Tools and cutting tools used for cutting processes; the use of these tools

Abstract

A cutting tool (100) is provided, comprising: a base member (1) having a rotation axis (R) about which the tool rotates during operation; at least one seat (2) formed in the base member (1) for receiving a replaceable cutting tool (3); a fixing screw (5) for fixing the cutting tool (3) to the seat (2); and the cutting tool (3) fixed to the seat (2). The seat (2) has a base surface (21) for supporting a lower side (33) of the cutting tool (3), a first side abutment surface (22) for supporting the cutting tool (3) radially inward, and a second side abutment surface (23) for supporting the cutting tool (3) in both axial and radially outward directions, and a hole (4) for receiving the fixing screw (5) is formed in the base surface (21). The hole (4) has a threaded hole (41) spaced at a distance from the base surface (21), and an unthreaded hole portion (42) in the direction closer to the bottom surface (21). The fixing screw (5) has a threaded portion (51) for engaging with a threaded hole (41), a head (53) for supporting in a through hole (36) of a cutting tool (3), and an unthreaded shaft portion (52) between the threaded portion (51) and the head (53), the unthreaded shaft portion (52) having a smaller cross-section than the unthreaded hole portion (42). The cutting tool (3) is fixed to the seat (2) such that the head (53) of the fixing screw (5) is supported on the through hole (36) of the cutting tool (3), the threaded portion (51) of the fixing screw (5) engages with the threaded hole (41), and the head (53) of the fixing screw (5) is elastically deflected such that when viewed in a direction perpendicular to the base plane (21), the unthreaded shaft portion (52) is supported in the second quadrant (Q2), which is axially positioned on the unthreaded hole portion (42) in a radially outward direction and along the direction of the free end (12) of the tool.

Description

Technical Field

[0001] This invention relates to a tool for cutting operations and the use of cutting tools on such a tool. Background Technology

[0002] In the machining of metal materials, and increasingly, composite materials, tools are typically used in which the cutting edge that moves to engage the workpiece is formed on a replaceable cutting tool made of a hard and wear-resistant material, and is mounted on a base member made of a harder material (e.g., tool steel) designed for this purpose. In this case, the replaceable cutting tool is typically in the form of a so-called indexable tool or indexable cutting tool, having multiple cutting edges that can be brought one after another to the working cutting position on the base member as the corresponding previous cutting edges wear. In this case, the cutting tool can typically be formed of hard metals (carbide), cermets, or ceramic cutting materials.

[0003] In tools configured for milling operations, the base member has an axis of rotation about which it rotates during tool operation. The base member may, for example, have only one holder for receiving a replaceable cutting tool. However, typically, multiple such holders are arranged in a distributed configuration around the circumference of the tool's base member. To increase productivity during cutting with such tools, there is a trend towards operating tools with suitable materials at increasingly higher speeds, configuring them as so-called high-speed milling machines or high-speed cutters, where speeds typically reach tens of thousands of revolutions per minute.

[0004] During the operation of such tools at very high speeds, problems arise not only from the cutting forces that typically occur and act primarily in the tangential and axial directions, but also, particularly, from the centrifugal forces acting on the cutting tool at high speeds. For the purposes of the terms radial, axial, and tangential in the following description, these terms in each case refer to the axis of rotation of the base component of the tool, unless other references can be derived from the specific context.

[0005] For example, when a cutting tool is fixed to a base by a retaining screw, high centrifugal force may cause the cutting tool to change position on the base component, and in extreme cases, may even cause the retaining screw to fail, thereby detaching the cutting tool from the base. If this occurs during a cutting operation, it may result in damage to the workpiece being machined and also pose a safety risk.

[0006] EP 1083017 A1 describes a cutting tool for high-speed machining, wherein a seat for accommodating a replaceable cutting tool is provided with a shape that cooperates to some extent with the underside of the cutting tool in a forced locking manner. Summary of the Invention

[0007] The object of the present invention is to provide an improved tool for cutting at high rotational speeds, an improved use of the cutting tool, and an improved method for fixing the cutting tool, wherein the cutting tool is reliably supported in a holder in a manner insensitive to production tolerances relative to active centrifugal force, and the clamping force for clamping the cutting tool can be predetermined within a narrow range.

[0008] This objective is achieved by a tool for cutting operations according to the invention. Advantageous improvements are described in other technical solutions.

[0009] The tool has a base member with a rotation axis about which it rotates during operation. At least one seat for receiving a replaceable cutting tool, a retaining screw for securing the cutting tool to the seat, and the cutting tool itself are formed on the base member. The seat has: a base surface for supporting the lower side of the cutting tool, a first abutment surface for abutting a first side of the cutting tool, and a second abutment surface for abutting a second side of the cutting tool, wherein the first abutment surface supports the cutting tool in a radially inward direction, and the second abutment surface supports the cutting tool in both axial and radially outward directions. A hole for receiving the retaining screw is formed in the base surface. This hole has a threaded hole spaced a distance from the base surface and an unthreaded portion closer to the base surface. The retaining screw has a threaded portion for engaging with the threaded hole, a head for supporting itself in a through-hole of the cutting tool, and an unthreaded shaft portion between the threaded portion and the head, the unthreaded shaft portion having a smaller cross-section than the unthreaded hole portion. The cutting tool is fixed to the seat such that the head of the fixing screw is supported on the through hole of the cutting tool, the threaded portion of the fixing screw mates with the threaded hole, and the head of the fixing screw is elastically deflected such that when viewed in a direction perpendicular to the base plane, the unthreaded shaft portion is supported in the second quadrant, which is axially positioned on the unthreaded hole portion in a radially outward direction and along the direction of the free end of the tool.

[0010] In the viewing direction perpendicular to the base plane, the hole has four quadrants. Two quadrants (the third and fourth quadrants) are located radially to the side, that is, closer to the axis of rotation of the base component, while two quadrants (the first and second quadrants) are located radially to the outside, that is, further away from the axis of rotation of the base component. The third quadrant, located radially to the inside, and the second quadrant, located radially to the outside, are each axially positioned along the direction of the tool's free end, and are referred to below as "axially in the front." The fourth quadrant, located radially to the side, and the first quadrant, located radially to the outside, are each positioned in a direction away from the tool's free end, that is, in the direction of the tool's clamping end, and are referred to below as "axially in the rear." Therefore, when viewed in a clockwise direction, there is a first quadrant that is radially outward from the free end, a second quadrant that is axially located radially outward in the direction of the free end, a third quadrant that is axially located radially inward in the direction of the free end, and a fourth quadrant that is radially inward from the direction of the free end.

[0011] Because the second abutment surface is configured to abut against the second side of the cutting tool, supporting the cutting tool in both the axial and radially outward directions, and because the fixing screw is elastically deflected, the unthreaded shaft portion is supported in the radially outer second quadrant, which is axially positioned on the unthreaded hole portion along the direction of the tool's free end. The cutting tool is supported in two positions spatially spaced apart by a forced locking mechanism against centrifugal force, thus reliably preventing the cutting tool from shifting off the holder during high-speed tool operation. Since the support of the unthreaded shaft portion on the unthreaded hole portion is achieved through the elastic deflection of the fixing screw head and the unthreaded shaft portion, the manufacturing tolerances of the first and second abutment surfaces, the hole, and the fixing screw can be reliably compensated for by the elastic deformation of the fixing screw. Furthermore, the clamping force for clamping the cutting tool onto the holder can be predetermined by the elastic characteristics of the clamping screw.

[0012] According to one improvement, the unthreaded shaft portion in the fourth quadrant is spaced apart from the unthreaded hole portion, the fourth quadrant being located in the radially inward direction and facing away from the free end of the tool. Therefore, the unthreaded hole portion has a correspondingly large excess size relative to the unthreaded shaft portion of the fixing screw, i.e., the hole portion is too large, allowing it to elastically deflect unimpeded until the unthreaded shaft portion abuts against the unthreaded hole portion in the quadrant located in the radially outward direction and the direction of the free end of the tool. In this way, tolerances of the cutting tool and the side abutment surface can be compensated particularly well. Preferably, the unthreaded shaft portion is also spaced apart from the unthreaded hole portion in the first and third quadrants.

[0013] When the head of the fixing screw is elastically deflected axially in the radially outward direction and in the direction of the free end of the tool, the cutting tool is clamped in a particularly reliable manner on the first abutment surface and the second abutment surface.

[0014] According to one improvement, the angle between the first and second abutment surfaces in the viewing direction perpendicular to the base plane is less than 75°. In this case, the cutting tool is surrounded in a particularly reliable and forcibly locked manner, and is thus fixed against active centrifugal force. Preferably, this angle is less than 65°. In this case, the angle surrounded by the first and second abutment surfaces is preferably greater than 35°, more preferably greater than 40°, so as to provide reliable enclosure of the cutting tool on the seat.

[0015] According to one improvement, the head of the retaining screw has a maximum cross-section perpendicular to the axis of the retaining screw, which is larger than the minimum cross-section of the through hole. In other words, in this case, the head of the retaining screw cannot be guided through the through hole of the cutting tool. In this case, the cutting tool is secured to the seat in a particularly reliable and forced-locking manner.

[0016] According to one improvement, the longitudinal axis of the threaded hole is offset relative to the longitudinal axis of the through hole in the contact plane between the head of the fixing screw and the through hole of the cutting tool in a direction toward the first abutment surface and in a direction toward the second abutment surface. In this case, the cutting tool is reliably clamped in the direction of the first abutment surface and the second abutment surface, while the unthreaded shaft portion of the fixing screw reliably abuts against the unthreaded hole portion by elastic deflection.

[0017] When the surface normal of the first side abutment surface has a radially outward direction component as its principal component, the first side abutment surface supports the cutting tool in a manner that is particularly reliable relative to radially inward forces. In addition to the radially outward direction component, the surface normal may also have smaller direction components in terms of axial and / or tangential values.

[0018] According to one improvement, the surface normal of the second abutment surface has an axial component and a radially inward component. In this case, the cutting tool is reliably supported by the second abutment surface relative to axial forces and relative to centrifugal forces. The surface normal of the second abutment surface can also have a small tangential component.

[0019] According to one improvement, the surface normal of the basal surface has a tangential component as its principal component. In this case, the cutting tool is supported on the base in a particularly reliable manner relative to the cutting force that mainly acts in the tangential direction. The surface normal of the basal surface may also have a small directional component in terms of its numerical value in the radial and / or axial directions.

[0020] According to one improvement, the wall of the unthreaded hole portion is constructed, at least in the second quadrant of the hole, to be concave on the hole side in the circumferential direction, which is located in the radially outward and axial directions of the tool's free end. In this case, the tolerances in the areas of the first and second side abutments and the mating cutting tool are compensated in a particularly reliable manner because the contact area of ​​the unthreaded shaft portion on the unthreaded hole portion and the elastic deflection of the head can be adjusted within a large angular range in the second quadrant.

[0021] According to one improvement, the unthreaded hole portion has a generally circular cross-section. In this case, the unthreaded hole portion can be constructed in a particularly simple and cost-effective manner. However, it is also possible to form an unthreaded hole portion with a cross-sectional shape different from a circular cross-section.

[0022] According to one improvement, the unthreaded hole portion is configured to be parallel to the threaded hole. This makes the production of the hole, and the fixing screw housed therein, particularly simple and cost-effective. Preferably, the unthreaded hole portion is configured to be coaxial with respect to the threaded hole.

[0023] According to one improvement, the tool is a high-speed end mill, configured for cutting operations at speeds exceeding 10,000 rpm. Reliably preventing active centrifugal forces is particularly important for tools configured for high-speed processing.

[0024] This objective is also achieved by using a cutting tool on such a tool according to the invention. In use, the advantages described above with reference to the tool are realized.

[0025] This objective is also achieved by the method for fixing the cutting tool according to the invention.

[0026] In a method for securing a cutting tool to a base member of a tool, the base member has a rotation axis about which the tool rotates during operation, and the base member has a base surface for supporting the lower side of the cutting tool, a first side abutment surface supporting the cutting tool in a radially inward direction, and a second side abutment surface supporting the cutting tool in both axial and radially outward directions. A hole for receiving a fixing screw is formed in the base surface, and the hole has a threaded hole spaced at a certain distance from the base surface, and an unthreaded portion of the hole in a direction closer to the base surface. The method includes the following steps:

[0027] - Place the cutting tool on the base so that its lower side is supported on the base surface, the first side is supported on the first side abutment surface, and the second side is supported on the second side abutment surface.

[0028] - The threaded portion of the guide screw passes through the through hole in the cutting tool and into the hole, causing the threaded portion to move to engage with the threaded hole, and the unthreaded shaft portion, positioned between the threaded portion and the head of the guide screw, rests in the unthreaded hole portion with circumferential spacing, and

[0029] - Screw the fixing screw in such that the head initially abuts against the through hole on the radially inner side away from the free end of the base member, and then the head elastically deflects against the unthreaded shaft portion in the radially outward direction and in the direction of the free end of the base, until it moves to abut against the second quadrant of the unthreaded hole portion, which is located in the radially outward direction and axially in the direction of the free end.

[0030] This method achieves the advantages described in the reference tool above. The advantageous improvements described in the reference tool can also be used advantageously with this method.

[0031] Other advantages and advantageous features of the present invention will be understood with reference to the embodiments described below and the accompanying drawings. Attached Figure Description

[0032] Figure 1 A perspective view of a tool according to one embodiment is shown;

[0033] Figure 2 It shows Figure 1 An enlarged view of the seat in the middle circle area B, which has a cutting tool mounted on it, but without fixing screws;

[0034] Figure 3 It shows the relationship with Figure 2 The corresponding diagram is shown, but no cutting tools are attached.

[0035] Figure 4 A schematic diagram of the fixing screw in this embodiment is shown;

[0036] Figure 5 A schematic cross-sectional view in a plane is shown, which includes the longitudinal axis of a threaded hole in the area of ​​the seat on which a cutting tool is mounted but no fixing screw is located;

[0037] Figure 6 A schematic perspective view of the cutting tool in this embodiment is shown;

[0038] Figure 7 It shows the relationship with Figure 5 The corresponding cross-sectional view shows the fixing screw in an untightened state;

[0039] Figure 8 It shows the relationship with Figure 7 The corresponding cross-sectional view shows the fixing screws in a tightened state;

[0040] Figure 9 A schematic cross-sectional view is shown in the unthreaded portion of the hole, perpendicular to the longitudinal axis of the hole, with the retaining screw in a detached state; and

[0041] Figure 10 It shows the relationship with Figure 9 The corresponding schematic cross-sectional view shows the fixing screws in a tightened state. Detailed Implementation

[0042] An embodiment will now be described in more detail with reference to the accompanying drawings.

[0043] In the specific embodiment shown, the tool 100 for cutting is in the form of a milling cutter, particularly a high-speed milling cutter, which is configured to perform machining at speeds of up to tens of thousands of revolutions per minute.

[0044] Tool 100 has a base member 1, which may be made of, for example, tool steel, such as... It is formed of tungsten heavy metal or hard metal. The base member 1 has a first end 11 and a free end 12. The first end is provided with an interface for indirect or direct connection to a drive shaft of a machining machine (not shown), and the free end faces away from the first end 11. The base member 1 has a rotation axis R about which the tool 100 rotates during operation, i.e., during the cutting operation.

[0045] like Figure 1 As shown, in the region of the free end 12 of the base member 1, a plurality of seats 2 for accommodating replaceable cutting tools 3 are provided. The seats 2 are arranged in a circumferential manner distributed on the base member 1. Although the embodiment specifically shown depicts a base member 1 with a total of four seats 2 for accommodating replaceable cutting tools 3, fewer such seats 2 may be provided, such as at least one, or more than four seats 2. The seats 2 are arranged such that, in each case, the cutting tool 3 disposed therein protrudes axially at the free end 12 of the base member 1 via an auxiliary cutting edge 31 and radially on the base member 1 via a main cutting edge 32. The seats 2 are configured for so-called radial clamping of the cutting tool 3, wherein the cutting tool 3 fixed to the respective seat 2 extends substantially radially in the main extension plane in each case, and the longitudinal axis of the fixing screw 5 extends primarily in the tangential direction, by which the cutting edge 3 is fixed to the seat. Since the various seats 2 are constructed to be substantially the same as each other, and the cutting tools 3 arranged on them are also at least substantially the same as each other, only one seat 2 and the cutting tool 3 fixed on it will be explained in more detail below.

[0046] The cutting tool 3 has a generally polygonal basic shape, with a lower side 33 and an upper side 34 opposite to the lower side 33, the upper side being in the form of a cutting surface, such as... Figure 6As shown. The lower side 33 and the upper side 34 are connected to each other via side surfaces. A through hole 36 extends from the upper side 34 to the lower side 33 through the cutting tool 3. An auxiliary cutting edge 31 and a main cutting edge 32 are constructed along the transition from the upper side 34 to the side surface and are connected to each other via a cutting angle 35. In the specifically illustrated embodiment, the cutting tool 3 has double rotational symmetry with respect to the longitudinal axis of the through hole 36, thereby providing two cutting edge portions, each having a main cutting edge 32 and an auxiliary cutting edge 31, the auxiliary cutting edge being connected to the main cutting edge via a cutting angle 35. Figure 1 As shown, with the cutting tool 3 assembled on the base member 1, one of the two cutting edge portions is in the active position, wherein the main cutting edge 32 protrudes radially beyond the base member 1 and the auxiliary cutting edge 31 protrudes axially beyond the base member 1, and the other of the two cutting edge portions is in the non-working position.

[0047] Although the cutting tool 3 is shown in the specific embodiment, in which the cutting edge portion is provided only at the transition from the upper side 34 to the side, in a variation, a double-sided construction of the cutting tool is also possible, in which the cutting edge portion is also provided at the transition from the lower side 33 to the side.

[0048] The cutting tool 3 has a first side surface 37, which is used to support the cutting tool 3 on the seat 2 in a radially inward direction. The first side surface 37 is formed on the cutting tool 3 on the side opposite to the main cutting edge 32 in the working position. Due to the aforementioned double rotational symmetry, there is an additional first side surface 37 below the main free surface of the main cutting edge 32 in the working position, which is associated with the main cutting edge 32 in the opposite non-working position.

[0049] The cutting tool 3 also has a second side surface 38, which supports the cutting tool 3 on the seat 2 in both axial and radially outward directions. The second side surface 38 is formed on the side of the cutting tool 3 opposite to the auxiliary cutting edge 31 in the working position. Due to the described double rotational symmetry, the side of the auxiliary cutting edge 31 in the working position also has an additional second side surface 38, which is associated with the auxiliary cutting edge 31 in the opposite non-working position.

[0050] The following will refer to Figure 3 The seat 2 that holds the cutting tool 3 is described in more detail.

[0051] The seat 2 has a base surface 21 for supporting the lower side 33 of the cutting tool 3, a first side abutting surface 22 for abutting against the first side 37 of the cutting tool 3, and a second side abutting surface 23 for abutting against the second side 38 of the cutting tool 3.

[0052] The surface normal of the base plane 21 has a tangential component as its principal component. In addition, the surface normal of the base plane 21 may also have small axial and / or radial components in terms of numerical value.

[0053] The first side abutment surface 22 supports the cutting tool 3 in the radially inward direction. The first side abutment surface 22 can be, for example, a continuous surface. However, for example, the first side abutment surface 22 can also have multiple separated partial surfaces for support in the radially inward direction, such as... Figure 3 As shown. To achieve support in the radially inward direction, the surface normal of the first abutment surface 22 has a radially outward direction component as its principal component. In this case, the surface normal of the first abutment surface 22 may, for example, have only a radially outward direction component, or additionally, may have smaller tangential and / or axial components in numerical terms.

[0054] The second abutment surface 23 supports the cutting tool 3 in both axial and radially outward directions on its side away from the free end 12 of the base member 1. To achieve this, the surface normal of the second abutment surface 23 has an axial component in the direction of the free end 12 of the base member 1 and a radially inward component. Furthermore, the surface normal of the second abutment surface 23 may also have a smaller tangential component, for example... Figure 3 The second side abutting surface 23 is shown.

[0055] like Figure 3 As shown, when viewed perpendicularly to the base surface 21, the first side abutment surface 22 and the second side abutment surface 23 together form an interior angle α of less than 75°, preferably less than 65°. In the specifically illustrated embodiment, the interior angle α is approximately 60°. The interior angle formed by the first side abutment surface 22 and the base surface 21 is ≥90°. The interior angle formed by the second side abutment surface 23 and the base surface is ≥90°. In the specifically illustrated embodiment, the interior angle between the base surface 21 and the first side abutment surface 22 is slightly greater than 90°, and for example, it can be approximately 100°. Similarly, the interior angle between the base surface 21 and the second side abutment surface 23 is slightly greater than 90°, and for example, it can be approximately 100°. In the case of a double-sided construction of the cutting tool 3, where the cutting edge portion is also formed at the transition from the lower side 33 to the side side, in each case, the interior angle between the base surface 21 and the side abutment surfaces 22, 23 can preferably be 90°.

[0056] like Figure 3 and Figure 5As shown, a hole 4 is formed on the base surface 21 of the seat 2. The hole 4 extends from the base surface 21 into the material of the base member 1 and has a threaded hole 41 in a region spaced apart from the base surface 21. This threaded hole has internal threads for engaging with the corresponding external threads of the fixing screw 5, which will be described in more detail below. A non-threaded hole portion 42 is formed between the threaded hole 41 and the opening of the hole 4 in the base surface 21. In the embodiment specifically shown, the non-threaded hole portion 42 has a circular cross-section and extends coaxially with respect to the threaded hole 41. However, the non-threaded hole portion 42 may also have a different cross-sectional shape.

[0057] like Figure 4 As shown, the fixing screw 5 has a threaded portion 52, a head 53, and an unthreaded shaft portion 52, wherein the threaded portion is configured to mate with a threaded hole 41, and the unthreaded shaft portion is disposed between the head 53 and the threaded portion 51. In the specifically illustrated embodiment, a tapered portion is provided between the threaded portion 51 and the unthreaded shaft portion 52, which facilitates relative elastic flexural bending of the head 53 relative to the threaded portion 51 in a direction perpendicular to the longitudinal axis of the fixing screw 5. The head 53 of the fixing screw 5 is configured to mate with a through hole 36 in the cutting tool 3. The head 53 has a maximum cross-section greater than the minimum internal cross-section of the through hole 36, such that the head 53 cannot extend completely through the through hole 36. The head 53 is adapted to the shape of the through hole 36 so that the head 53 can be supported on the through hole 36, particularly preferably in a ring-like manner. The cross-section of the unthreaded shaft portion 52 of the fixing screw 5 is significantly smaller than the cross-section of the unthreaded hole portion 42 of the hole 4. In other words, the unthreaded hole portion 42 has an extra dimension that completely surrounds the unthreaded shaft portion 52, which is significantly larger than the conventional tolerances produced with precise fit.

[0058] Especially Figure 3 As shown, the unthreaded hole portion 42 has four quadrants Q1, Q2, Q3, and Q4, which are numbered clockwise in this example. The first quadrant Q1 of the unthreaded hole portion 42 is located on the side of the unthreaded hole portion 42 facing outwards and away from the free end 12 of the base member 1. The second quadrant Q2 is located on the side of the free end 12 facing outwards and away from it. The third quadrant Q3 is also located on the free end 12, but on the side facing inwards and away from it. The fourth quadrant Q4 is located on the side of the unthreaded hole portion 42 facing outwards and away from it. In other words, the first quadrant Q1 is located between 12 o'clock and 3 o'clock, starting from a direction parallel to the rotation axis R; the second quadrant Q2 is located between 3 o'clock and 6 o'clock; the third quadrant Q3 is located between 6 o'clock and 9 o'clock; and the fourth quadrant Q4 is located between 9 o'clock and 12 o'clock.

[0059] refer to Figures 7 to 10The following will describe in more detail how to fix the cutting tool 3 to the seat 2 using the fixing screw 5.

[0060] First refer to Figure 7 and Figure 9 This describes a situation where a cutting tool 3 is positioned on a seat 2 and the threaded portion 51 of a retaining screw 5 is guided through the through-hole 36 of the cutting tool 3, such that the threaded portion 51 engages with a threaded hole 41, and a threadless shaft portion 52 is positioned within the threadless hole portion 42, but the retaining screw 5 is not yet tightened. In this state, the threadless shaft portion 52 is spaced apart from the threadless hole portion 42 on all sides, and the threadless hole portion has extra dimensions, particularly as... Figure 9 As shown. In other words, the unthreaded shaft portion 52 is spaced apart from the unthreaded hole portion 42 in the first quadrant Q1, the second quadrant Q2, the third quadrant Q3, and the fourth quadrant Q4. The longitudinal axis Z of the threaded hole 41 is slightly offset relative to the longitudinal axis W of the through hole 36 in the cutting tool in the direction of the first side abutment surface 22 and the second side abutment surface 23, for example... Figure 5 As shown. In Figure 2 In the diagram, arrow P (not to scale) schematically illustrates the direction of displacement of the longitudinal axis Z of the threaded hole 41 relative to the longitudinal axis W of the through hole 36. It can be seen that this direction extends at an angle β relative to the axial direction, such that it has a radially inward component and an axially rearward component in the direction of the first end 11 of the base member 1. In the specifically illustrated example, the angle β is, for example, between 50° and 70°.

[0061] When the fixing screw 5 is tightened, the threaded portion 51 is screwed deeper into the threaded hole, causing the head 53 of the fixing screw 5 to move to abut against the through hole 36 of the cutting tool 3. Due to the aforementioned offset between the longitudinal axis W of the through hole 36 and the longitudinal axis Z of the threaded hole 41, in this case, the head 53 first moves to abut against the region of the through hole 36 on one side between the first side abutment surface 22 and the second side abutment surface 23 of the seat 2. The cutting tool 3 is thus compressed in the direction between the first side abutment surface 22 and the second side abutment surface 23. Due to abutting against the through hole 36, the head 53 of the fixing screw 5 and the unthreaded shaft portion 52 elastically deflect in the radially outward direction and in the direction of the free end 12 of the base member 1, causing the unthreaded shaft portion 52 to deflect into the second quadrant Q2 of the unthreaded hole portion 42. This elastic deflection occurs until the unthreaded shaft portion 52 abuts against the unthreaded hole portion 42 in the second quadrant Q2 of the unthreaded hole portion 42. This state is as follows Figure 8 and Figure 10 As shown. In Figure 10The diagram schematically illustrates the offset of the longitudinal axis Y of the fixing screw 5 relative to the longitudinal axis Z of the threaded hole 41 in the region of the unthreaded shaft portion 52. In addition to being fixed in the radially outward direction by the second side abutment surface 23, the cutting tool 3 is thus forcibly locked in an additional position in the radially outward direction by the engagement of the unthreaded shaft portion 52 and the unthreaded hole portion 42, ensuring that the cutting tool 3 is reliably fixed relative to the centrifugal force acting during the cutting operation. Since the support is provided in the unthreaded shaft portion 52, the shear force caused by the centrifugal force does not act on the weaker threaded portion of the fixing screw 5, but rather on the substantially more stable unthreaded shaft portion 52, thereby reducing the risk of material failure of the fixing screw 5. Due to the elastic deformation of the fixing screw 5, the head 53 of the fixing screw 5 abuts against the through hole 36 in a forcibly locked manner. In this case, the larger head 53 of the fixing screw 5 engages with the smaller through hole 36 of the cutting tool 3 to reliably tighten the cutting tool 3 in the direction of the base surface 21, and to fix the cutting tool 3 in a forced locking manner to prevent it from being lifted off the base surface 21.

[0062] In the first quadrant Q1, third quadrant Q3, and fourth quadrant 4 of the unthreaded hole portion 42, when the fixing screw 5 is tightened, due to the extra dimensions of the unthreaded hole portion 42, the unthreaded shaft portion 52 of the fixing screw 5 does not abut, as... Figure 10 As shown. Through the elastic deformation of the fixing screw 5, until the unthreaded shaft portion 52 moves to abut against the unthreaded hole portion 42, the production tolerances of the cutting tool 3 and the first side abutment surface 22 and the second side abutment surface 23 can be easily compensated within a relatively large range. In this case, the tolerances of the position and orientation of the first side abutment surface 22 and the second side abutment surface 23 relative to each other are compensated by the unthreaded shaft portion 52 moving further in the direction of the free end 12 or further in the radially outward direction in the second quadrant Q2 of the unthreaded hole portion 42 to abut against it. The wall shape of the unthreaded hole portion 42 in the second quadrant Q2 is circumferentially concave on the hole side, so that the orientation of the unthreaded shaft portion 52 in this direction is not a problem in this case. Although the illustrated embodiment shows a circular cross-sectional shape for the unthreaded hole portion 42, which is particularly simple and cost-effective to manufacture, the cross-sectional shape of the unthreaded hole portion 42 is not limited to this circular shape, but may be other cross-sectional shapes. However, the wall of the unthreaded hole portion 42 should preferably be constructed to be concave in the circumferential direction, at least in the second quadrant.

Claims

1. A tool (100) for cutting operations, having The base component (1) has a rotation axis (R) about which the tool rotates during operation. At least one seat (2), formed on the base member (1), is used to accommodate a replaceable cutting tool (3). A fixing screw (5) is used to fix the cutting tool (3) to the seat (2), and A cutting tool (3) is fixed to the seat (2). in, The seat (2) has: a base surface (21) for supporting the lower side (33) of the cutting tool (3); a first side abutting surface (22) for abutting against the first side surface (37) of the cutting tool (3), the first side abutting surface (22) supporting the cutting tool (3) radially inward; and a second side abutting surface (23) for abutting against the second side surface (38) of the cutting tool (3), the second side abutting surface (23) supporting the cutting tool (3) in both axial and radially outward directions; and a hole (4) formed in the base surface (21) for receiving the fixing screw (5). The hole (4) has a threaded hole (41) spaced at a certain distance from the base surface (21), and has an unthreaded hole portion (42) in the direction closer to the base surface (21). The fixing screw (5) has a threaded portion (51) for engaging with the threaded hole (41), a head (53) for supporting in the through hole (36) of the cutting tool (3), and a threadless shaft portion (52) between the threaded portion (51) and the head (53), the threadless shaft portion (52) having a smaller cross-section than the threadless hole portion (42). The cutting tool (3) is fixed to the seat (2) such that the head (53) of the fixing screw (5) is supported on the through hole (36) of the cutting tool (3), the threaded portion (51) of the fixing screw (5) engages with the threaded hole (41), and the head (53) of the fixing screw (5) is elastically deflected such that when viewed in a direction perpendicular to the base plane (21), the unthreaded shaft portion (52) is supported in the second quadrant (Q2), which is axially positioned on the unthreaded hole portion (42) in a radially outward direction and along the direction of the free end (12) of the tool.

2. The tool according to claim 1, characterized in that, The unthreaded shaft portion (52) in the fourth quadrant (Q4) is spaced apart from the unthreaded hole portion (42), and the fourth quadrant is located in the radially inward direction and opposite to the free end (12) of the tool.

3. The tool according to claim 1 or 2, characterized in that, The head (53) of the fixing screw (5) is axially elastically deflected in the radially outward direction and in the direction of the free end (12) of the tool.

4. The tool according to claim 1 or 2, characterized in that, The angle (α) formed by the first side abutment surface (22) and the second side abutment surface (23) in the viewing direction perpendicular to the base surface (21) is less than 75°.

5. The tool according to claim 4, characterized in that, The angle (α) is less than 65°.

6. The tool according to claim 1 or 2, characterized in that, The head (53) of the fixing screw (5) has a maximum cross-section perpendicular to the axis of the fixing screw (5), which is greater than the minimum cross-section of the through hole (36).

7. The tool according to claim 1 or 2, characterized in that, The longitudinal axis (Z) of the threaded hole (41) is offset relative to the longitudinal axis (W) of the through hole (36) of the cutting tool (3) in the contact plane between the head (53) of the fixing screw (5) and the through hole (36) of the cutting tool (3) in the direction toward the first side abutment surface (22) and in the direction toward the second side abutment surface (23).

8. The tool according to claim 1 or 2, characterized in that, The surface normal of the first side abutment surface (22) has a radially outward direction component as the principal component.

9. The tool according to claim 1 or 2, characterized in that, The surface normal of the second side abutment surface (23) has an axial component and a radially inward direction component.

10. The tool according to claim 1 or 2, characterized in that, The surface normal of the base plane (21) has a tangential component as the principal component.

11. The tool according to claim 1 or 2, characterized in that, The wall of the unthreaded hole portion (42) is constructed, at least in the second quadrant (Q2) of the hole (4), to be concave in the circumferential direction on the hole side, the second quadrant being axially positioned in the radially outward direction and along the direction of the free end (12) of the tool.

12. The tool according to claim 1 or 2, characterized in that, The unthreaded hole portion (42) has a generally circular cross-section.

13. The tool according to claim 1 or 2, characterized in that, The unthreaded hole portion (42) is configured to be parallel to the threaded hole (41).

14. The tool according to claim 1 or 2, characterized in that, The tool (100) is a high-speed milling cutter configured to perform cutting operations at speeds exceeding 10,000 revolutions per minute.

15. Use of the cutting tool (3) on the tool (100) according to any one of claims 1 to 14.

16. A method for fixing a cutting tool (3) to a seat (2) of a base member (1) of a tool (100), in, The base member (1) has a rotation axis (R) about which the tool (100) rotates during operation, and the seat member (2) has a base surface (21) for supporting the lower side (33) of the cutting tool (3), a first side abutment surface (22) for supporting the cutting tool (3) in a radially inward direction, and a second side abutment surface (23) for supporting the cutting tool (3) in both axial and radially outward directions. In this design, a hole (4) for accommodating a fixing screw (5) is formed in the base surface (21), and the hole (4) has a threaded hole (41) spaced at a certain distance from the base surface (21), and has an unthreaded hole portion (42) in the direction closer to the base surface (21). The method comprises the following steps: - Place the cutting tool (3) on the seat (2), with its lower side (33) supported on the base surface (21), the first side (37) supported on the first side abutment surface (22), and the second side (38) supported on the second side abutment surface (23). - The threaded portion (51) of the guide screw (5) passes through the through hole (36) in the cutting tool (3) and enters the hole (4), causing the threaded portion (51) to move to engage with the threaded hole (41), and the unthreaded shaft portion (52) disposed between the threaded portion (51) and the head (53) of the guide screw (5) rests in the unthreaded hole portion (42) with a circumferential gap, and - Screw in the fixing screw (5) such that the head (53) initially abuts against the through hole (36) on the radially inner side away from the free end (12) of the base member (1), and then the head (53) elastically deflects against the unthreaded shaft portion (52) in the radially outward direction and in the direction of the free end (12) of the base member (1) until the unthreaded shaft portion (52) moves to abut against the second quadrant (Q2) of the unthreaded hole portion (42), which is located in the radially outward direction and axially in the direction of the free end (12).

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