TOOL SYSTEM

Description

[0001] The present invention relates to a tool system comprising a tool carrier and an interchangeable cutting insert. State of the art

[0002] Even if their cutting edges are made of carbide or other hard materials, turning tools are subject to heavy wear and require frequent re-sharpening or replacement. Due to the high material and manufacturing costs, solid carbide turning tools usually have only one cutting edge and are designed for a limited range of applications. Once worn, they must be removed from the machine.

[0003] However, turning tools can also have multiple cutting edges. By rotating the turning tool, a fresh cutting edge can be used when one cutting edge becomes worn, without having to completely remove the turning tool from the machine. This avoids delays caused by replacing the turning tool and the resulting need for repositioning it in the machine.

[0004] DE 10 2004 013 835 A1 describes such a turning tool, designed for internal turning. Several cutting edges, which can be selectively engaged, radiate in a star shape from a tool head that is integrally connected to a tool shank.

[0005] However, using such a tool can lead to unplanned damage to the cutting edges not in use. A small chip lifted from the active cutting edge and grazing the passive cutting edges is often enough to damage them to the point where they no longer meet high machining quality standards. This would render the entire insert scrap.

[0006] WO 2007 / 006575 A1 describes a finishing tool with six tangentially arranged cutting edges on its face, all of which are of identical design. Support surfaces adjacent to each cutting edge rest against the wall of a bore to be machined.

[0007] A plunge knife is known from DE 295 08 900. This knife has a cutting edge that can be brought into cutting engagement and is arranged on a clamp holder. The cutting edge is attached to a seat of the clamp holder by means of a screw.

[0008] An object of the present invention is to provide a tool system which can be used in particular as a turning tool and on which a plurality of cutting edges are arranged in such a way that an active cutting edge can be used without there being a risk of damaging the passive cutting edges. Disclosure of the invention

[0009] This object is achieved according to the invention by a tool system which has a tool holder and an interchangeable cutting insert with preferably at least three cutting edges. It is particularly preferred that it has exactly three cutting edges. A cutting edge is understood not only to be the ground area of ​​a cutting part, but the entire cutting part which is defined by the rake face and flank face. The tool holder has a neck with a seat on which the interchangeable cutting insert is arranged. A neck is understood to be an area which is usually adapted to a diameter to be machined. The neck usually has a circular-cylindrical cross-section. Adjacent to the neck of the tool holder is a receiving area which is used to clamp the tool holder in a machine or in another receiving element.Preferred materials for the tool carrier are steel, a combination of hard metal and steel or a combination of heavy metal and steel.

[0010] The cutting edges of the interchangeable insert are essentially orthogonal to the longitudinal axis of the tool holder. This allows the tool system to be used as a turning tool. It is particularly suitable for machining diameters from 7.8 mm upwards.

[0011] The neck has a protective area that protrudes beyond the seat along its longitudinal axis and surrounds all cutting edges of the interchangeable cutting insert except one. In particular, it extends at least to a ground area of ​​these cutting edges. While the exposed cutting edge can be used for material processing, all non-working cutting edges are protected by the protective area from potential chips and associated damage. The protective area is preferably formed integrally with the neck.

[0012] In order to ensure particularly reliable protection of the non-working cutting edges from possible chips, it is preferred that a length of the protective area along the longitudinal axis is equal to a length of the interchangeable cutting insert.

[0013] In addition to protecting the non-working cutting edges, the protective area can also be used to securely fix the interchangeable cutting insert to the tool holder and ensure effective transmission of forces acting on the active cutting edge via the interchangeable cutting insert into the tool holder. For this purpose, it is preferable for the protective area to be in contact with the interchangeable cutting insert in sections. This contact is preferably made against a peripheral surface of the interchangeable cutting insert.

[0014] The protective area is preferably designed as a circular arc-shaped projection. As such, it can continue the neck along the longitudinal axis of the tool holder and tightly enclose the interchangeable cutting insert. For each cutting edge it surrounds, the protective area preferably has a recess in which the respective cutting edge is received. In this way, the protective area can have a continuously running surface on its outer side, i.e. the side facing a workpiece, while its inner side, i.e. the side facing the interchangeable cutting insert, has the recesses. As a result, the thickness of the protective area varies in the area of ​​the passive cutting edges. To ensure reliable protection of the passive cutting edges, it is further preferred that the circumferential length of the protective area, measured along its curved outer surface, corresponds to at least 33% of the circumference of the neck.If the neck has a circular cross-section, this means that the protected area extends over a circular arc with an angle of at least 120°. Particularly preferably, the circumferential length of the protected area corresponds to at least 50% of the circumference of the neck.

[0015] If the neck has a circular cross-section, this means that the protection area extends over an arc with an angle of at least 180°.

[0016] One side surface of each recess is preferably angled relative to the longitudinal axis. This enables the passive cutting edges to be accommodated when the interchangeable cutting insert is angled relative to the longitudinal axis of the tool holder. Such an angle is preferred. This means that the interchangeable cutting insert is clamped to the seat not along the longitudinal axis of the tool holder, but at an angle to it. This results in advantageous force absorption by the tool system when machining a workpiece. An angle of the interchangeable cutting insert relative to the longitudinal axis of a maximum of 10° is preferred and a maximum of 5° is particularly preferred. Furthermore, the angle is preferably at least 1° and particularly preferably at least 2°. The seat is angled relative to the longitudinal axis by the same angle as the interchangeable cutting insert.

[0017] Furthermore, the seat has at least one engagement element into which an engagement element of the interchangeable cutting insert engages. For this purpose, this engagement element is arranged on the side of the interchangeable cutting insert facing the neck. The number of engagement elements on the interchangeable cutting insert is in particular equal to the number of cutting edges on the interchangeable cutting insert. The two interlocking engagement elements offer two advantages: When the interchangeable cutting insert is placed on the neck for the first time or is rotated on the neck when a worn cutting edge is to be brought into a passive position in order to simultaneously move a previously unused cutting edge from a passive position to the active position, the engagement element gives the user haptic feedback as to when the interchangeable cutting insert has been positioned at the correct angle to the seat, so that the interchangeable cutting insert can now be clamped. This prevents improper installation.Secondly, the engagement element absorbs some of the forces acting on the interchangeable cutting insert transverse to the longitudinal axis, so that these do not have to be absorbed exclusively by a clamping device. This protects the interchangeable cutting insert from twisting.

[0018] In a preferred embodiment of the tool system, the at least one engagement element of the seat and the at least one engagement element of the interchangeable cutting insert are each a toothing. In another preferred embodiment of the tool system, the at least one engagement element of the seat and the at least one engagement element of the interchangeable cutting insert are each a side of a polygon. If the interchangeable cutting insert is angled relative to the longitudinal axis of the tool carrier, the interchangeable cutting insert can then be pulled towards the side surfaces at the level of the passive cutting edges when the clamping screw is turned, thus securely clamping the interchangeable cutting insert.

[0019] In yet another preferred embodiment of the invention, the seat and the interchangeable cutting insert each have exactly one engagement element. One of the engagement elements is concave, and the corresponding engagement element is convex. The interchangeable cutting insert is aligned via a point at which a passive cutting edge rests in the protective area.

[0020] The engagement elements of the interchangeable cutting insert can be supplied in an unmachined, sintered state. However, depending on requirements, the engagement elements can also be ground. The engagement elements on the seat are then adjusted accordingly.

[0021] The preferred clamping device is a clamping screw that extends through one end face of the insert into the seat. This clamping of the tool system at the end face has the advantage over clamping along the diameter axis of the tool holder that the neck of the tool holder is not unnecessarily weakened, enabling a more stable turning process and greater overhang lengths.

[0022] Furthermore, it is preferred that a coolant channel runs through a receiving area and the neck of the tool carrier and opens into at least one outlet opening on a circumferential surface of the neck. While coolant channels are generally desirable in such tool systems, they often cannot be realized by tensioning them along the carrier diameter axis, as this leaves insufficient space for the coolant channel in the neck. The tool system according to the invention, on the other hand, still has sufficient space in its neck to allow for the positioning of a coolant channel.

[0023] In a preferred embodiment of the tool system, it has an outlet opening facing the active cutting edge. This enables active cooling of the active cutting edge. In another preferred embodiment of the tool system, it has an outlet opening facing away from the active cutting edge. This enables passive cooling of the active cutting edge. Short description of the drawings

[0024] Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. Figure 1a shows an isometric view of a tool system according to an embodiment of the invention. Figure 1b shows a side view of the tool system according to Figure 1a . Figure 1c shows a side view of the tool system according to Figure 1a , which compared to the representation in Figure 1b was rotated 90° along its longitudinal axis. Figure 1dshows a detailed view Figure 1c . Figure 2a shows an isometric detailed view of the neck of a tool carrier of a tool system according to an embodiment of the invention. Figure 2b shows a view of the Figure 2a depicted neck of a tool carrier from its front side. Figure 3a shows a side view of an interchangeable cutting insert of a tool system according to an embodiment of the invention. Figure 3b shows an isometric view of the interchangeable cutting insert according to Figure 3a . Figure 3c shows a view of the interchangeable cutting insert according to Figure 3a from its back. Figure 4 shows an isometric exploded view of a tool system according to an embodiment of the invention. Figure 5 shows a view of a tool system according to an embodiment of the invention from its front side. Embodiments of the invention

[0025] A tool system according to a first embodiment of the invention in the assembled state is shown in the Figures 1a to 1dshown. The tool system has a tool holder 10 with a circular-cylindrical receiving area 11 and a circular-cylindrical neck 12, which in this case is made of steel. The receiving area 11 is intended to hold the tool system in a machine. The neck 12 carries an interchangeable cutting insert 20 with hard metal cutting edges on its front side. It has a smaller diameter than the receiving area 11 and is adapted to a diameter of a workpiece to be machined. A coolant channel runs through the receiving area 11 and the neck 12 and opens into an opening 13 in the neck 12. This opening 13 and an active cutting edge 21 of the interchangeable cutting insert 20 lie on a common straight line that runs parallel to the longitudinal axis L of the tool holder 10. A protective area 14, formed integrally with the receiving area 11 and the neck 12, projects from the neck 12.The length of the protective zone 14 along the longitudinal axis L corresponds to the length of the interchangeable cutting insert 20. The longitudinal axis of the interchangeable cutting insert 20 is inclined by an angle α of 2° relative to the longitudinal axis L of the tool holder 10. The angle β of the active cutting edge 21 to the longitudinal axis L of the tool holder 10 is therefore 88°.

[0026] In the Figures 2a and 2b The protective area 14 is shown in detail. This has two recesses 15 in order to accommodate two passive cutting edges of the interchangeable cutting insert 20. For one of these recesses 15, Figure 2aits side surface 16 can be seen. Since the seat 30 on the neck 12 on which the interchangeable cutting insert 20 rests is inclined by the same angle α as the interchangeable cutting insert 20 with respect to the longitudinal axis L of the tool holder 10, the side surface 16 is also angled with respect to the longitudinal axis L of the tool holder 10 in order to enable the cutting edge to be positioned therein to be received without it coming into contact with the seat 14. However, between the recess 16 and the seat 30, the interchangeable cutting insert 20 rests on the protective area 14 and is thus additionally stabilized. The seat 30 has engagement elements 31 in the form of a toothing with three teeth. In addition, a threaded bore 32 runs orthogonally through its center point. This bore is inclined by the angle α with respect to the longitudinal axis L of the tool holder 10.

[0027] As in the Figures 3a to 3cAs shown, the interchangeable cutting insert 20 has three cutting edges 21 to 23. In the assembled state of the tool system, which is shown in the Figures 1a to 1dAs shown, the first cutting edge 21 acts as the active cutting edge and the other cutting edges 22, 23 as passive cutting edges, which are surrounded by the protective area 14 and accommodated in its recesses 15. A circular-cylindrical opening 24 extends through the interchangeable cutting insert 20 along the longitudinal axis thereof, which opening has a countersink on its front side. On the side of the interchangeable cutting insert 20 opposite the front side, engagement elements 25 in the form of a toothing with three teeth are arranged. These are designed to engage with the engagement elements 31 of the seat 30. Both the engagement elements 25 of the interchangeable cutting insert 20 and the engagement elements 31 of the seat 30 are arranged at an angle of 120° to one another. If the interchangeable cutting insert 20 is placed on the seat 30 in such a way that the teeth 25, 31 engage with one another, the first cutting edge 21, for example, is thereby engaged in the Figures 1a to 1dshown position.

[0028] The Figures 4 and 5 show how the interchangeable cutting insert 20 can be clamped to the seat 30 using a clamping screw 40. The clamping screw has a head 41 and a screw shaft 42. After the interchangeable cutting insert 20 has been positioned on the seat 30 so that the teeth 25, 31 engage with each other, the clamping screw 40 is guided through the opening 24 of the interchangeable cutting insert 20 and the screw shaft 42 is screwed into the threaded bore 32 of the seat 30. The head 41 of the clamping screw 40 is countersunk into the recess of the opening 24.

[0029] When the first cutting edge 21 is worn, it is sufficient to loosen the clamping screw 40 sufficiently so that the interchangeable cutting insert 20 can be removed from the seat 30 along the clamping screw 40, which is angled by an angle α of 2° from the longitudinal axis L of the tool holder 10, until the cutting edges 21 to 23 protrude beyond the protective area 14. The interchangeable cutting insert 20 can then be rotated by 120° and subsequently clamped again to the seat 30 using the clamping screw 40. This moves one of the other two previously passive cutting edges 22, 23 into the active position and positions the worn cutting edge 21 in one of the recesses 15 of the protective area 14. Removing the tool holder 10 from the machine is not necessary for this purpose.

[0030] In a second embodiment of the tool system, a projection in the shape of an equilateral triangle is arranged on the seat 30 instead of the toothing. Each side of the triangle forms an engagement element 31. On the side of the interchangeable cutting insert 20 opposite the end face, a recess is formed, which also has the shape of an equilateral triangle. Its sides also function as engagement elements 25, into which the engagement elements 31 of the seat 30 engage.

[0031] In a third embodiment of the tool system, the seat 30 has a hemispherical concave recess as the engagement element 31 instead of the toothing. On the side of the interchangeable cutting insert 20 opposite the end face, a hemispherical convex projection is arranged as the engagement element 25, which engages with the engagement element 31 of the seat 30.

Claims

1. Tool system, having a tool carrier (10) with a neck (12) and an interchangeable cutting insert (20) arranged on a seat (30) of the neck (12), wherein the neck (12) has a protection area (14), which projects over the seat (30) along the longitudinal axis (L) of the tool carrier (10) and it surrounds all the edges (22, 23) of the interchangeable cutting insert (20) except one edge (21), characterised in that the seat (30) has at least one engaging element (31) into which at least one engaging element (25) of the interchangeable cutting insert (20) engages.

2. Tool system according to claim 1, characterised in that the protection area (14) at least extends up to a ground area of the edges (22, 23).

3. Tool system according to claim 1 or 2, characterised in that a length of the protection area (14) is identical to a length of the interchangeable cutting insert (20), along the longitudinal axis (L).

4. Tool system according to one of claims 1 to 3, characterised in that the protection area (14) is designed as a circular-shaped projection, which has a cavity (15) for each edge (22, 23) surrounded by it, in which the respective edge (22, 23) is received.

5. Tool system according to claim 4, characterised in that a side surface (16) of each cavity is at an angle in comparison to the longitudinal axis (L).

6. Tool system according to one of claims 1 to 5, characterised in that the interchangeable cutting insert (20) is at an angle in comparison to the longitudinal axis (L).

7. Tool system according to one of claims 1 to 6, characterised in that the protection area (14) is partially placed on the interchangeable cutting insert (20).

8. Tool system according to one of claims 1 to 7, characterised in that a clamping screw (40) runs through an end face of the interchangeable cutting insert (20) into the seat (30).

9. Tool system according to one of claims 1 to 8, characterised in that a coolant channel runs through a receiving region (11) and the neck (12) of the tool carrier (10) and flows into at least one discharge port (13) at a lateral surface of the neck (12).