Cutting tool

Abstract

The invention relates to a cutting tool (1) having a blade seat (4) and a cutting blade (7) which is detachably mounted in the blade seat (4). A clamping element (13) is used to fix the cutting blade in the blade seat (4) by exerting a force in the centre of the cutting blade, which force has a first force component directed towards a bottom surface (5) of the blade seat and a second force component (L2) perpendicular to the bottom surface. The bottom surface of the blade seat (4) is provided with three protrusions (15a-15c) which form three exact contact points for a bottom surface (9) of the cutting blade (7). A first protrusion (15a) is positioned close to an active cutting edge (11), a second protrusion (15b) is positioned close to the second force component, and a third protrusion (15c) is positioned such that the protrusions together form a triangular shape.

Description

Technical Field

[0001] The present invention relates to a cutting tool according to the preamble of claim 1.

[0002] Therefore, the present invention relates to a cutting tool having one or more replaceable cutting inserts, each cutting insert being detachably mounted in an insert holder within the tool body of the cutting tool by means of a clamping element. Such a cutting tool may also be, for example, a turning tool or a drilling tool, but milling tools will be described as typical examples and the invention is not limited thereto.

[0003] The cutting tool of the present invention is typically attached to a computer numerical control (CNC) machine tool via the rear shank end of the tool body and operated by said machine tool to cut chips from the workpiece via at least one active cutting edge of at least one cutting portion positioned at the front cutting end of the tool body. Background Technology

[0004] This type of cutting tool has many advantages over cutting tools with a solid tool body (i.e., a cutting edge formed integral with the tool body). Several examples include: increased tool life due to less wear on the tool body itself, but primarily wear of the insert (which is then replaced with a new insert); reduced lead time during cutting operations, as poorly worn cutting edges can be quickly replaced instead of being reground; and increased versatility through the possibility of providing different types of cutting inserts suitable for different machining operations to the same tool body.

[0005] While this type of cutting tool offers certain advantages, it also presents a set of challenges, primarily due to its complex structure with a higher number of individual parts compared to solid cutting tools. For these tools to perform optimally, it is essential to precisely position and stabilize the cutting insert throughout the entire cutting or machining operation.

[0006] The characteristics of the cutting tool should be maintained as much as possible during cutting operations. This includes maintaining its characteristics under various conditions, such as exposure to cutting forces, vibrations, and other operating stresses. Furthermore, the tool should maintain high performance even after some degree of wear on both the insert and the tool body.

[0007] One of the key aspects to consider is reducing wear on the various components of the cutting tool. By minimizing wear, tool performance can be enhanced and its lifespan extended. These are just a few of the many aspects that affect the performance of this type of cutting tool.

[0008] Many of these challenges are associated with and influenced by the interface between the cutting insert and the insert holder of the tool body. A wide variety of interfaces exist between the cutting insert and insert holder in this type of cutting tool known and currently on the market, each with a different impact on the aforementioned challenges. Examples include: interlocking interfaces (US9682433, US8313270, US7819610, US7637701); planar surfaces at various angles (US8596933); and distance elements on the cutting insert (US8753045, US6126366) and / or distance elements on the tool body (US8568065, US7429150).

[0009] There are ongoing efforts to improve the arrangement of cutting inserts in the insert holder of this type of cutting tool. This includes considering the parameters or aspects mentioned above, and finding ways to optimize them for better performance. Summary of the Invention

[0010] The object of the present invention is to provide a cutting tool of the type defined in the introduction, which is improved in at least one aspect compared with such cutting tools already known, particularly providing improved fixation and stability of the at least one cutting insert in the insert holder, thereby reducing undesirable movement of the cutting insert relative to the tool body during cutting operations, which in turn leads to increased performance and reduced wear during the use of the cutting tool.

[0011] According to the present invention, this objective is achieved by providing a cutting tool in which the first support surface of the insert holder is provided with at least three protrusions forming a first contact point, a second contact point, and a third contact point at the first support surface for the bottom surface of the cutting insert. The at least three protrusions are positioned on the first support surface of the blade holder such that, in a top view perpendicular to the first support surface, The first protrusion is positioned between the center of the recess and the edge support point, wherein the distance from the center of the first protrusion to the center of the recess is greater than the distance from the center of the first protrusion to the edge support point. The second protrusion is positioned between the center of the recess and the second support surface of the blade holder, wherein the angle formed between a first imaginary line from the center of the recess to the center of the second protrusion and a second imaginary line from the center of the recess in the direction of the second force component is 20 degrees or less. The third protrusion is positioned such that an imaginary straight line connecting the centers of the first, second, and third protrusions forms a first triangular shape that encloses the center of the recess.

[0012] Three protrusions provide multiple strategically positioned contact points on the bottom surface of the cutting insert, thereby enhancing the stability of the insert within the insert holder. In particular, the protrusions are positioned to reduce undesirable movement of the cutting insert relative to the tool body during cutting operations with the cutting tool. This results in increased performance and reduced wear during the use of the cutting tool.

[0013] Moreover, the specific arrangement of the protrusions allows for optimized force distribution in the cutting insert and insert holder during cutting operations, which improves cutting efficiency and further reduces wear on both the insert and the tool body.

[0014] According to an embodiment of the present invention, the recess of the cutting blade is disposed at the center of the top surface of the cutting blade.

[0015] According to another embodiment of the invention, the recess of the cutting blade is in the form of a through hole extending from an inlet in the top surface of the cutting blade to an outlet in the bottom surface of the cutting blade, the first support surface of the blade holder is provided with a central hole, and the clamping element is a threaded fastener.

[0016] According to another embodiment of the invention, in the top view of the first support surface of the blade holder perpendicular to the blade holder, an imaginary straight line extending through the center of the recess in the longitudinal extension direction of the blade body and an imaginary straight line extending through the center of the recess perpendicular to the direction together divide the first support surface of the blade holder into four quadrants, wherein the first quadrant is the quadrant in which the second force component extends, and the second quadrant, the third quadrant, and the fourth quadrant follow the first quadrant in a clockwise direction, wherein the center of the first protrusion is located in the third quadrant, the center of the second protrusion is located in the first quadrant, and the center of the third protrusion is located in the second quadrant.

[0017] According to another embodiment of the present invention, in the top view of the first support surface directly facing the blade holder, an imaginary straight line connecting the center of the second protrusion, the center of the third protrusion, and the center of the recess forms a second triangular shape; an imaginary straight line connecting the center of the third protrusion, the center of the first protrusion, and the center of the recess forms a third triangular shape; and an imaginary straight line connecting the center of the first protrusion, the center of the second protrusion, and the center of the recess forms a fourth triangular shape, wherein the second triangular shape, the third triangular shape, and the fourth triangular shape together constitute the first triangular shape, and wherein the surface area of ​​the triangular shape with the largest surface area among the second triangular shape, the third triangular shape, and the fourth triangular shape is less than 30%, preferably less than 20%, and more preferably less than 10% larger than the surface area of ​​the triangular shape with the smallest surface area among the second triangular shape, the third triangular shape, and the fourth triangular shape.

[0018] According to another embodiment of the invention, in the top view of the first support surface perpendicular to the blade holder, the distance from the center of the first protrusion to the center of the recess is at least twice the distance from the center of the first protrusion to the edge support point, preferably at least 2.5 times, more preferably at least 3 times, and even more preferably at least 3.5 times.

[0019] According to another embodiment of the invention, in the top view of the first support surface directly facing the blade holder, the angle formed between the first imaginary line and the second imaginary line is 15 degrees or less, more preferably 10 degrees or less.

[0020] According to another embodiment of the invention, in the top view of the first support surface directly facing the blade holder, the second imaginary straight line intersects the second protrusion.

[0021] According to another embodiment of the invention, the second support surface is arranged to extend away from the first support surface at a first peripheral side of the first support surface in a second plane, the second plane forming an angle of 70-110 degrees with the first plane in which the first support surface extends.

[0022] According to another embodiment of the present invention, the second support surface is provided with a fourth protrusion, the fourth protrusion forming a first contact point for the outer peripheral surface of the cutting blade at the second support surface, thereby forming a fourth contact point for the cutting blade in the blade holder.

[0023] According to another embodiment of the invention, in a side view of the blade holder along the first support surface and toward the second support surface, the second support surface has: a front end and an opposite rear end as seen in the longitudinal extension direction of the blade body; and a bottom end and an opposite top end, the second support surface being connected to the first support surface via the bottom end, the top end being positioned furthest from the first support surface, wherein the fourth protrusion is arranged such that the distance from the center of the fourth protrusion to the bottom end of the second support surface is greater than the distance from the center of the fourth protrusion to the top end of the second support surface, and the distance from the center of the fourth protrusion to the rear end of the second support surface is greater than the distance from the center of the fourth protrusion to the front end of the second support surface.

[0024] According to another embodiment of the invention, the blade holder further has a third support surface extending in a third plane, the third plane forming an angle with each of the first plane and the second plane, wherein the third support surface is arranged to extend away from the first support surface at a second outer peripheral side of the first support surface in the third plane, the third plane forming an angle of 70-110 degrees with the first plane in which the first support surface extends, and wherein the third support surface is provided with a fifth protrusion forming a first contact point for the outer peripheral surface of the cutting blade at the third support surface, thereby forming a fifth contact point for the cutting blade in the blade holder.

[0025] According to another embodiment of the invention, in a front view of the blade holder along the first support surface and directly facing the third support surface, the third support surface has an inner end and an opposite outer end, as well as a bottom end and an opposite top end. The third support surface is connected to the rear end of the second support surface via the inner end, the outer end is positioned closer to the outer peripheral surface of the tool body than the inner end, the third support surface is connected to the first support surface via the bottom end, and the top end is positioned furthest from the first support surface. The fifth protrusion is arranged such that the distance from the center of the fifth protrusion to the top end of the third support surface is greater than the distance from the center of the fifth protrusion to the bottom end of the third support surface, and the distance from the center of the fifth protrusion to the outer end of the third support surface is greater than the distance from the center of the fifth protrusion to the inner end of the third support surface.

[0026] According to another embodiment of the invention, the second support surface is further provided with a sixth protrusion, the sixth protrusion forming a second contact point on the outer peripheral surface of the cutting blade at the second support surface, wherein the sixth protrusion is arranged such that, when viewed in the length direction from the front end of the second support surface toward the rear end, the center of the sixth protrusion is located between the center of the fourth protrusion and the rear end of the second support surface, and when viewed in the height direction from the bottom end of the second support surface toward the top end, the center of the sixth protrusion is located between the center of the fourth protrusion and the top end of the second support surface, and wherein, in the top view of the first support surface directly facing the blade holder, the second imaginary straight line intersects the sixth protrusion.

[0027] According to another embodiment of the invention, each of the protrusions is formed with a convex contact surface, thereby being configured to provide a precise contact point with the associated surface of the cutting blade that contacts the convex contact surface.

[0028] According to another embodiment of the invention, the clamping element is a clamping screw.

[0029] According to another embodiment of the invention, the fourth protrusion is arranged such that the distance from the center of the fourth protrusion to the bottom end of the second support surface is at least 1.2 times greater than the distance from the center of the fourth protrusion to the top end of the second support surface, preferably at least 1.3 times greater, and the distance from the center of the fourth protrusion to the rear end of the second support surface is at least 3 times greater than the distance from the center of the fourth protrusion to the front end of the second support surface, preferably at least 4 times greater, more preferably at least 5 times greater, and most preferably at least 6 times greater.

[0030] According to another embodiment of the invention, the fifth protrusion is arranged such that the distance from the center of the fifth protrusion to the top of the third support surface is at least 3 times greater than the distance from the center of the fifth protrusion to the bottom of the third support surface, preferably at least 4 times greater, more preferably at least 5 times greater, and most preferably at least 6 times greater, and the distance from the center of the fifth protrusion to the outer end of the third support surface is at least 3 times greater than the distance from the center of the fifth protrusion to the inner end of the third support surface, preferably at least 4 times greater, more preferably at least 5 times greater, and most preferably at least 6 times greater.

[0031] According to another embodiment of the invention, the cutting insert further has a corner portion, wherein a corner cutting edge portion is provided at the transition portion between the outer peripheral surface and the top surface of the cutting insert, wherein the corner cutting edge portion interconnects the main cutting edge portion and the auxiliary cutting edge portion such that they together form a functional cutting edge.

[0032] According to another embodiment of the invention, the cutting tool is a milling tool, especially a square shoulder milling tool.

[0033] According to another embodiment of the invention, each of the first protrusion, the second protrusion, and the third protrusion has a convex shape in order to provide a precise contact point against the bottom surface of the cutting blade.

[0034] According to another embodiment of the invention, each of the first protrusion, the second protrusion, and the third protrusion has a semi-elliptical or hemispherical shape.

[0035] According to another embodiment of the invention, each of the protrusions has a semi-elliptical or hemispherical shape.

[0036] According to another embodiment of the invention, when viewed in the top view perpendicular to the first support surface of the blade holder, the surface area of ​​each of the first protrusion, the second protrusion, and the third protrusion is smaller than the cross-sectional area of ​​the central hole in the first support surface.

[0037] Further advantages and advantageous features of the present invention will become apparent from the following detailed description of embodiments of the invention. Attached Figure Description

[0038] Referring to the accompanying drawings, the following is a detailed description of embodiments of the present invention cited by way of example.

[0039] In the attached diagram: Figure 1 This is an exploded perspective view taken from the tip of a cutting tool according to an embodiment of the present invention, which is in the form of a milling cutter, viewed at an angle. Figure 2 yes Figure 1 A top view detail of the cutting part of a cutting tool, wherein the cutting insert is detachably mounted in a fixed position in the insert holder of the cutting part in the tool body; Figure 3 Is with Figure 2 The corresponding view shows the blade holder of the cutting section (without the cutting blade and clamping elements). Figure 4 This is a perspective view taken at an angle from the front end of the cutting tool, showing... Figure 2-3The blade holder (without cutting blades and clamping elements); Figure 5 yes Figure 4 A detailed side elevation view of the blade holder in the direction toward the second support surface of the blade holder; and Figure 6 From Figure 4 A slightly perspective view of the front end of the blade holder, viewed in the direction of the third support surface of the blade holder. Detailed Implementation

[0040] The cutting tool 1 according to an embodiment of the present invention is in Figure 1-6 As shown in the figures, and will now be described with reference to all of these figures in combination.

[0041] The cutting tool 1, which is a milling cutter (and more precisely a square-shoulder milling cutter), includes a tool body 2 having: a rear shank end 20 configured for attachment to a machine tool (such as a CNC machine tool); and an opposite front cutting end 21 provided with at least one cutting portion 3. The longitudinal extension length of the tool body 2 is measured from the rear shank end 20 to the front cutting end 21, and is defined at the illustrated tool location by a central longitudinal axis 30 that coincides with the axis of rotation of the milling cutter. Therefore, the axial direction of the tool body 2 and the cutting tool 1 is the same as their longitudinal direction.

[0042] In the illustrated embodiment, the tool body 2 is provided with two cutting portions, each having a insert holder for accommodating a corresponding cutting insert. Since these cutting portions have exactly the same construction, only one of these cutting portions is fully shown in the drawings and described in detail below, and its structural and functional description is also valid for the other cutting portion and for all cutting portions in the case of a cutting tool having more than two cutting portions. The number of cutting portions with insert holders and cutting inserts at the tool body of the cutting tool according to the invention is most commonly 1-12.

[0043] As already mentioned, the cutting portion 3 includes a blade holder 4 having a first support surface 5 and a second support surface 6. The first support surface 5 forms the bottom surface of the blade holder, extending in a first plane, and the second support surface 6 forms a first sidewall of the blade holder, extending in a second plane at an angle to the first plane. The blade holder 4 also has a third support surface 24 extending in a third plane at an angle to each of the first and second planes, and the third support surface 24 forms a second sidewall of the blade holder.

[0044] The second support surface 6 is arranged to extend away from the first support surface 5 in a second plane on the first outer peripheral side of the first support surface 5, the second plane forming an angle of 70-110 degrees with the first plane in which the first support surface 5 extends. The third support surface 24 is arranged to extend away from the first support surface 5 in a third plane on the second outer peripheral side of the first support surface 5, the third plane forming an angle of 70-110 degrees with the first plane in which the first support surface 5 extends. Therefore, the first support surface 5, the second support surface 6, and the third support surface 24 are arranged together to form the bag-shaped blade holder 4.

[0045] The cutting part 3 also includes a cutting insert 7 and a clamping element 13 in the form of a threaded fastener or clamping screw to securely fix the cutting insert in a fixed position in the insert holder 4. The cutting insert 7 has a top surface 8, an opposite bottom surface 9, and an outer peripheral surface 10 that extends between the top surface 8 and the bottom surface 9, thereby interconnecting the top and bottom surfaces around the outer periphery of the cutting insert.

[0046] The cutting insert 7 has a cutting edge 11, which includes: a main cutting edge portion 11a at the long side 33 of the cutting insert; an auxiliary cutting edge portion 11b at the short side 34 of the cutting insert; and a corner cutting edge portion 31 on the corner portion 32 of the cutting insert 7, which interconnects the main cutting edge portion and the auxiliary cutting edge portion, and the corner portion 32 forms a transition between the short side and the long side. These cutting edge portions 11a, 11b, and 31 are respectively formed at the transition between the top surface 8 and the outer peripheral surface 10 on the long side forming the first flank face, the short side forming the second flank face, and the corner portion. The cutting insert 7 is also provided with similar cutting edges in opposite directions along the diameter (so that the cutting insert can be indexed 180 degrees), that is, it is provided with two usable cutting edges.

[0047] The cutting insert 7 also has a recess 16 disposed at the center of its top surface 8. More specifically, the recess 16 is in the form of a through hole that extends from an inlet in the top surface 8 of the cutting insert 7 to an outlet in the bottom surface 9 of the cutting insert 7, that is, it passes straight through the cutting insert 7 from the top surface 8 to the bottom surface 9.

[0048] exist Figure 2The diagram illustrates how the cutting insert 7 is detachably mounted in a fixed position within the insert holder 4 during the use of the cutting tool 1 (i.e., during a cutting operation). In this position, the bottom surface 9 of the cutting insert 7 is arranged in contact with the first support surface 5 of the insert holder 4, the opposite top surface 8 of the cutting insert 7 serves as the rake face, and the cutting edge 11, formed by the main cutting edge portion 11a, the auxiliary cutting edge portion 11b, and the corner cutting edge portion 31, is arranged to constitute the functional cutting edge of the cutting tool 1 and has a functional cutting point 12, which is defined as the point where the imaginary extensions of the main cutting edge portion 11a and the auxiliary cutting edge portion 11b of the functional cutting edge 11 meet.

[0049] The cutting insert 7 is held in place in the insert holder by engaging the recess 16 in the top surface 8 of the cutting insert 7 with the clamping element 13 and by applying force to the cutting insert 7. The cutting insert 7 is releasably fixed in this fixed position in the insert holder 4. Further described, the clamping element 13 has: a front end that is securely fixed in a central hole 17 in the first surface 5 of the insert holder 4 by a threaded connection; a rear end having a head wider than the recess 16 that presses against the adjacent portion of the recess of the cutting insert 7; and a middle portion of the clamping element 13 that extends through the cutting insert 7 in the recess 16.

[0050] The force applied by the clamping element 13 includes a first force component in the direction from the top surface 8 of the cutting blade 7 toward the first support surface 5 of the blade holder 4, which pushes the bottom surface 9 of the cutting blade 7 against the first support surface 5 of the blade holder 4. The force also includes a second force component in the direction from the center of the recess 14 toward the second support surface 6 of the blade holder 4, as shown by imaginary line L2, thereby pressing a portion of the outer peripheral surface 10 of the cutting blade 7 against the second support surface 6.

[0051] The second force component is achieved by the offset arrangement of the center hole 17 of the first support surface 5 of the blade holder 4 and the recess 16 of the cutting blade 7, thereby inducing tension in the clamping element 13 by fixing the clamping element 13 in the center hole 17, thereby pushing the clamping element 13 and thus the cutting blade 7 toward the second support surface 6 of the blade holder 4.

[0052] The first support surface 5 of the blade holder 4 is provided with three protrusions 15a-15c. These protrusions form first, second, and third contact points on the first support surface 5 for cutting the bottom surface 9 of the blade 7. (A top view perpendicular to the first support surface 5 of the blade holder 4 is shown.) Figure 2In the first protrusion 15a, the first protrusion 15a is located between the center 14 of the recess of the cutting blade 7 and the edge support point, that is, between the center 14 of the recess and the point on the outer edge of the first support surface that is closest to the effective cutting point 12. The edge support point is defined as the point on the first support surface 5 that has the smallest distance from the effective cutting point 12 (usually called the Pk point).

[0053] The distance from the center of the first protrusion of the cutting insert 7 to the center of the recess 14 is more than 3.5 times greater than the distance from the center of the first protrusion to the edge support point. That is, the center of the first protrusion 15a or at least the center of its contact point is positioned approximately closer to the edge support point than to the center of the recess 14, thereby providing robust support for the cutting insert 7 by being close to the active cutting edge (where the cutting insert 7 is subjected to large forces).

[0054] In the same view, the second protrusion 15b is positioned between the recess center 14 of the cutting insert 7 and the second support surface 6 of the insert holder 4. The angle α1 formed between a first imaginary line L1 from the recess center 14 of the cutting insert 7 to the center of the second protrusion and an imaginary line L2 from the recess center 14 of the cutting insert 7 in the direction of the second force component is less than 10 degrees; that is, the center of the second protrusion 15b, or at least the center of its contact point, is located near the second force component. In the top view, the second protrusion 15b is further arranged such that the imaginary line L2 from the recess center 14 of the cutting insert 7 in the direction of the second force component intersects the second protrusion 15b, i.e., extends within its boundary line. Therefore, the second protrusion 15b is arranged to balance the second force component, thereby stabilizing the cutting insert 7 in a fixed position.

[0055] In this view, the third protrusion 15c is positioned such that the imaginary straight line L3-L5 connecting the centers of the first protrusion 15a, the second protrusion 15b, and the third protrusion 15c forms a first triangular shape that encloses the recessed center 14 of the cutting blade 7.

[0056] More specifically, the third protrusion 15c is positioned such that imaginary lines L4, L8, and L1 connecting the centers of the second and third protrusions and the center of the recess 14 together form a second triangular shape e; imaginary lines L5, L9, and L8 connecting the centers of the third and first protrusions and the center of the recess 14 together form a third triangular shape f; and imaginary lines L3, L1, and L9 connecting the centers of the first and second protrusions and the center of the recess 14 together form a fourth triangular shape g. The second triangular shape e, the third triangular shape f, and the fourth triangular shape g together constitute the first triangular shape and have similar surface areas; that is, the surface area of ​​the triangle with the largest surface area among the second, third, and fourth triangular shapes e, f, and g is less than 10% larger than the surface area of ​​the triangle with the smallest surface area among the second, third, and fourth triangular shapes g. This positioning of the three protrusions at the first support surface 5 has been shown to provide effective support for the cutting tool 7 during various cutting operations.

[0057] The first support surface 5 is further divided into four quadrants A and D in its top view. These quadrants are defined by imaginary lines L6 and L7. Imaginary line L6 extends parallel to the first plane in the longitudinal extension direction of the tool body 2 and passes through the recess center 14 of the cutting insert 7. Imaginary line L7 extends perpendicular to the first plane, parallel to the first plane, and passes through the recess center 14, thus intersecting with the first plane. The intersection point is located in the recess center 14. The first quadrant A is defined as the quadrant in which the second force component extends, and the second quadrant B, the third quadrant C, and the fourth quadrant D follow the first quadrant A in this order in a clockwise direction (see...). Figure 2 A first protrusion 15a, a second protrusion 15b, and a third protrusion 15c are also arranged at the first support surface 5, such that: the center of the first protrusion is located in the third quadrant C, the center of the second protrusion is located in the first quadrant A, and the center of the third protrusion is located in the second quadrant B.

[0058] For example, in the side view of the blade holder 4 along the first support surface 5 and towards the second support surface 6 ( Figure 5 As seen in the diagram, the second support surface 6 has a front end 18 and an opposite rear end 19, as seen in the longitudinal extension direction of the tool body 2. The second support surface 6 also has a bottom end 22 and an opposite top end 23, the bottom end 22 connecting the second support surface 6 to the first support surface 5 via a transition corner surface, and the top end 23 being positioned furthest from the first support surface 5.

[0059] The second support surface 6 is provided with a fourth protrusion 15d and a sixth protrusion 15f, thereby forming a first contact point and a second contact point for the outer peripheral surface 10 of the cutting blade 7 at the second support surface 6.

[0060] The fourth protrusion 15d is arranged such that the distance from the center of the fourth protrusion to the bottom end 22 of the second support surface 6 is more than 1.3 times the distance from the center of the fourth protrusion to the top end 23 of the second support surface 6, and such that the distance from the center of the fourth protrusion to the rear end 19 of the second support surface 6 is more than 6 times the distance from the center of the fourth protrusion to the front end 18 of the second support surface 6. Simply put, the fourth protrusion 15d is arranged in the top front corner of the second support surface 6, as seen in this side view.

[0061] The sixth protrusion 15f is arranged such that, when viewed along the length of the second support surface 6 from its front end 18 toward its rear end 19, the center of the sixth protrusion 15f is located between the center of the fourth protrusion and the rear end 19 of the second support surface 6, and when viewed along the height of the second support surface 6 from its bottom end 22 toward its top end 23, the center of the sixth protrusion 15f is located between the center of the fourth protrusion and the top end 23 of the second support surface 6. The sixth protrusion 15f is further arranged such that, in a top view perpendicular to the first support surface 5 facing the blade holder 4 (… Figure 2 In the figure, the imaginary straight line L2, starting from the center 14 of the recess of the cutting blade 7 and in the direction of the second force component, intersects the sixth protrusion 15f.

[0062] As seen in the front view of the blade holder 4 along the first support surface 5 and directly toward the third support surface 24 (as in... Figure 6 As can be seen visually, the third support surface 24 has: an inner end 25 connected to the rear end 19 of the second support surface 6 via a transition corner surface; and an opposite outer end 26 positioned closer to and more specifically at the outer peripheral surface 27 of the tool body 2. The third support surface 24 also has a bottom end 28 and an opposite top end 29, the bottom end 28 connecting the third support surface 24 to the first support surface 5 via a transition corner surface, and the top end 29 positioned furthest from the first support surface 5.

[0063] The third support surface 24 is provided with a fifth protrusion 15e, which forms a first contact point on the outer peripheral surface 10 of the cutting blade 7. The fifth protrusion 15e is arranged such that the distance from the center of the fifth protrusion to the top apex 29 of the third support surface 24 is more than six times the distance from the center of the fifth protrusion to the bottom apex 28 of the third support surface 24, and the distance from the center of the fifth protrusion to the outer apex 26 of the third support surface 24 is more than six times the distance from the center of the fifth protrusion to the inner apex 25 of the third support surface 24. Accordingly, the fifth protrusion 15e is positioned in the bottom inner corner of the third support surface, as seen in the front view.

[0064] Each of the six protrusions 15a-15f arranged in the insert holder 4 is formed with a convex contact surface provided by a protrusion having a semi-elliptical or hemispherical design. Each protrusion thus provides a small and precise contact point with the associated surfaces 9, 10 of the cutting insert 7 that contact the convex contact surface, and together they provide six strategically positioned contact points between the cutting insert 7 and the insert holder 4, thereby effectively locking the cutting insert in six degrees of freedom and minimizing the movement of the cutting insert during cutting operations.

[0065] The retention of cutting inserts in their associated insert holders is a fundamental part of the machining industry. Minimizing insert movement during machining operations is crucial for ensuring quality aspects such as durability, reliability, and repeatability. The innovative design of the cutting tool 1 according to the invention (in which semi-elliptical or hemispherical protrusions are strategically positioned in the insert holder 4) offers several advantages in this regard. A few examples include: uniform pressure distribution in different parts of the cutting portion 3 during cutting operations; reduced movement of the cutting insert 7 relative to the insert holder 4; and increased performance and lifespan of the cutting tool 1.

[0066] Essentially, the strategic positioning of the protrusions (and thus the contact points between the cutting insert and the insert holder) is key to these advantages, allowing these protrusions to absorb forces in any direction and ensure that contact between the cutting insert and the insert holder is always maintained.

[0067] Of course, the present invention is not limited in any way to the embodiments described above. Rather, many possibilities for modifications to the invention will be apparent to those skilled in the art without departing from the basic concept of the invention as defined in the appended claims.

[0068] The distance from a point, a line, or one end to another point, another line, or another end should be interpreted as the shortest possible distance between them. For example, the distance between a point and a apex should be measured from the point to a point located at the minimum distance from the point along the apex.

[0069] The term "center" as used to describe, for example, "center of the recess" or "center of the first protrusion," should be interpreted as referring to the center point of the recess or first protrusion as measured by observing the recess or first protrusion in a two-dimensional view seen from above.

[0070] When a statement claims that a surface extends in a plane, it does not necessarily imply that the surface is perfectly flat, or that every part of the surface exists within the same plane. Rather, the phrase primarily refers to the dominant extension of the surface.

Claims

1. A cutting tool (1) comprising a tool body (2) having at least one cutting portion (3), the at least one cutting portion (3) comprising: - Blade holder (4), the blade holder (4) having a first support surface (5) and a second support surface (6), the first support surface (5) extending in a first plane, and the second support surface (6) extending in a second plane forming an angle with the first plane; - A cutting insert (7) having a top surface (8), an opposite bottom surface (9), an outer peripheral surface (10), and at least one cutting edge (11), the outer peripheral surface (10) extending between the top surface (8) and the bottom surface (9), the at least one cutting edge (11) comprising a main cutting edge portion (11a) and an auxiliary cutting edge portion (11b) formed at a transition between the top surface (8) and the outer peripheral surface (10), the cutting insert (7) further having a recess (16) disposed in the top surface (8) of the cutting insert (7); and - Clamping element (13), wherein The cutting insert (7) is detachably mounted in a fixed position within the insert holder (4), in which the bottom surface (9) of the cutting insert (7) is arranged in contact with the first support surface (5) of the insert holder (4), the opposite top surface (8) of the cutting insert (7) serves as the rake face, and the at least one cutting edge (11) is arranged to form an effective cutting edge of the cutting tool (1) and has an effective cutting point (12), the effective cutting point (12) being defined as the point where the imaginary extensions of the main portion (11a) and the auxiliary portion (11b) of the effective cutting edge (11) meet. The first support surface (5) has an edge support point, which is defined as a point on the first support surface (5) that has the minimum distance from the active cutting point (12). The clamping element (13) is arranged and configured to releasably secure the cutting blade (7) in the fixed position in the blade holder (4) by engaging the recess (16) in the top surface (8) of the cutting blade (7) and by applying force to the cutting blade (7), the force including a first force component in a direction from the top surface (8) of the cutting blade (7) toward the first support surface (5) of the blade holder (4) and a second force component in a direction from the center (14) of the recess toward the second support surface (6) of the blade holder (4). The tool holder (4) is characterized in that its first support surface (5) is provided with at least three protrusions (15a-15c), which form a first contact point, a second contact point and a third contact point on the first support surface (5) for the bottom surface (9) of the cutting tool (7). The at least three protrusions (15a-15c) are positioned on the first support surface (5) of the blade holder (4) such that, in a top view perpendicular to the first support surface (5), The first protrusion (15a) is positioned between the center of the recess (14) and the edge support point, wherein the distance from the center of the first protrusion to the center of the recess (14) is greater than the distance from the center of the first protrusion to the edge support point. The second protrusion (15b) is positioned between the center of the recess (14) and the second support surface (6) of the blade holder (4), wherein the angle (α1) formed between a first imaginary straight line (L1) from the center of the recess (14) to the center of the second protrusion and a second imaginary straight line (L2) from the center of the recess (14) in the direction of the second force component is 20 degrees or less, and The third protrusion (15c) is positioned such that an imaginary straight line (L3-L5) connecting the centers of the first protrusion, the second protrusion, and the third protrusion forms a first triangular shape that encloses the center of the recess (14).

2. The cutting tool (1) according to claim 1, characterized in that, The recess (16) of the cutting blade (7) is arranged at the center of the top surface (8) of the cutting blade (7).

3. The cutting tool (1) according to claim 2, characterized in that: The recess (16) of the cutting blade (7) is in the form of a through hole, which extends from an inlet in the top surface (8) of the cutting blade (7) to an outlet in the bottom surface (9) of the cutting blade (7); the first support surface (5) of the blade holder (4) is provided with a central hole (17); and the clamping element (13) is a threaded fastener.

4. The cutting tool (1) according to claim 2 or 3, characterized in that, In the top view of the first support surface (5) of the blade holder (4) perpendicular to the blade body (2), an imaginary straight line (L6) extending through the center of the recess (14) in the longitudinal extension direction of the blade body (2) and an imaginary straight line (L7) extending through the center of the recess (14) perpendicular to the direction divide the first support surface (5) of the blade holder (4) into four quadrants (AD), wherein the first quadrant (A) is the quadrant in which the second force component extends, and the second quadrant (B), the third quadrant (C) and the fourth quadrant (D) follow the first quadrant (A) in a clockwise direction, wherein the center of the first protrusion is located in the third quadrant (C), the center of the second protrusion is located in the first quadrant (A), and the center of the third protrusion is located in the second quadrant (B).

5. The cutting tool (1) according to any one of claims 2-4, characterized in that, In the top view of the first support surface (5) directly facing the blade holder (4), imaginary straight lines (L4, L8, L1) connecting the center of the second protrusion, the center of the third protrusion, and the center of the recess (14) together form a second triangle shape (e); imaginary straight lines (L5, L9, L8) connecting the center of the third protrusion, the center of the first protrusion, and the center of the recess (14) together form a third triangle shape (f); and imaginary straight lines (L3, L1, L9) connecting the center of the first protrusion, the center of the second protrusion, and the center of the recess (14) together form a fourth triangle shape. The first triangle shape is defined as follows: wherein the second triangle shape (e), the third triangle shape (f), and the fourth triangle shape (g) together constitute the first triangle shape, and wherein the surface area of ​​the triangle shape with the largest surface area among the second triangle shape (e), the third triangle shape (f), and the fourth triangle shape (g) is less than 30%, preferably less than 20%, and more preferably less than 10% larger than the surface area of ​​the triangle shape with the smallest surface area among the second triangle shape (e), the third triangle shape (f), and the fourth triangle shape (g).

6. The cutting tool (1) according to any one of the preceding claims, characterized in that, In the top view of the first support surface (5) directly facing the blade holder (4), the distance from the center of the first protrusion to the center of the recess (14) is at least twice the distance from the center of the first protrusion to the edge support point, preferably at least 2.5 times, more preferably at least 3 times, and even more preferably at least 3.5 times.

7. The cutting tool (1) according to any one of the preceding claims, characterized in that, In the top view of the first support surface (5) directly facing the blade holder (4), the angle (α1) formed between the first imaginary straight line (L1) and the imaginary straight line (L2) in the direction of the second force component from the center of the recess (14) is 15 degrees or less, more preferably 10 degrees or less.

8. The cutting tool (1) according to any one of the preceding claims, characterized in that, In the top view of the first support surface (5) directly facing the blade holder (4), the imaginary straight line (L2) in the direction of the second force component, starting from the center (14) of the recess, intersects the second protrusion (15b).

9. The cutting tool (1) according to any one of the preceding claims, characterized in that, The second support surface (6) is arranged to extend away from the first support surface (5) at a first outer peripheral side of the first support surface (5) in a second plane, the second plane forming an angle of 70-110 degrees with the first plane in which the first support surface (5) extends.

10. The cutting tool (1) according to any one of the preceding claims, characterized in that, The second support surface (6) is provided with a fourth protrusion (15d), which forms a first contact point on the outer peripheral surface (10) of the cutting blade (7) at the second support surface (6), thereby forming a fourth contact point for the cutting blade (7) in the blade holder (4).

11. The cutting tool (1) according to claim 10, characterized in that, In a side view of the blade holder (4) along the first support surface (5) and toward the second support surface (6), the second support surface (6) has: a front end (18) and an opposite rear end (19) as seen in the longitudinal extension direction of the blade body (2); and a bottom end (22) and an opposite top end (23), the second support surface (6) being connected to the first support surface (5) via the bottom end (22), the top end (23) being positioned furthest from the first support surface (5), wherein the fourth protrusion (15d) is arranged such that the distance from the center of the fourth protrusion to the bottom end (22) of the second support surface (6) is greater than the distance from the center of the fourth protrusion to the top end (23) of the second support surface (6), and the distance from the center of the fourth protrusion to the rear end (19) of the second support surface (6) is greater than the distance from the center of the fourth protrusion to the front end (18) of the second support surface (6).

12. The cutting tool (1) according to claim 9 in conjunction with claim 10 or 11, characterized in that, The blade holder (4) also has a third support surface (24) extending in a third plane, the third plane forming an angle with each of the first plane and the second plane, wherein the third support surface (24) is arranged to extend away from the first support surface (5) at a second outer peripheral side of the first support surface (5) in the third plane, the third plane forming an angle of 70-110 degrees with the first plane in which the first support surface (5) extends, and wherein the third support surface (24) is provided with a fifth protrusion (15e), the fifth protrusion (15e) forming a first contact point for the outer peripheral surface (10) of the cutting blade (7) at the third support surface (24), thereby forming a fifth contact point for the cutting blade (7) in the blade holder (4).

13. The cutting tool (1) according to claim 12, characterized in that, In a front view of the blade holder (4) along the first support surface (5) and directly toward the third support surface (24), the third support surface (24) has an inner end (25) and an opposite outer end (26), as well as a bottom end (28) and an opposite top end (29). The third support surface (24) is connected to the rear end (19) of the second support surface (6) via the inner end (25). The outer end (26) is positioned closer to the outer peripheral surface (27) of the tool body (2) than the inner end (25). The third support surface (24) is connected to the rear end (19) of the second support surface (6) via the bottom end (28). The fifth protrusion (15e) is connected to the first support surface (5), the top end (29) being positioned furthest from the first support surface (5), wherein the fifth protrusion (15e) is arranged such that the distance from the center of the fifth protrusion to the top end (29) of the third support surface (24) is greater than the distance from the center of the fifth protrusion to the bottom end (28) of the third support surface (24), and the distance from the center of the fifth protrusion to the outer end (26) of the third support surface (24) is greater than the distance from the center of the fifth protrusion to the inner end (25) of the third support surface (24).

14. The cutting tool (1) according to any one of claims 10-13, characterized in that, The second support surface (6) is further provided with a sixth protrusion (15f), which forms a second contact point on the second support surface (6) for the outer peripheral surface (10) of the cutting blade (7). The sixth protrusion (15f) is arranged such that, when viewed along the length of the second support surface (6) from the front end (18) toward the rear end (19), the center of the sixth protrusion (15f) is located between the center of the fourth protrusion and the rear end (19) of the second support surface (6). Between the fourth protrusion and the top end (23) of the second support surface (6), and when viewed in the height direction from the bottom end (22) of the second support surface (6) toward the top end (23), the center of the sixth protrusion (15f) is located between the center of the fourth protrusion and the top end (23) of the second support surface (6), and wherein, in the top view of the first support surface (5) directly toward the blade holder (4), the imaginary straight line (L2) in the direction of the second force component from the center of the recess (14) intersects the sixth protrusion (15f).

15. The cutting tool (1) according to any one of the preceding claims, characterized in that, Each of the protrusions (15a-15f) is formed with a convex contact surface, thereby being configured to provide a precise contact point with the associated surface (9, 10) that abuts against the cutting blade (7) and contacts the convex contact surface.

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