting hole 22 on the holder side, has the shape of an isosceles triangle with rounded corners, and the three flat surfaces 44, 46, and 48 form the three sides of the isosceles triangle in this cross-section.
[0068] As will be explained in detail below, only two of these three flat bearing surfaces 44, 46, and 48 act as lateral bearing surfaces that contact the cutting insert 14 when it is mounted on the tool 10. More precisely, these bearing surfaces are the flat surfaces 44 and 46. Therefore, in this example, the flat surface 44 will be referred to as the bearing surface 44 on the first holder side, the flat surface 46 as the bearing surface 46 on the second holder side, and the flat surface 48 as the side surface 48 of the recess 40.
[0069] A first exemplary embodiment of the cutting insert 14 of the tool 10 according to the present invention is shown in various figures in Figures 4a to 4d and Figure 9. Figure 4a is a perspective view of the upper side of the cutting insert 14. Figure 4b is a perspective view of the lower side of the cutting insert 14. Figure 4c is a side view of the cutting insert 14. Figure 4d is a plan view of the lower side of the cutting insert 14. Figure 9 is a cross-sectional view of the cutting insert 14, the cross-section of which extends along the hole axis 28 of the mounting hole 20 on the insert side.
[0070] The cutting insert 14 is configured as an indexable insert. The cutting insert 14 is 120° rotationally symmetric with respect to the hole axis 28 of the mounting hole 20 on the insert side, and has three identically formed cutting edges 50, 52, and 54. All three cutting edges 50, 52, and 54 are formed in the transition area between the side 56 and the peripheral side 58. The three cutting edges 50, 52, and 54 are located within a common cutting surface E. The cutting surface E is shown by a dashed line in Figure 9.
[0071] These three cutting edges 50, 52, and 54 each correspond to the negative shape of the profile to be generated on the workpiece by the tool 10 according to the present invention. Such a profile 60 is schematically shown in Figure 2. The profile 60 shown in Figure 2 is generated on the workpiece 62 by the tool 10 according to the present invention, and here corresponds to the internal profile introduced into the hole in the workpiece 62.
[0072] A special feature of generating this profile 60 by the tool 10 according to the present invention is that this profile 60 is introduced into the workpiece 62 in a single operation with the same tool 10. To ensure this, the cutting edge contours of each of the three cutting edges 50, 52, and 54 are precisely matched to the shape of the resulting profile 60. Thus, each of the three cutting edges 50, 52, and 54 has multiple cutting edges aligned orthogonally to each other.
[0073] In this embodiment, the cutting edges 50, 52, and 54 are each configured as straight cutting edges. However, it is understood that one or more of these cutting edges may be configured as curved cutting edges depending on the profile being manufactured. It is also understood that the cutting insert 14 can be used not only for turning internal profiles but also for turning external profiles.
[0074] On the lower side 64 opposite the upper side 56, the cutting insert 14 has a flat support surface 66, which in this case is referred to as the insert-side support surface 66. This insert-side support surface 66 extends perpendicular to the hole axis 28 of the mounting hole 20 on the insert side and parallel to the cutting surface E.
[0075] Furthermore, the cutting insert 14 has an extension 68 on its lower side 64, which protrudes from the support surface 66 on the insert side. This extension 68 acts in accordance with the recess 40 formed in the cutting insert receiving portion 16. The mounting hole 20 on the insert side extends to the center through this extension 68. The end face 70 of the extension 68 is configured as a flat support surface, which is passed through by the mounting hole 20 on the insert side and is positioned perpendicular to the hole axis 28 of the mounting hole 20 on the insert side.
[0076] Furthermore, three surfaces 72, 74, and 76 are arranged laterally on the extension 68 and aligned laterally with one another, and these surfaces are referred to here as the first insert-side bearing surface 72, the second insert-side bearing surface 74, and the third insert-side bearing surface 76. In this exemplary embodiment, these three insert-side bearing surfaces 72, 74, and 76 are arranged at an angle of 60° to each other. They extend perpendicular to the insert-side support surface 66 and parallel to the hole axis 28 of the insert-side mounting hole 20. All three insert-side bearing surfaces 72, 74, and 76 are at the same distance from the hole axis 28 of the insert-side mounting hole 20.
[0077] While the recess 40 has the shape of an isosceles triangle with rounded edges in cross-section, the extension 68 positioned on the cutting insert 14 has the shape of an equilateral triangle with rounded corners in cross-section, positioned perpendicular to the hole axis 28.
[0078] The height of the extension 68 is relatively small compared to the overall height of the cutting insert 14. Preferably, the height h of the extension, measured parallel to the hole axis 28, is less than 40% of the height h of the cutting insert 14, measured parallel to the hole axis 28, and particularly preferably less than 30% (see Figure 4c).
[0079] Furthermore, the height h of the extension 68 positioned on the cutting insert 14 is smaller than the depth t of the recess 40, which is measured parallel to the hole axis 30 of the mounting hole 22 on the holder side (see Figure 8). As a result, the end face 70 of the extension 68 does not contact the base 42 of the recess 40 when the tool 10 is mounted (see Figure 7).
[0080] Instead, in the mounted state of the tool 10, the cutting insert 14 is placed such that its insert-side support surface 66 is in flat contact with the holder-side support surface 38 according to the first exemplary embodiment of the cutting insert 14 (see Figure 7). In addition, according to the first exemplary embodiment, when the tool 10 is mounted, two of the three insert-side bearing surfaces 72, 74, and 76 of the cutting insert 14 are placed against the holder-side bearing surfaces 44, 46.
[0081] Since the cross-sectional area of the recess 40 is larger than the cross-sectional area of the extension 68, when the tool 10 is mounted, the third of the three insert-side bearing surfaces 72, 74, and 76 located on the opposite side of the side 48 of the recess 40 is away from the side 48 and therefore does not contact the side 48. This is due in particular to the fact that the bearing surfaces 44 and 46 on the two holder sides are at a first distance from the hole axis 30 of the mounting hole 22 on the holder side, while the side surface 48 is at a second distance greater than the first distance from the hole axis 30.
[0082] In particular, as seen in Figures 4d and 6b, the insert-side support surface 66 of the cutting insert 14 in the first exemplary embodiment surrounds the entire circumference of the extension 68. Similarly, the support surface 38 on the holder side surrounds the entire circumference of the recess 40. This enables extremely stable support of the cutting insert 14, which in particular prevents tilting of the cutting insert 14 depending on the load.
[0083] Figures 5a to 5d show a second exemplary embodiment of the cutting insert 14 in four different figures corresponding to the figures in Figures 4a to 4d. In contrast to the first exemplary embodiment shown in Figures 4a to 4d, the cutting insert 14 according to the second exemplary embodiment shown in Figures 5a to 5d is configured as a sintered cutting insert, and this cutting insert has several configuration differences due to the manufacturing process.
[0084] First, multiple ridges are provided on the lower side 64 of the cutting insert, and a portion of the support surface 66 on the insert side is formed on its end face. As a result, the support surface 66 on the insert side is divided into three segments 66.1, 66.2, and 66.3, which are distributed along the lower side 64 of the cutting insert 14. Each of these three segments has a plane, and these planes are located within a common support plane, together forming the support plane 66 on the insert side. In other words, the cutting insert 14 here has three support surfaces 66.1, 66.2, and 66.3. In contrast to the cutting insert 14 shown in Figures 4a to 4d, the cutting insert 14 shown in Figures 5a to 5d, when mounted on the tool 10, does not have its entire surface, indicated here by reference numeral 67, in contact with the support surface 38 on the holder side, but rather only has three support surfaces 66.1, 66.2, and 66.3 in contact.
[0085] Furthermore, recesses 75 are formed in each of the bearing surfaces 72, 74, and 76 on the insert side, which are arranged laterally on the extension portion 68. Accordingly, the insert-side bearing surfaces 72, 74, and 76 are also divided into two segments, 72.1, 72.2, 74.1, 74.2, and 76.1, 76.2, respectively. The two segments 72.1, 72.2 or 74.1, 74.2 or 76.1, 76.2 of each bearing surface 72, 74, and 76 are spaced apart from each other, lie within one plane, and in each case are separated by one of the recesses. In other words, it can also be said that the cutting insert has two first insert-side bearing surfaces 72.1, 72.2, two second insert-side bearing surfaces 74.1, 74.2, and two third insert-side bearing surfaces 76.1, 76.2.
[0086] In the mounted state of the tool 10, the cutting insert 14 causes both segments 72.1, 72.2 or 74.1, 74.2 or 76.1, 76.2 of the bearing surfaces 72, 74, and 76 on the insert side to abut against the bearing surface 44 or 48 on the holder side. For example, two segments 72.1 and 72.2 abut against the first holder-side bearing surface 44, and two segments 74.1 and 74.2 abut against the second holder-side bearing surface 48.
[0087] The three insert-side support surfaces 66.1, 66.2, and 66.3 are located on different sides of the extension 68. In other words, each of these three support surfaces 66.1, 66.2, and 66.3 is geometrically assigned to one of the three insert-side bearing surfaces 72, 74, and 76. Thus, the cutting insert 14 according to the second exemplary embodiment shown in Figures 5a to 5d has a kind of three-point support, ensuring a stable insert seat, similar to the cutting insert 14 according to the first embodiment.
[0088] Regardless of the type of configuration of the cutting insert 14, the cutting insert receiving portion 16 is arranged as a notch 78, which is provided on the tool holder 12 and is laterally separated by a side wall 80, which partially surrounds the support surface 38 on the holder side and is positioned laterally with respect to the support surface 38. The notch 78 or its side wall 80 has the specific purpose of protecting two inactive cutting edges 52, 54 from damage.
Claims
1. A tool (10) for machining a workpiece, comprising a tool holder (12) extending along the longitudinal axis (36) of the holder, and a cutting insert (12) attached to the tool holder (12) by a mounting element (18), The tool holder (12) has a cutting insert receiving portion (16) for receiving a cutting insert (14), and the cutting insert receiving portion (16) has a recess (40) formed on the support surface (38) on the holder side. The base (42) of the recess (40) is penetrated by the mounting hole (22) on the holder side, the hole axis (30) of the mounting hole (22) on the holder side extends laterally with respect to the longitudinal axis (36) of the holder, the mounting hole (22) on the holder side helps to receive the mounting element (18), the recess (40) is separated by two bearing surfaces (44, 46) on the holder side that are positioned laterally with respect to the base (42) and positioned laterally with respect to each other, The cutting insert (14) has a plurality of identical cutting edges (50, 52, 54), which are arranged on a common cutting surface (E), formed in the transition area between the upper side (56) and the peripheral side (58) of the cutting insert (14), arranged at an angle offset from each other, and extending laterally from each other. The cutting insert (14) has, on its lower side (64) opposite to its upper side (56), an insert-side support surface (66) positioned parallel to the cutting surface (E), and an extension (68) that protrudes from the insert-side support surface (66) and is inserted into the recess (40) when the tool (10) is mounted. Three insert-side bearing surfaces (72, 74, 76) extending laterally from one another are arranged laterally on the extension (68), and the cutting insert (14) further extends through the extension (68) and has an insert-side mounting hole (20) that penetrates the upper (56) and lower (64), the hole axis (28) of the mounting hole (20) is positioned perpendicular to the cutting surface (E) and functions to receive the mounting element (18), The support surface (66) on the insert side contacts the support surface (38) on the holder side when the tool (10) is mounted. The tool (10) is characterized in that, in the mounted state of the tool (10), the first support surface of the three insert-side support surfaces (72, 74, 76) abuts against the first support surface of the two holder-side bearing surfaces (44, 46), and the second support surface of the three insert-side support surfaces (72, 74, 76) abuts against the second support surface of the two holder-side bearing surfaces (44, 46).
2. The tool according to claim 1, wherein the support surface (66) on the insert side completely surrounds the extension (68).
3. The tool according to claim 1 or 2, wherein the support surface (38) on the holder side completely surrounds the recess (40).
4. The tool according to any one of claims 1 to 3, wherein the bearing surfaces (44, 46) on the holder side and the bearing surfaces (72, 74, 76) on the insert side are each configured as flat surfaces.
5. The tool according to any one of claims 1 to 4, wherein the cross-section of the extension portion (68), which is arranged perpendicular to the hole axis (28) of the mounting hole (20) on the insert side, substantially has the shape of a regular polygon with rounded corners.
6. The tool according to claim 4 or 5, wherein the bearing surfaces (72, 74, 76) on the insert side form a 60° angle between the bearing surfaces.
7. The tool according to any one of claims 1 to 6, wherein the bearing surfaces (72, 74, 76) on the insert side are arranged parallel to the hole axis (30) of the mounting hole (22) on the insert side.
8. The tool according to any one of claims 1 to 7, wherein the hole axis (28) of the mounting hole (20) on the insert side is arranged perpendicular to the longitudinal axis (36) of the holder.
9. The tool according to any one of claims 1 to 8, wherein the height (h) of the extension (68), measured parallel to the hole axis (28) of the mounting hole (20) on the insert side, is smaller than the depth (t) of the recess (40), measured parallel to the hole axis (30) of the mounting hole (22) on the holder side.
10. The tool according to any one of claims 1 to 9, wherein the extension (68) has a flat end face (70) that extends laterally with respect to the bearing surfaces (72, 74, 76) on the insert side, the end face (70) is passed through by the mounting hole (20) on the insert side, and is positioned perpendicular to the hole axis (28) of the mounting hole (20) on the insert side.
11. The tool according to any one of claims 1 to 10, wherein the cross-section of the recess (40) positioned perpendicular to the hole axis (30) of the mounting hole (22) on the holder side is larger than the cross-section of the extension (68) positioned perpendicular to the hole axis (28) of the mounting hole (20) on the insert side.
12. The tool according to claim 11, wherein the two holder-side bearing surfaces (44, 46) are each at a first distance from the hole axis (30) of the holder-side mounting hole (22), and the recess (40) is further divided laterally by a side surface (48) that is positioned laterally with respect to the base (42) and laterally with respect to the two holder-side bearing surfaces (44, 46), the side surface being at a second distance from the hole axis (30) of the holder-side mounting hole (22), and the second distance being greater than the first distance.
13. The tool according to claim 12, wherein, in the mounted state of the tool (10), the first cutting edge among the plurality of cutting edges (50, 52, 54) is positioned in the region of the cutting insert (14) that protrudes laterally from the tool holder (12), and the first cutting edge (50) is at a shorter distance from the side surface (48) than the two holder-side bearing surfaces (44, 46).
14. The tool according to any one of claims 1 to 13, wherein the height (h) of the extension (68), measured parallel to the hole axis (28) of the mounting hole (20) on the insert side, is less than 40% of the total height (H) of the cutting insert (14), measured parallel to the hole axis (28).
15. The cutting insert receiving portion (16) is positioned within a notch (78) provided in the tool holder (12), the notch having a side wall (80) that partially surrounds the support surface (38) on the holder side, the side wall being positioned laterally with respect to the support surface (38) on the holder side, and in the mounted state of the tool (10), surrounding two of the plurality of cutting edges (50, 52, 54) of the cutting insert (14), as described in any one of claims 1 to 14.