Cutting insert and modular rotary tool

Abstract

Cutting insert (4) for a modular rotary tool (2, 4) which extends along a rotation axis (24) from a first end (12) to a second end (14), wherein - the first end (12) is a coupling designed for reversible connection to a carrier (2), - the second end (14) has an end face (20) on which a plurality of main cutting edges (16, 18) are formed, namely at least one primary main cutting edge (16) and at least one secondary main cutting edge (18) and - a primary chip groove (28) is assigned to the primary main cutting edge (16) and a secondary chip groove (30) is assigned to the secondary main cutting edge (18), characterized in that the primary chip groove (28) and the secondary chip groove (30) have different rake angles (α, β) and that the secondary chip groove (30) opens into the primary chip groove (28).

Description

Background of the invention

[0001] The invention relates to a cutting insert for a modular rotary tool. The invention also relates to a corresponding modular rotary tool.

[0002] A modular rotary tool, as described, for example, in US 2021 / 0299763 A1 or US 2019 / 0054548 A1, is a rotary tool in which a cutting insert or a cutting head is reversibly detachably attached to a carrier.

[0003] US 2021 / 0299763 A1 and US 2019 / 0054548 A1 each describe modular rotary tools which are designed as drilling tools or drills for short.

[0004] The drill in US 2021 / 0299763 A1 has, in addition to a main cutting edge, an additional cutting edge that is shorter than the main cutting edge. According to one design variant, the drill has two corresponding main cutting edges and two corresponding secondary cutting edges.

[0005] DE 10 2010 012 963 A1 describes a drill bit for fiber-reinforced materials. A peripheral edge is formed axially following the main cutting edges, defining a transverse groove or constriction. The peripheral edge serves to cut off fiber pieces from the fiber-reinforced material. Object of the invention

[0006] Proceeding from this, the object of the invention is to provide an advantageously designed cutting insert for a modular rotary tool and an advantageously designed modular rotary tool. Solution to the task

[0007] This object is achieved according to the invention by a cutting insert having the features of claim 1 and by a modular rotary tool having the features of claim 14. Preferred developments are contained in the dependent claims. The advantages and preferred embodiments cited with regard to the cutting insert are also transferable to the modular rotary tool, and vice versa.

[0008] The cutting insert according to the invention is designed for a modular rotary tool and is typically configured in the manner of a cutting head. Furthermore, the cutting insert is preferably formed as a single piece, in particular monolithic. Depending on the application, the cutting insert is also designed for machining workpieces made of carbon fiber reinforced plastic (CFRP).

[0009] The rotary tool according to the invention is in turn preferably designed as a drilling tool or, in short, a drill and independently thereof has a carrier and the cutting insert, i.e. the cutting insert according to the invention, wherein the cutting insert is reversibly detachably fastened or mounted on the carrier.

[0010] Since the connection between the cutting insert and the carrier is designed to be reversibly detachable, the cutting insert and carrier can advantageously be replaced independently of each other. It is important to note that when using a rotary tool, the cutting insert typically experiences significantly more wear than the carrier, so the cutting insert usually has a significantly shorter service life or life expectancy than the carrier.

[0011] Independently of this, the cutting insert extends along a rotational axis from a first, coupling-side end to a second, end-face end, wherein the first end forms a coupling for reversible connection to the carrier. The second end, which expediently forms an end face of the cutting insert and in particular of the rotary tool, further forms a plurality of main cutting edges, namely at least one primary main cutting edge and at least one secondary main cutting edge.

[0012] Each main cutting edge is assigned a chip groove, so that the cutting insert forms at least two chip grooves. A primary chip groove is assigned to the primary main cutting edge, and a secondary chip groove is assigned to the secondary main cutting edge. "Assigned" in this application means that the corresponding chip groove adjoins the assigned main cutting edge, in particular directly.

[0013] Furthermore, the primary chip flute and the secondary chip flute have different rake angles. The primary chip flute defines a primary rake angle, and the secondary chip flute defines a secondary rake angle. The two rake angles are selected so that the secondary chip flute flows into the primary chip flute. In this way, the number of chip flutes starting from the face of the cutting insert in the direction of the coupling is advantageously reduced, and in particular halved. The rake angle is generally understood to mean the orientation / inclination of the chip flute relative to the rotational axis - viewed in a side view of the cutting insert / rotary tool from a radial perspective.

[0014] In an advantageous development, the carrier of the rotary tool also has a carrier chip groove. The cutting insert and carrier are preferably designed such that, when the cutting insert is mounted on the carrier, the primary chip groove merges into the carrier chip groove. In this case, the carrier chip groove and primary chip groove preferably have identical or essentially identical chip angles, at least at the transition, and in particular also essentially identical cross-sections. For the secondary chip groove, however, no continuation is preferably formed on the carrier. Thus, during operation of the rotary tool, i.e. the modular rotary tool, chip material that is removed via the secondary chip groove is removed via the same carrier chip groove as chip material that is removed via the primary chip groove.

[0015] The chips generated by the primary and secondary main cutting edges are therefore transported away together via the carrier chip flutes.

[0016] The special design of the cutting head has the particular advantage that it can also be used with conventional carriers.

[0017] Depending on the application, different cutting inserts can be used for different cutting requirements with just one carrier. Therefore, no adaptation of existing carriers to the cutting insert according to the invention is necessary.

[0018] Depending on the application, the primary rake angle and the secondary rake angle are selected such that the ratio of the secondary rake angle to the primary rake angle is in the range of 1.5 to 3.0. Furthermore, the value is preferably in the range of 1.8 to 2.7.

[0019] Independently of this, depending on the application, a primary rake angle with a value in the range of 15° to 45° is specified. More preferably, the value is in the range of 20° to 40°, for example, 30°.

[0020] For the secondary rake angle, a value is advantageously specified that lies between 45° and 70°. More preferably, the value lies between 50° and 70°, for example, 60°.

[0021] Also typical are design variants in which the primary chip groove and the secondary chip groove not only have different rake angles, but also different cross sections, in particular different chip volumes. The chip volume of a chip groove is understood here to be a cross-sectional area of ​​the chip groove perpendicular to the axis of rotation. The primary chip groove is preferably wider than the secondary chip groove, i.e. the primary chip groove has a higher chip volume. The width of the primary chip groove usually has a value which, based on the width b of the secondary chip groove, is in the range 1.2 b to 3.0 b and in particular in the range 1.5 b to 2.5 b. The width of a chip groove is understood to be the distance between opposite wall areas of the chip groove.

[0022] It is also expedient if the secondary main cutting edge is shorter than the primary main cutting edge. The secondary main cutting edge typically extends only over an outer radial area. The primary main cutting edge, on the other hand, usually extends to the rotation axis or at least to a chisel edge or a front-end tip of the cutting insert. Preferably, both the primary and secondary main cutting edges each extend to a radially outer cutting edge, with the cutting edges being arranged on a common cutting circle.

[0023] Furthermore, it is advantageous if the secondary main cutting edge has an outer end and an inner end, viewed in the radial direction, which is spaced from the rotation axis. The distance between the inner end and the rotation axis, based on a cutting insert diameter D, preferably has a value in the range of 0.1 D to 0.4 D. The cutting insert diameter D forms a nominal diameter and corresponds to twice the radius of an outermost cutting corner. The value of the distance is preferably in the range of 0.2 D to 0.3 D.

[0024] The previously described shorter design of the secondary main cutting edge compared to the primary main cutting edge is preferably realized by a recess. The recess forms, in particular, a type of depression, which is designed, for example, in the manner of a groove. This means that this recess is recognizable as a depression, at least when viewed from above on the end face.

[0025] The cutting insert preferably has at least one cooling channel, wherein the cooling channel preferably opens into the aforementioned recess. Further preferably, the recess transitions into the primary chip groove on the one hand and the secondary chip groove on the other, so that a coolant conveyed via the cooling channel toward the end face can advantageously be distributed via the recess to the primary chip groove and the secondary chip groove.

[0026] In the case of most design variants, the cutting insert forms not only one primary main cutting edge, but two primary main cutting edges, with the two primary main cutting edges being connected to each other in particular via a cross cutting edge.

[0027] If two primary cutting edges are implemented, the cutting insert preferably forms two secondary cutting edges, with each primary cutting edge being assigned a secondary cutting edge. Primary cutting edges and secondary cutting edges alternate in the circumferential direction.

[0028] The cutting insert and in particular the modular rotary tool is preferably designed to be rotationally symmetrical, in particular in such a way that congruence is achieved when rotating around the rotation axis by 180°.

[0029] Other typical design variants include those in which the cutting insert, and in particular the rotary tool, is designed for a rotational or rotary direction. The term "subsequent" then refers to a sequence of positions that results when viewed opposite to the specified direction of rotation.

[0030] Also advantageous are designs in which two primary main cutting edges and two secondary main cutting edges are formed, in which a primary chip groove is assigned to each primary main cutting edge and a secondary chip groove is assigned to each secondary main cutting edge, and in which, in particular, each secondary chip groove opens into the primary chip groove which is assigned to the primary main cutting edge trailing the secondary chip groove.

[0031] Typically, each secondary main cutting edge is shorter than the primary main cutting edges, with each secondary main cutting edge preferably being shorter by means of a clearance. As a result, two clearances are preferably formed.

[0032] Furthermore, each of these clearances preferably forms a connection between a secondary chip groove and the primary chip groove of the trailing primary main cutting edge, at least when viewed from the front side of the cutting insert, wherein the connection is typically designed in the manner of a groove. A cooling channel preferably opens into each of these two connections, wherein, according to at least one embodiment, the cutting insert forms exactly two cooling channels.

[0033] Furthermore, each primary cutting edge is conveniently followed by a primary flank, in particular a front-end primary flank. Typically, each primary flank tapers at least partially into the trailing secondary chip flute.

[0034] The cutting insert, and in particular its second end, forms a tool engagement portion. This tool engagement portion serves to mount and dismount the cutting insert on the carrier. The tool engagement portion is preferably designed such that an associated tool engages from the end face of the cutting insert and is positioned or attached, in particular, along the rotational axis.

[0035] Further preferably, the tool engagement point is formed by at least two spatially separated projections or protrusions at the second end. A corresponding projection or protrusion is preferably formed by a recess. Depending on the application, one or both of the at least two projections are formed in a radial outer region on the front side of the second end. It is further expedient if one of the projections adjoins each of the two aforementioned primary flanks and in particular if each of the two projections is arranged in a transition region between a primary flank and the trailing secondary flute notch. Description of the characters

[0036] Embodiments of the invention are explained in more detail below with reference to a schematic drawing. In the drawing: Fig. 1 shows a perspective view of a modular rotary tool with a carrier and a cutting insert according to the prior art, Fig. 2 shows a top view of a cutting insert according to the invention, Fig. 3 in a perspective view of the cutting insert according to the invention, Fig. 4 in a first side view of the cutting insert according to the invention and Fig. 5 in a second side view of the cutting insert according to the invention.

[0037] Corresponding parts are provided with the same reference numerals in all figures. Description of the embodiment

[0038] A rotary tool 2, 4 described below as an example is designed as a modular rotary tool 2, 4 and has a base body or carrier 2 and a cutting insert 4 reversibly and detachably attached thereto. In the exemplary embodiment, the rotary tool 2, 4 is further designed as a drilling tool or drill for short, i.e., as a modular drill.

[0039] Fig. 1 shows a modular drill. This comprises the carrier 2 and a cutting insert 6 according to the prior art. To form the reversibly detachable connection between the carrier 2 and the cutting insert 6, a coupling receptacle 8 is formed on the carrier 2, which in the embodiment according to Fig. 1 has two opposing clamping bars 10.

[0040] The Fig. 2 to Fig. The cutting insert 4 shown in Figure 5 has a first end 12 and a second end 14 and forms with the first end 12 a coupling compatible with the coupling receptacle 8 of the carrier 2. In the exemplary embodiment, this has a coupling pin 13 and a guide pin 15, as for example in Fig. 5. As a result, the cutting insert 4 can also be reversibly and detachably mounted on the carrier 2 instead of the cutting insert 6, and in the mounted state, the carrier 2 and the cutting insert 4 form the rotary tool 2,4.

[0041] In contrast to the classic cutting insert 6, the cutting insert 4 has not only two, but four main cutting edges 16,18, namely two primary main cutting edges 16 and two secondary main cutting edges 18. This is particularly Fig. 2, as this shows a plan view of a front side 20 of the second end 14 of the cutting insert 4. The two primary main cutting edges 16 are connected to each other via a cross cutting edge 22 and are comparable to the main cutting edges of the classic cutting insert 6.

[0042] The additional secondary main cutting edges 18 of the cutting insert 4 are shorter than the primary main cutting edges 16. A secondary main cutting edge 18 is then assigned to each primary main cutting edge 16. This means that the main cutting edges 16, 18 are arranged around a rotation axis 24, with the primary main cutting edges 16 and the secondary main cutting edges 18 alternating.

[0043] Furthermore, the cutting insert 4 and also the entire modular rotary tool 2, 4 are designed rotationally symmetrically in the exemplary embodiment in such a way that when rotated around the rotation axis by 180°, they are essentially congruent.

[0044] In addition, the cutting insert 4 and the entire modular rotary tool 2, 4 are designed for a direction of rotation 26, as is usual for drilling tools. Therefore, the term "following" refers to a position sequence that results when viewed opposite to the specified direction of rotation 26. For the sake of clarity, the direction of rotation 26 is only shown in Fig. 2 is shown.

[0045] Furthermore, each main cutting edge 16, 18 is assigned a chip groove 28, 30. This means that each main cutting edge 16, 18 is followed by a corresponding chip groove 28, 30. Each primary main cutting edge 16 is assigned a primary chip groove 28, and each secondary main cutting edge 18 is assigned a secondary chip groove 30. The primary chip grooves 28 and the secondary chip grooves 30 have different widths. Each primary chip groove 28 has a primary width B, and each secondary chip groove 30 has a width b. The width B typically has a value that lies in the range 1.2 B to 3.0 B, and in particular in the range 1.5 B to 2.5 B.

[0046] In addition, the primary chip flutes 28 and the secondary chip flutes 30 have different rake angles. Each primary chip flute 28 defines a primary rake angle α, and each secondary chip flute 30 defines a secondary rake angle β. The two rake angles α, β are further selected such that each secondary chip flute 28 flows into the primary chip flute 30 of the trailing primary main cutting edge 16. In this way, the number of chip flutes 28, 30 is reduced from the end face 20 of the cutting insert 4 toward the coupling, and is thereby halved.

[0047] The carrier 2, in turn, has two carrier chip grooves 32. Once the cutting insert 2 is mounted on the carrier 2, each of the two primary chip grooves 28 transitions into one of the carrier chip grooves 32. The carrier chip grooves 32 and the primary chip groove 28 have identical or substantially identical chip angles α, γ, at least at the transition, and in particular also substantially identical cross-sections. For the secondary chip groove 30, however, no continuations are formed on the carrier 2.

[0048] Depending on the application, the primary rake angle α and the secondary rake angle β are further specified such that the ratio β / α has a value in the range of 1.5 to 3.0. Furthermore, the value is preferably in the range of 1.8 to 2.7.

[0049] Independently of this, depending on the application, a primary rake angle α with a value in the range of 15° to 45° is specified. More preferably, the value is in the range of 20° to 40°. In the exemplary embodiment, the value is approximately 30°.

[0050] For the secondary rake angle β, a value is advantageously specified that lies in the range between 45° and 70°. More preferably, the value lies in the range between 50° and 70°. In the exemplary embodiment, the value is approximately 60°.

[0051] As already explained above, the additional secondary main cutting edges 18 of the cutting insert 4 are shorter than the primary main cutting edges 16. Each secondary main cutting edge 18 extends in the radial direction 33 only over an outer radial region, specifically from a radially outer end 34 to a radially inner end 36. The distance A between the radially inner end 36 and the rotation axis 24, based on the diameter D of the rotary tool 2, 4, preferably has a value in the range 0.1 D to 0.4 D. Furthermore, the value of the distance is preferably in the range 0.2 D to 0.3 D.

[0052] Furthermore, each of the secondary main cutting edges 18 is shortened by a recess 38. Each of these two recesses 38, at least when viewed from the front side 20 of the cutting insert 4, forms a connection between a secondary chip groove 30 and the primary chip groove 28 of the trailing primary main cutting edge 16, with the connection being designed in the manner of a groove. A cooling channel 40 also opens into each of these two connections, with the cutting insert 4 forming exactly two cooling channels 40 in the exemplary embodiment.

[0053] As can be seen from the illustrations according to Fig. 2 to Fig. 5, each primary main cutting edge 16 is followed by a primary flank 42, i.e. a front-side primary flank 42. Each primary flank 42 runs at least partially into the trailing secondary chip groove 30.

[0054] Each secondary main cutting edge 18 is in turn followed by a secondary flank 44, i.e., a front-side secondary flank 44. Each secondary flank 44 runs into the trailing primary chip flute 28. In the exemplary embodiment, the secondary flanks 44 have a good approximation of a trapezoidal shape.

[0055] In the exemplary embodiment, the cutting insert 4 also has a tool engagement point at the second end 14. This tool engagement point serves for mounting and dismounting the cutting insert 4 on the carrier 2. The tool engagement point is designed such that an associated tool engages the end face 20 of the cutting insert 4 and is placed or attached in particular along the rotation axis 24. As can be seen from Fig.As can be seen in Figure 2, the tool engagement area is formed by two spatially separated recesses 46. The recesses 46 are formed in a radial outer region on the front side of the second end 14. Each of the two aforementioned primary flanks 42 is adjoined by one of the recesses 46. Furthermore, each of the two recesses 46 is arranged in a transition region between a primary flank 42 and the trailing secondary flute notch (30).

Claims

[1] Cutting insert (4) for a modular rotary tool (2, 4) which extends along a rotation axis (24) from a first end (12) to a second end (14), wherein - the first end (12) is a coupling designed for reversible connection to a carrier (2), - the second end (14) has an end face (20) on which a plurality of main cutting edges (16, 18) are formed, namely at least one primary main cutting edge (16) and at least one secondary main cutting edge (18) and - a primary chip groove (28) is assigned to the primary main cutting edge (16) and a secondary chip groove (30) is assigned to the secondary main cutting edge (18), characterized by that the primary chip groove (28) and the secondary chip groove (30) have different rake angles (α,β) and that the secondary chip groove (30) opens into the primary chip groove (28). [2] Cutting insert (4) according to claim 1, characterized bythat the primary chip groove (28) has a primary rake angle (α) and the secondary chip groove (30) has a secondary rake angle (β) and that the ratio of secondary rake angle (β) to primary rake angle (α) is in the range from 1.5 to 3.

0. [3] Cutting insert (4) according to claim 1 or 2, characterized by that the primary chip flute (28) has a primary rake angle (α) and that the value of the primary rake angle (α) is in the range of 15° to 45°. [4] Cutting insert (4) according to one of claims 1 to 3, characterized by that the secondary chip flute (30) has a secondary rake angle (β) and that the value of the secondary rake angle (β) is in the range between 45° and 75°. [5] Cutting insert (4) according to one of claims 1 to 4, characterized by that the secondary main cutting edge (18) is shorter than the primary main cutting edge (16). [6] Cutting insert (4) according to one of claims 1 to 4, characterized bythat the secondary main cutting edge (18) has an outer end (34) and an inner end (36) as seen in the radial direction (33), and that the distance (A) between the inner end (36) and the rotation axis (24) has a value in the range 0.1 D to 0.4 D with respect to a cutting insert diameter D. [7] Cutting insert (4) according to claim 5 or 6, characterized by that the secondary main cutting edge (18) is shorter than the primary main cutting edge (16) by means of a clearance (38). [8] Cutting insert (4) according to claim 7, characterized by that it has a cooling channel (40) which opens into the clearance (38). [9] Cutting insert (4) according to one of claims 1 to 8, characterized by that two primary main cutting edges (16) are formed, which are connected to one another in particular via a transverse cutting edge (22). [10] Cutting insert (4) according to claim 9, characterized bythat two secondary main cutting edges (16) are formed, each primary main cutting edge (16) being assigned a trailing secondary main cutting edge (18). [11] Cutting insert (4) according to claim 10, characterized by that each primary main cutting edge (16) is assigned a primary chip groove (28) and each secondary main cutting edge (18) is assigned a secondary chip groove (30), wherein each secondary chip groove (30) opens into the primary chip groove (28) of the trailing primary main cutting edge (16). [12] Cutting insert (4) according to claim 10 or 11, characterized by that each secondary main cutting edge (18) is shorter than the primary main cutting edges (16), that each secondary main cutting edge (18) is shorter by means of a clearance (38) and that each of these clearances (38) forms a front-side connection between a secondary chip groove (30) and the primary chip groove (28) of the trailing primary main cutting edge (16). [13] Cutting insert (4) according to one of claims 9 to 12, characterized by that a primary flank (42) adjoins each of the two primary main cutting edges (16), that the second end (14) forms a tool engagement with at least two protrusions (46), and that one of the protrusions (46) adjoins each of the two primary flanks (42). [14] Modular rotary tool (2,4) comprising a carrier (2) and a cutting insert (4) attached to the carrier, characterized by that the cutting insert (4) is designed as a cutting insert (4) according to one of the preceding claims. [15] Modular rotary tool (2,4) according to claim 11, characterized by that the carrier (2) has a carrier chip groove (32) for each primary chip groove (28) of the cutting insert (4) and that each of the primary chip grooves (28) is aligned with one of the carrier chip grooves (32).

Images