CUTTING TOOL

Description

[0001] The present invention relates to a cutting tool in which the cutting insert can be fixed to a base body via a clamping claw.

[0002] Such a cutting tool is shown, for example, in EP 0 381 924 A2. EP 0 381 924 A2 proposes using a clamping claw to fix a cutting attachment to a base body of the cutting tool. This clamping claw is pressed against the base body by means of a clamping screw. A projecting end section presses against the cutting attachment, thereby clamping the cutting attachment flat against the bottom surface of a recess in the base body. The disadvantage of this arrangement is that fine adjustment of the cutting attachment is not possible.

[0003] In a comparable manner, which develops this subject matter further, DE 101 44 923 A1 discloses a cutting tool in which a cutting insert, in particular an indexable insert, is positively received in a pocket of a clamping claw whose position is adjustable in the axial and radial directions relative to a base body of the cutting tool. The clamping claw clamps the cutting insert against a support surface on the base body. With an overall space-saving design, the cutting tool allows for relatively simple fixation and position adjustment of a cutting insert via the clamping claw on the base body. To change the cutting insert, the clamping claw must be loosened or removed. Changing the cutting insert therefore always requires a readjustment of the position of the clamping claw.

[0004] US 5 217 333 A, US 3 332 130 A, and EP 0 126 432 A1 each show a cutting tool with a base body extending along a longitudinal central axis and a cutting insert held on the base body in an axially and / or radially adjustable position, which can be clamped by means of a clamping claw. The cutting insert is held by a clamping holder fixed to the base body in a positionally adjustable manner, which can be clamped against the base body by the clamping claw pressing against the cutting insert. US 4 353 669 A and WO 2014 / 041130 A1 each show a cutting tool according to the preamble of claim 1.

[0005] The invention is based on the cutting tool of US 4 353 669 A and is based on the object of developing a cutting tool of the type described at the outset in such a way that, when changing the cutting insert, the arrangement of a cutting insert in a predefined position on the base body is possible without any further adjustment.

[0006] This object is achieved by a cutting tool having the features of claim 1. Preferred developments are the subject of dependent claims.

[0007] Analogous to the cutting tool known from DE 101 44 923 A1, a cutting tool according to the invention, which can be designed, for example, as a drilling, turning, milling, reaming tool or the like, has a base body extending along a longitudinal central axis and a cutting insert which is held on the base body in an axially and / or radially adjustable position and which can be fixed by means of a clamping claw.

[0008] The base body can, in a manner known per se to those skilled in the art, have a shank section with a so-called HSK (short for hollow shank taper) shank for coupling to a module of a modular tool system or to a machine spindle. In this case, the base body can be functionally divided into the shank section and an axially adjoining cutting part, with the cutting insert arranged on the cutting part.

[0009] In contrast to the cutting tool known from DE 101 44 923 A1, in the cutting tool according to the invention, the cutting insert is not clamped directly against the base body via a clamping claw, but rather via a clamping holder that is positionally adjustable and fixed to the base body. Because the axial and / or radial position adjustment of the cutting insert is thus carried out indirectly via the clamping holder that is positionally adjustable and arranged on the base body, the function of the clamping claw is limited to clamping the cutting insert (via the clamping holder) to the base body. This makes it possible to maintain a position adjustment of the clamping holder once it has been carried out, even if the clamping claw is loosened or released to change the cutting insert.The cutting tool according to the invention is therefore characterized by the fact that the function of axial and / or radial position adjustment and securing the clamping holder to the base body, on the one hand, and the function of clamping the cutting insert relative to the base body, on the other, are solved separately. The cutting insert can therefore be changed without having to readjust its position. The clamping claw provides the clamping holder, which is arranged independently of the clamping claw on the base body, with additional force-locking to the base body.

[0010] According to the invention, the base body has a receiving pocket that accommodates the clamp holder in a direction transverse to the longitudinal center axis and captively in the axial direction. A receiving pocket designed in this way contributes to easy installation of the clamp holder on the base body and thus to a reduction in setup time.

[0011] In a preferred embodiment, the clamping claw is screwed to the base body by a clamping screw that penetrates the clamping holder. The clamping screw penetrates a hole in the clamping holder with sufficient play to allow the clamping holder to be moved within limits relative to the clamping screw for axial and / or radial position adjustment. When the clamping screw is tightened, it presses the clamping claw onto the cutting insert, which is then pressed onto the clamping holder, causing the latter to be pressed onto a support surface on the base body. The clamping claw, cutting insert, and clamping holder are thus pressed against the base body by the clamping screw, thereby fixing them to the base body. As will be explained in more detail later, the clamping claw can be provided with a countersink, which interacts with a conical surface on the head of the clamping screw and always clearly positions the clamping screw relative to the clamping claw.This ensures a reproducible alignment of the clamping claw relative to the clamping screw, which is positioned by screwing onto the base body. This action allows the clamping claw to clamp the cutting insert against the clamping holder.

[0012] A further advantage of using the clamping claw is that the cutting insert, such as a cutting insert, especially an indexable insert, no longer requires a central through-hole to secure it to the base body. This allows even the smallest cutting inserts to be used, which would otherwise be weakened by a central opening. The stress on the cutting insert, especially an inserted cutting insert, can be achieved in such a way that it rests against the clamp holder over a large area. This minimizes contact stresses, which is particularly advantageous when extremely hard cutting materials, such as cemented carbide, ceramic materials, or cermet materials, are used.

[0013] The receiving pocket can form a preferably flat support surface of the receiving pocket, extending in the direction of displacement of the clamping holder, against which the clamping holder can be clamped over a large area. The direction of displacement can be parallel to a radial and / or axial direction or, in vectorial terms, can be understood as the addition of directional vectors, one of which runs radially and one axially. However, the displacement does not have to take place in a plane in which the longitudinal center axis runs, but can also take place in a plane parallel to the plane spanned by a radial vector and the longitudinal center axis. If the clamping holder rests flatly on the support surface on the base body side, the stresses in the base body are reduced, so that less distortion can be expected. Overall, these measures can further optimize the flow of forces from the functional cutting edge to the carrier body.

[0014] In a preferred embodiment, the base body can further comprise a guide opening that guides the clamping claw linearly toward the clamp holder, e.g., by means of a positive fit. The positive guidance of the clamping claw in the guide opening ensures that the clamping claw can only be removed from the guide opening in one direction, i.e., the guide ring direction. Even if the clamping screw is completely loosened for disassembly, the clamping claw can therefore be held in the guide opening in a direction transverse to the guide ring direction.

[0015] If the cutting tool has both the aforementioned receiving pocket and the guide opening that linearly guides the clamping claw, it is particularly advantageous if the extension direction of the guide opening is inclined relative to the support surface of the receiving pocket in such a way that the clamping claw presses the clamping holder via the cutting insert against a stop on the base body. This stop on the base body can be an adjustment element, e.g., a set screw, of an adjustment device provided on the base body that enables axial and / or radial position adjustment of the clamping holder on the base body. By appropriately selecting the angle of inclination of the extension direction of the guide opening relative to the support surface of the receiving pocket, a force component can be generated when clamping between the clamping claw and the clamping holder, which presses the clamping holder against the aforementioned stop on the base body.

[0016] The measures described above contribute to a high positional accuracy of the clamp holder on the base body and easy assembly.

[0017] The clamp holder can be secured to the base body (after position adjustment) using a locking device that is independent of the clamping claw and integrated into the base body. This locking device can consist of a clamping screw screwed to the base body, which presses the clamp holder against the base body. As already mentioned, the clamp holder's clamp-independent locking ensures that the clamp holder retains its axially and / or radially adjusted position in the base body even when the clamping claw is released. Once the clamp holder is secured in this way, the cutting insert, such as a cutting insert, can be removed from the clamp holder by loosening or releasing the clamping claw, without having to remove the clamp holder from the base body. This makes it possible to change only the cutting insert if necessary, without having to subsequently readjust the entire tool.The use of a clamping screw to secure the clamp holder to the base body helps to keep the overall cost of the cutting tool low.

[0018] To ensure the most precise positioning of the cutting insert in the axial and / or radial directions on the base body, the cutting insert can be fixed in position relative to the base body in a cutting insert seat on the toolholder, e.g., by means of a positive fit. If the cutting insert is fixed in position on the toolholder, it can be easily removed and reinstalled, especially if the toolholder is fixed to the base body.

[0019] Particularly in this embodiment, the cutting insert, as already mentioned, can expediently be formed by a cutting insert, in particular an indexable insert. Such cutting inserts are well known in machining as components of corresponding tools.

[0020] For the axial and / or radial position adjustment of the clamping holder, the cutting tool according to the invention can have an adjustment device integrated into the clamping holder for adjusting the radial and / or axial position of the clamping holder relative to the longitudinal center axis of the base body. For example, the adjustment device on the clamping holder side consists of an adjusting screw screwed to the clamping holder and pressing against the base body. The reduction of the screw thread relative to the displacement of the adjusting screw in its axial direction and the additional possibility of adjusting the wedge angle of the tip of the adjusting screw and the clamping holder enable precise adjustment.

[0021] Alternatively or in addition to the aforementioned adjustment device provided on the clamping holder side, the cutting tool can have an adjustment device integrated into the base body for adjusting the radial and / or axial position of the clamping holder relative to the longitudinal center axis. Such an adjustment device can consist of a set screw screwed to the base body and pressing against the clamping holder. This adjustment device also ultimately serves to shorten changeover times by ensuring the defined mounting of the clamping holder in the base body.

[0022] The invention will be explained below with the aid of the accompanying drawings based on a preferred embodiment. The drawings show: Fig. 1 a partially longitudinally sectioned view of a cutting tool according to the invention; Fig. 2 a perspective side view of the cutting tool according to the invention; Fig. 3a plan view of an arrangement formed from a clamping holder, a cutting insert and a clamping claw, which is arranged in a positionally adjustable manner on a base body of the cutting tool; Fig. 4 a side view of the Fig. 3 arrangement shown, and Fig. 5 a front view of the Fig. 3 arrangement shown.

[0023] The Fig. 1 and 2 The cutting tool shown, which can be used for turning, drilling or milling, has a base body 4, which is only partially shown in the figures and which extends along a rotational or longitudinal center axis 9. The base body 4 is, as can be seen from the Figures 1 and 2recognizably formed from a substantially rotationally symmetrical body. Although not shown here, the base body 4 may, in a manner known per se to those skilled in the art, have a shank portion with, for example, an HSK (hollow shank taper) shank for coupling the cutting tool to a drive spindle of a machine tool. Fig. 1 and 2 show that the base body, based on the model of the cutting tool known from DE 101 44 923 A1, has a central receiving opening 47 for receiving a further cutting tool not shown here, e.g. a reamer.

[0024] In addition, one can see Fig. 1 and 2 an arrangement described in more detail below, which consists of a cutting insert (here in the form of a cutting plate 1), a clamping holder 2 and a clamping claw 3 and is arranged on the base body in a positionally adjustable manner.

[0025] In the preferred embodiment, the cutting insert is designed as a cutting plate 1, in particular as an indexable cutting plate. In the embodiment shown, the cutting plate 1 is arranged in a fixed position in a cutting insert seat 23 on a clamping holder 2 by means of a positive locking mechanism.

[0026] The clamp holder 2 has an outer shape similar to a cuboid. As can be seen particularly in the Figures 1 and 3 The clamp holder 2 is almost completely cuboid-shaped in the front (left in the figures) and rear (right) sections, with the rear section having a greater thickness than the front section due to a wedge-shaped middle section. On the rear side (right in Fig. 1), the clamp holder 2 has a trough-shaped recess 24 in which a pressure piece of a clamping screw 8 (described later) is arranged. In a modification not shown, the clamp holder 2 can be wedge-shaped, for example, over its entire length.

[0027] The cutting insert 1 is held in a fixed position in a cutting insert seat 23 on the clamping holder 2 by a positive locking mechanism. This ensures that the cutting insert 1 is firmly fixed relative to the clamping holder 2. The clamping claw 3 is pressed onto the cutting insert 1 by means of the clamping screw 5 in order to clamp the cutting insert 1 against the clamping holder 2.

[0028] The base body 4 has a clamping thread 41 for the clamping screw 4, a receiving pocket 42 for the clamping holder 2 (with a flat support surface 45 for the clamping holder), a threaded hole 43 for a set screw 7 (explained later), a threaded hole 44 for a clamping screw 8 (explained later), a central receiving opening 47 for another tool and a guide opening 46 for the clamping claw 3. As can be seen from the Figures 1 and 2 As can be seen, the clamping claw 3 can be moved in a linear direction (in the Figures 1 and 2 from above) into the base body and clamped against it using the clamping screw 5.

[0029] The clamp holder 2 is accommodated in the receiving pocket 42 in the base body 4, which accommodates the clamp holder 2 in such a way that it can be moved in a direction transverse to the longitudinal center axis 9 (in the Fig. 1perpendicular to the plane of the drawing) and is adjustable in both radial and axial directions. An adjusting screw 6 (explained later) adjusts the clamp holder against the base body 4 in a direction transverse to the longitudinal center axis 9 or in the radial direction of the base body 4.

[0030] The receiving pocket 42 in the base body 4 is designed to resemble the outer shape of the clamp holder 2, so that the clamp holder 2 can be inserted in the direction transverse to the longitudinal center axis 9. Due to the two cuboid sections and the wedge-shaped central section connecting them, the clamp holder 2 can be displaced axially to a limited extent in the receiving pocket, but is arranged in a captive manner. Analogous to the previously explained receiving pocket for the clamp holder 2, a guide opening for the clamping claw 3 is also provided in the embodiment. The guide opening merges into the receiving pocket 42 for the clamp holder 2 and guides the clamping claw 3 in a straight line towards the clamp holder 2.

[0031] A clamping screw 8 screwed into a threaded bore 44 in the base body 4 clamps the clamp holder 2 against the base body 4 after an axial and / or radial position adjustment has been carried out. The clamping screw 8 is designed as a grub screw.

[0032] The Figures 1 to 5 show the clamping claw 3. As can be seen from the figures, the outer shape of the clamping claw 3 forms a prismatic cuboid, which on one side (right in the Figures 1 , 3 and 4 ) ends in a half cylinder around a through hole 31 for the clamping screw 5, and on its other side (left in the Figures 1 to 4 ) into a bevelled prismatic surface. In addition, the clamping claw tapers in the top view of the Fig. 3 to the other side. The shown shape has the advantage of high stability with a comparatively small footprint; however, the clamping claw can also be designed differently depending on the tool's specific requirements, as long as it reliably transfers the force exerted by the clamping screw 5 to the cutting insert 1 and holds it securely.

[0033] In the embodiment, the clamping claw 3 is pressed onto the clamping holder 2 via the cutting plate 1 by means of a clamping screw 5. As shown in the Fig. 1 As can be seen, the clamping screw 5 passes through the through hole 31 in the clamping claw 3 and another through hole 21 in the clamping holder 2 in order to be screwed into the clamping thread 41 in the base body 4. The clamping claw 3 presses against the cutting plate 1. The through hole 31 has, as in Fig. 1 a conical countersink is clearly visible, so that the clamping screw 5 is centered in the clamping claw 3 when tightened. As can be seen from Fig. 1 As can be seen, the through holes 21, 31 and the threaded hole 41 are inclined against the radial direction of the base body in such a way that the clamping screw 5 clamps the clamping claw 5 slightly obliquely in such a way that it is on the front side ( Fig. 1: left) further down and rests on the cutting plate 1. This results in a (not shown in the figure) main force component, which presses the clamping claw 3 in the radial direction onto the cutting plate 1 and thereby the cutting plate 1 onto the clamp holder 2 and the clamp holder 2 onto the support surface 45 in the base body 4, at the support point of the clamping claw 3 on the cutting insert 1, a (smaller) force component FJ, which presses the cutting plate 1 into the cutting insert seat on the clamp holder 2 and also presses the clamp holder 2 in the axial direction against the adjusting screw 7. For clarity, this force component is shown in the Fig. 1 not at the place of its origin, but in the clamp holder 2 on which it acts.

[0034] Adjusting screws 6 and 7 are provided as adjustment devices for axial and / or radial position adjustment.

[0035] The adjusting screw 7 is screwed into the threaded hole 43 in the base body 4 and presses against a corresponding rear wedge surface 22 of the clamp holder 2. If the adjusting screw 7 is screwed in further or advanced, it presses the clamp holder 2 and the cutting insert 1 connected to it forwards over the wedge surface 22 (in the Fig. 1 to the left). As Fig. 3 As can be seen, the wedge surface 22 is also designed skewed on the clamp holder 2 so that when the adjusting screw 7 is adjusted, the clamp holder 2 simultaneously also moves into the receiving pocket 42 (in Fig. 1 vertically into the drawing plane, in Fig. 3upwards). As a result, the clamp holder 2 is clamped, on the one hand, in the receiving pocket 42 and, on the other hand, against the adjusting screw 6. The adjustment into the receiving pocket 42 described above can be restricted via the adjusting screw 6. This adjusting screw 7 serves as an above-mentioned stop on the base body side, which absorbs the above-mentioned force FJ.

[0036] After the axial alignment of the clamp holder 2, the adjusting screw 6 is screwed in by the adjusting screw 7 until it fixes the clamp holder 2 in the radial direction by pressing against a radial stop surface in the receiving pocket 42. This displaces or clamps the clamp holder 2 in the radial direction against the base body 4 and the adjusting screw 7.

[0037] After the above-explained axial and / or radial position adjustment using the adjusting screws 6 and 7, the clamping holder 2 is secured by means of the clamping screw 8, which presses against the bottom of the trough-shaped recess 24 in the clamping holder 2 via a pressure piece. In this state, the cutting insert 1 can be clamped by means of the clamping claw 3, whereby the clamping holder 2 is additionally clamped against the base body.

[0038] While the adjusting screws 6 and 7, as explained above, determine the alignment of the clamping holder 2 and thus of the cutting insert 1, the clamping screw 5 in the clamping claw 3 centers it when tightened via a countersink in the upper section of the through hole 31 in the clamping claw 3. Through this centering and the additional positive locking in the guide opening, the position of the clamping claw 3 in the base body 4 is clearly defined. In addition, the clamping screw 5 penetrates Fig. 1visible with comparatively large clearance through hole 21 in the clamping holder 2. Therefore, the clamping holder 2 can be aligned without interference by the clamping screw 5, and then the clamping screw 5 can be easily tightened once the clamping holder and the cutting insert are in the desired position. By tightening, the clamping claw 3 clamps the clamping holder 2 against the base body 4.

[0039] As can be seen from the above description and the Fig. 1As can be seen, the embodiment shown here results in a static overdetermination of the fixing of the clamping body 2 and the cutting insert 1 arranged therein in a fixed position relative to the base body 4. Therefore, if necessary, the clamping screw 5 (and thus the clamping claw 3), the adjusting screw 6 or the adjusting screw 7 can be loosened without changing the position of the cutting insert 1, because the clamping holder continues to be held securely by the clamping screw 8. Conversely, the position of the cutting insert 1 does not change if the clamping screw 8 is loosened, while the clamping screw 5 and both adjusting screws 6 and 7 remain unchanged.

[0040] Fig. 2 shows a perspective side view of the cutting tool according to the invention. In Fig. 2 can be seen more clearly than in Fig. 1The receiving opening 47 for any additional tools and, due to the perspective view, the shape of the clamping claw 3 and the associated guide opening can be seen. As can be seen from this figure, the clamping claw 3 can be Fig. 2 shown embodiment from above, namely in the direction of the axis of the clamping screw 5, into the guide opening. If the clamping claw 3 and the associated guide opening, as even better Figs. 3 and 5 recognizable, furthermore, tapers from the location of the through hole 31 for the clamping screw 5 towards the support on the cutting insert, the clamping claw 3 can essentially only move in one direction, namely the axial direction of the clamping screw, relative to the base body 4.

[0041] Fig. 3shows a plan view of the arrangement formed by the cutting insert 1, the clamping holder 2, the clamping claw 3 and the clamping, setting and clamping screws 5 to 8, which is arranged in a positionally adjustable manner on a base body of the cutting tool, i.e. an arrangement of all parts accommodated in the base body 4, wherein the base body 4 itself is omitted for simplification. Fig. 3 It is easier to see that the already mentioned Fig. 1 The wedge surface 22 mentioned runs obliquely to the longitudinal axis of the base body 4 and the clamp holder 2 aligned parallel thereto. As a result, by screwing in ("adjusting") the adjusting screw 7, the clamp holder 2 can be adjusted radially to the base body 4, namely in Fig. 3 upwards, and at the same time (cf. Fig. 1 ) forward, i.e. into the Figures 1 to 3to the left. As soon as the adjusting screw 7 protrudes into the pocket of the clamp holder 2 defined by the adjustment surface 22, the clamp holder 2 is also secured against falling out by this screw 7 and is adjusted by it.

[0042] Fig. 4 shows a side view of the Fig. 3 shown arrangement, and Fig. 5 reveals a front view of the Fig. 3 arrangement shown. Fig. 4 To clarify the functionality, shows the cutting plate 1, the clamp holder 2, the clamping claw 3 and the clamping, adjusting and clamping screws 5 to 8 in the assembled state in a view from the same side as Fig. 1 , but uncut, while the base body 4 is similar to the one above for simplification Fig. 3 explained is omitted. In contrast to the Fig. 1 is therefore also, for example, the head of the (in Fig. 1 cut) adjusting screw 6 can be seen. As can be seen from Fig. 4As can be seen, the adjusting screw 6, like the adjusting screw 7 and clamping screw 8 discussed above, is designed as a grub screw in this embodiment.

Claims

1. Cutting tool having a base body (4) extending along a longitudinal central axis (9) and a cutting insert (1) held on the base body (4) in a radially adjustable position, the cutting insert (1) being clampable by means of a clamping claw (3) and being held by a clamping holder (2) fixed to the base body (4) in a positionally adjustable manner, wherein the clamping holder (2) is clampable against the base body (4) by the clamping claw (3) pressing against the cutting insert (1), the base body (4) having a receiving pocket (42) which receives the clamping holder (2) in a manner such that it can be displaced in a direction transverse to the longitudinal central axis (9), and the receiving pocket (42) receives the clamping holder (2) in a captive manner in the axial direction, characterized in that the cutting insert (1) is held on the base body (4) in an axially adjustable position.

2. Cutting tool according to claim 1, characterized in that the clamping claw (3) is screwed to the base body (4) by means of a clamping screw (5) penetrating the clamping holder (2).

3. Cutting tool according to claim 1 or 2, characterized in that the clamping holder (2) is clampable flat against a preferably flat bearing surface (45) of the receiving pocket (42), the bearing surface (45) extending in the direction of displacement of the clamping holder (2).

4. Cutting tool according to one of the preceding claims, characterized in that the base body (4) has a guide opening (46) which guides the clamping claw (3) linearly with respect to the clamping holder (2).

5. Cutting tool according to claims 3 and 4, characterized in that the extending direction of the guide opening (46) is inclined with respect to the bearing surface (45) of the receiving pocket (42) in such a way that the clamping claw (3) presses the clamping holder (2) against a stop on the base body side.

6. Cutting tool according to claim 4 or 5, characterized in that the guide opening (46) guides the clamping claw (3) in a form-fitting manner.

7. Cutting tool according to one of the preceding claims, characterized by a fixing device (8) for fixing the clamping holder (2) to the base body (4), the fixing device (8) being independent of the clamping claw (3) and integrated into the base body (4).

8. Cutting tool according to claim 7, characterized in that the fixing device (8) is formed by a clamping screw (8) which is screwed to the base body (4) and presses the clamping holder (2) against the base body (4).

9. Cutting tool according to one of the preceding claims, characterized in that the cutting insert (1) is arranged in a cutting insert seat (23) on the clamping holder (2) such as to be fixed in position relative to the clamping holder (2).

10. Cutting tool according to one of the preceding claims, characterized in that the cutting insert is formed by a cutting plate (1), in particular an indexable insert.

11. Cutting tool according to one of the preceding claims, characterized by an adjusting device (6) integrated into the clamping holder (2) for adjusting the radial and / or axial position of the clamping holder relative to the longitudinal central axis (9).

12. Cutting tool according to claim 11, characterized in that the adjusting device (6) is formed by an adjusting screw (6) screwed to the clamping holder (2) and pressing against the base body (4).

13. Cutting tool according to one of the preceding claims, characterized by an adjusting device (7) integrated into the base body (4) for adjusting the radial and / or axial position of the clamping holder (2) relative to the longitudinal central axis (9).

14. Cutting tool according to claim 13, characterized in that the adjusting device (7) is formed by an adjusting screw (7) screwed to the base body (4) and pressing against the clamping holder (2).