Tool holder for machine tools

Abstract

A tool holder for a machine tool, having a holding assembly (3) rotatable about a rotation axis (R), to which a cutting tool (5) is detachably fixed or fixable, wherein the holding assembly (3) has at least two insertion openings (4) arranged in a circumferential manner offset to one another about the rotation axis (R), which are intended to accommodate a cutting tool (5) having an elongate insertion stem (6) and a cutting section (8), wherein each cutting tool (5) is fixed or fixable in the insertion opening (4) by means of an independent holding member (19), and wherein the cutting tools (5) delimit an accommodation space (9) for a workpiece to be jointly machined by the cutting tools (5) therebetween and with their cutting sections (8) facing the accommodation space (9).

Description

Technical Field

[0001] The present invention relates to a tool holder for a machine tool having a retaining assembly rotatable about a rotation axis, wherein the cutting tool is detachably fixed or can be fixed to the retaining assembly. Background Technology

[0002] Tool holders are used on various machine tools. A tool holder can typically rotate about a rotational axis in its mounting position. For this purpose, the tool holder is coupled to a drive member on the machine tool side, which rotates about the rotational axis, and the tool holder also rotates about this axis. On one hand, the tool holder has a retaining assembly through which it is coupled to the machine tool or its rotary drive, with different interfaces provided for this purpose, such as HSK interface (HSK = hollow taper shank) or SK interface (SK = large taper shank). The cutting tool used to machine the workpiece is fixed to the retaining assembly. An example application of this tool holder, or the machining that can be performed with it, is surface machining of long, cylindrical metal objects by cutting-type turning. By turning, the long, cylindrical metal object can be adjusted to a desired diameter, and the desired surface finish or surface quality can also be adjusted through this cutting-type turning. An example of such long, cylindrical workpieces or metal parts is a plug or pin used for electrical connectors. These plugs or pins are sometimes very thin, typically only a few millimeters in diameter. To achieve turning, long, cylindrical metal parts have so far been machined on lathes. The clamped metal part rotates and is turned using a cutting tool that approaches and moves along the metal part laterally. In this case, extreme caution is required because excessive lateral pressure generated by the cutting tool can cause the metal part to bend laterally. The thinner the metal object, the more severe this problem becomes. Summary of the Invention

[0003] The object of this invention is to provide a tool holder for machining workpieces that is an improvement over other options and, in particular, enables simple and safe turning of long, narrow workpieces.

[0004] With regard to the type of tool holder mentioned at the beginning, the solution of the present invention to achieve the above-mentioned objective is that the retaining assembly has at least two circumferentially offset insertion holes arranged around the axis of rotation, the insertion holes being used to receive cutting tools having elongated insertion rods and cutting sections, wherein each cutting tool is fixed or can be fixed in the insertion holes by an independent retaining member, and wherein the cutting tool defines a receiving space therebetween for a workpiece to be jointly processed by the cutting tools and its cutting section is oriented toward the receiving space.

[0005] The tool holder according to the invention is characterized by a retaining assembly on which two independent cutting tools can be precisely positioned, allowing simultaneous machining of an elongated workpiece housed therein, for example, turning. For this purpose, the retaining assembly has two independent insertion holes, into which the cutting tools can be inserted by means of an elongated insertion rod disposed at the cutting tool. The insertion rod is securely fixed to the retaining assembly by a suitable retaining member, such that each cutting tool is positioned and does not leave its working position during workpiece machining. In this case, at least two insertion holes located on the same pitch circle are preferably equidistantly staggered circumferentially about a rotation axis around which the tool holder rotates. When two insertion holes are used, these two holes are radially opposite each other, and since the cutting tools are preferably implemented in the same manner, the two insertion holes are also implemented in the same manner. Therefore, the two tools rotate symmetrically about the rotation axis, but are correspondingly staggered circumferentially.

[0006] Extending from the corresponding insertion section is a preferably elongated tool section, on which a cutting section is provided for cutting the workpiece. Two workpieces are circumferentially spaced from each other and radially spaced from the axis of rotation, thus creating a accommodating space between them. The workpiece to be processed is placed in this accommodating space for processing, i.e., the workpiece is immersed between the two cutting tools or their cutting sections. Because these cutting sections face the accommodating space they define, during processing, at least two rotating cutting tools or cutting sections simultaneously cut the fixed-position workpiece, which naturally increases processing speed. Furthermore, at least two cutting tools or cutting sections are also supported together on the workpiece. If two cutting tools are used, they are radially opposite each other; if multiple cutting tools are used, the angle depends on the number of cutting tools and preferably uses equidistant angular divisions. That is, during processing, no lateral force is applied to the workpiece due to the symmetrical support of the cutting tools on the workpiece, advantageously avoiding bending loads on the workpiece.

[0007] To position at least two tools, they are simply inserted into corresponding sockets via their insertion rods, wherein the bottom of the sockets is closed so that the insertion rods rest against the bottom of the container. The cutting tools are then secured accordingly by holding components. In other words, assembly and replacement of the cutting tools are both simple.

[0008] At least two insertion holes and cutting tools are provided, preferably arranged 180° apart circumferentially. However, it is preferable to have three insertion holes, preferably arranged 120° apart circumferentially, or four insertion holes, preferably arranged 90° apart circumferentially, along with corresponding cutting tools. That is, the workpiece can be cut simultaneously using three or four cutting tools. In the case of symmetrical indexing, these cutting tools are all symmetrically or with symmetrical force distribution supported on the workpiece housed therein. Besides symmetrical indexing, such as 120° or 90°, asymmetrical indexing can also be provided. In principle, more than four insertion holes can be constructed, thereby arranging more than four cutting tools, but this requires a corresponding increase in the pitch circle diameter for arranging the cutting tools, which in turn requires a corresponding increase in the accommodating space to process workpieces with larger diameters.

[0009] In an improved embodiment of the invention, each insertion hole can be defined by at least one clamping section, and the insertion rod of the corresponding cutting tool is clamped or can be clamped onto the at least one clamping section by the retaining member. The insertion hole is equipped with at least one specific clamping section or forms such a clamping section, clamping the insertion rod radially relative to the axis of rotation onto the clamping section, i.e., fixing the insertion rod onto the clamping section by the retaining member. The corresponding final cutting tool position is defined by the corresponding clamping section, so that each cutting tool is automatically and accurately positioned by means of the clamping contact of each insertion rod on the clamping section; therefore, the corresponding cutting section is also automatically and accurately positioned without additional adjustment or positioning. In particular, the initial radial clamping of each insertion rod, achieved by means of the corresponding retaining member, automatically positions it.

[0010] According to an advantageous improvement of the invention, the sockets can be configured to engage with each other facing the axis of rotation to form a common recess. Each socket must be implemented in the form of a corresponding groove on the retaining assembly, which is introduced into the end side of the retaining assembly. According to the invention, two or more sockets engage with the common recess, these sockets opening towards each other to form a central recess or groove. This groove ultimately expands radially for each socket, wherein a corresponding insertion rod engages in the corresponding socket. Therefore, the recess is provided with a radially extended portion facing outwards from the retaining assembly to form the corresponding socket.

[0011] In this case, the cross-section of the extension is preferably compatible with the cross-sectional shape of the cutting tool or the insert rod. That is, the cross-section of the extension used to at least partially form the socket is compatible with the cross-sectional section shape of the insert rod, i.e., they have the same shape, meaning they have shape-compatible geometry. The minimum clearance between the insert rod and the socket or extension is preferably a few hundredths of a millimeter, thereby achieving a tight fit of the insert rod in the socket. This tight fit or minimum clearance allows only a minimal degree of radial movement, through which the corresponding insert rod is radially clamped to the support section by means of a retaining member. In other words, when the insert rod is inserted into the corresponding socket, positional adjustment is almost completely achieved based on the shape compatibility with the minimum clearance, and this positional adjustment is accomplished by tensioning with the retaining member, in which the insert rod is clamped to the clamping section in a manner bridging the minimum clearance.

[0012] In this case, each radial extension is preferably formed by a drilled section, wherein each drilled section preferably extends more than 180°, and the end edge of each drilled hole forms a clamping section, to which a corresponding insert rod with a cross-sectional shape compatible with the drilled section can be clamped by a retaining member. Thus, the common recess is formed by a number of drilled holes corresponding to the number of cutting tools to be fixed, these drilled holes overlapping each other. If two cutting tools are to be fixed, two drilled holes are introduced, these two drilled holes overlapping each other, thereby forming a common recess with a figure-eight cross-sectional shape. If three drilled holes are introduced, these drilled holes also overlap to form a corresponding recess geometry with three circular extensions; in the case of four drilled holes, a geometry with four circular extensions is formed, and so on. In this case, these drilled holes can be positioned such that, viewed from the cross-section of the recess, these drilled holes have a wrap angle greater than 180° for the insert rod. Therefore, the cross-sectional section is also circular or partially cylindrical, with the insert rod enclosed in a partially circular drilled hole. In this case, the drilled sections exceeding 180°, i.e., the end edges of the corresponding drilled sections, form clamping sections, clamping the corresponding insert rods to these clamping sections. This ensures that each insert rod is symmetrically tensioned in two positions.

[0013] As an alternative to constructing a wrap angle >180° and forming the resulting clamping section, one or two mutually angled support surfaces can be provided on each insert rod. These insert rods are radially tensioned or supported relative to each other in the installation position by these support surfaces. Thus, the insert rods directly abut against each other via planar support surfaces. When using more than two cutting tools to be clamped, there should always be two such support surfaces forming the same angle relative to each other (120° for three cutting tools, 90° for four cutting tools, and so on, to produce the same indexing). This allows for approximately automatic centering or orientation during installation or tensioning, especially when the gap between each insert rod is minimal as described above.

[0014] As described above, each cutting tool or each insert rod is secured by an independent retaining member. Therefore, in an improved embodiment of the invention, a number of threaded holes, corresponding to the number of insertion holes, can be provided on the retaining assembly. These threaded holes communicate with the outer surface of the retaining assembly and the insertion holes, and are in the form of retaining members that screw into or can be screwed into the retaining screws of the insert rods. Tensioning of each insert rod is achieved by a corresponding retaining screw, thus enabling very simple securing, especially since, as mentioned above, the insert rods are movable within the insertion holes with a minimum clearance of only a few hundredths or a few tenths of a millimeter; therefore, only minimal movement of the retaining screws is required for tensioning.

[0015] In this case, each threaded hole preferably forms an angle of <90° with the axis of rotation. That is, the central axis of the threaded hole extends inclined to the bottom of the insertion hole or common recess. This allows the insertion rod and cutting tool to withstand the axial force generated by the inclined tightening through the retaining screw, which presses the insertion rod against the bottom of the insertion hole or common recess. In other words, this not only radially clamps the insertion rod and cutting tool to the clamping section of the insertion hole or alternatively to an adjacent insertion rod or support surface, but also axially clamps the insertion rod and cutting tool to the bottom of the insertion hole.

[0016] In this case, a planar thrust surface can be provided on each insertion rod, ensuring the screw strikes the thrust surface perpendicularly. If the threaded hole is perpendicular to the axis of rotation, the thrust surface can also be parallel to the axis of rotation. However, the threaded hole preferably forms an angle of <90° with the axis of rotation, as described above, so that the thrust surface also forms a corresponding angle. By screwing the corresponding retaining screw perpendicularly onto the thrust surface, any axial displacement can be prevented by the resulting axial stress, as the retaining screw is supported by the inclined thrust surface.

[0017] Furthermore, each threaded hole can communicate with a flat screw-in surface on its outer surface. This facilitates the introduction of the threaded hole into the retaining assembly. Each threaded hole is preferably a countersunk hole so that the corresponding screw head can be embedded.

[0018] As described above, the tool holder according to the invention, or the cutting tools therein, can be adapted to perform different types of cutting operations. However, it is particularly preferred that the cutting sections of these cutting tools are adapted to turn needle-shaped workpieces to form cylindrical workpiece surfaces. For this purpose, each cutting section can have an actual cutting area and an exit section connected to the cutting section at a small angle to the axis of rotation; that is, from the perspective of the feed, the corresponding cutting edge first has an actual cutting area, which then extends at the edge in the exit section at an angle of 0.2°-1°, preferably about 0.5°, thereby preventing the cutting tool or multiple cutting tools from getting stuck on the workpiece.

[0019] In addition to the tool holder itself, the present invention also relates to a machine tool comprising a drive mechanism having a receiving member rotatable about a rotation axis and a tool holder of the type described above that is received or can be received in the receiving member, the rotation axis of the tool holder coinciding with the rotation axis of the receiving member. The receiving member may have any interface, such as an HSK or SK interface, and the retaining assembly naturally also has a compatible corresponding interface geometry. Attached Figure Description

[0020] Other advantages and details of the present invention are described below in the embodiments and accompanying drawings. Wherein:

[0021] Figure 1 A perspective view of a tool holder according to the present invention, which includes a retaining assembly and a cutting tool fixed to the retaining assembly.

[0022] Figure 2 To maintain the side view of the component,

[0023] Figure 3 For along Figure 2 A front view showing the direction of arrow III.

[0024] Figure 4 For along Figure 3 A cross-sectional view along line IV-IV as shown.

[0025] Figure 5 For the retaining assembly with inserted cutting tool along Figure 2 A cross-sectional view showing the direction of line VV.

[0026] Figure 6 This is a side view of the cutting tool.

[0027] Figure 7 for Figure 6The view of the cutting tool shown is along the direction of arrow VII.

[0028] Figure 8 This is a top view of three cutting tools in their insertion position without retaining components.

[0029] Figure 9 A partial perspective view of three cutting tools with the retaining screw shown.

[0030] Figure 10 This is a schematic diagram showing the layout of two cutting tools relative to their insertion rods.

[0031] Figure 11 A schematic diagram of four cutting tools relative to their insertion rods, and

[0032] Figure 12 This is a schematic diagram of five cutting tools relative to their insertion rods. Detailed Implementation

[0033] Figure 1 A tool holder 1 designed according to the present invention is shown, which can be connected to the support socket of the drive unit of a machine tool in a known manner via a correspondingly designed fixing interface 2 (e.g., an HSK or SK connector). The tool holder 1 includes a retaining assembly 3 on which the mounting interface 2 is provided. In the example shown, it can rotate about a central rotation axis R in the mounting position (see...). Figure 3 The retaining assembly 3 has a total of four independent insertion holes 4, and the cutting tool 5 is inserted by means of the insertion rod 6 (see also for details). Figure 5 , 6 9) are inserted into these sockets and secured by suitable retaining members. The retaining sockets 4 are located circumferentially on the same pitch circle and are equidistantly distributed around the axis of rotation R in the example shown, thus with a graduation of 120°. In this case, each cutting tool 5 has a cutting extension 7 connected to the insertion section, on which cutting sections 8 in the form of cutting edges are respectively constructed. The cutting sections 8 (i.e., cutting edges) are spaced apart from each other and define a receiving space 9 therebetween, into which a nail-shaped or pin-shaped workpiece to be machined is inserted so that the workpiece can be machined by cutting through the cutting sections 8 (i.e., cutting edges), particularly turning.

[0034] like Figure 2 and Figure 3 As shown, the retaining component 3 is provided with a corresponding recess 10 at its end side, wherein the recess 10 is composed of three independent drill holes, wherein these drill holes, which are equidistant from each other by 120° around the rotation axis R, overlap to form Figure 3The recess shape is shown. In this case, the insertion hole 4 is segmented by corresponding radial extensions, the cross-section of which is necessarily circular due to the corresponding drilling. An insertion rod 6, whose circular shape with respect to the radial extension is implemented in a shape-compatible manner, is inserted into each circular insertion hole 4, thereby forming a shape fit. As described below, the insertion section is correspondingly implemented in a planar manner towards the center of the common recess 10, so that a roughly shape fit is also achieved there.

[0035] Each insertion hole 4 communicates with a threaded hole 11, which communicates with the outer side of the retaining assembly 3 and, therein, with the screw-in surface 12 of the plane. In this case, each threaded hole 11 (see in particular) Figure 4 ) and only Figure 4 The rotation axis R shown forms an angle α, where α < 90°. That is, the longitudinal axis of each threaded hole 11 is slightly inclined and faces the bottom 13 of each insertion hole 4, such that each insertion rod 6 and each cutting tool 5 are axially tensioned relative to the corresponding bottom 13 of the corresponding insertion hole 4 by screwing in the retaining screw, which will be described below.

[0036] Figure 5 To keep component 3 along Figure 2 A cross-sectional view along the direction of the VV line is shown, illustrating the inserted cutting tool 5 or insertion rod 6. A common recess 10 and corresponding insertion holes 4 are shown, each defined by a corresponding radial extension. As shown, the insertion holes 4 are formed by axially extending individual drill holes that overlap each other to form the common recess 10. Three corresponding insertion rods 6 for accommodating the cutting tools 5 are also shown, each forming a shape-fitting geometry relative to the circular extension, as shown. Figure 5 As shown, each insertion rod 6 has two corresponding surfaces 14 in the direction of the rotation axis R, and the included angle β between the two surfaces is 120°.

[0037] Figure 5It is also shown that each insertion hole 4 surrounds the corresponding insertion rod 6 at an angle >180° by means of its circular extension. That is, each insertion rod 6 is surrounded by the hole wall of the corresponding insertion hole 4 by more than 180°. Therefore, each insertion hole 4 formed by the corresponding drilled section 15 (corresponding to the extension) has two end edges 16, which serve as clamping sections, and each insertion rod 6 is radially clamped relative to these end edges by corresponding retaining screws. That is to say, the end edges 16 form the corresponding clamping sections due to the circumference of more than 180°, by which radial clamping sections can be easily achieved. Each insertion rod 6 is received in the corresponding insertion hole 4 with a minimum gap preferably a few hundredths of a millimeter, so that simple axial insertion can be made based on the small gap, but at the same time, tensioning with complete position fixation can be achieved in a very simple way by the corresponding retaining screws, since tensioning only requires bridging the minimum gap relative to the corresponding end edge 16 (i.e., the clamping section).

[0038] Figure 6 and Figure 7 These are side and front views of the cutting tool 5, respectively. One view shows the corresponding insertion rod 6 and the corresponding cutting extension 7 connected to it. As shown, each insertion rod 6 has a corresponding partially cylindrical rod surface 17, which corresponds to the geometry of the drilled section 15 of the insertion hole 4. Two planar rod surfaces 14 are connected to the corresponding partially cylindrical rod surfaces 17, as shown... Figure 5 The two planar rod surfaces form an angle β between them.

[0039] Figure 8 According to Figure 5 A top view of the layout of the three cutting tools in the illustrated embodiment. Also shown are corresponding cutting sections 8 in the form of corresponding cutting edges, which define accommodating spaces 9 therebetween.

[0040] Figure 9A partial view of the three cutting tools 5 and their insertion rods 6 in the installed position is shown, where the retaining assembly is not shown for clarity. Each insertion rod 6 has a planar thrust surface 18, and in the inserted position, a corresponding threaded hole 11 communicates adjacent to this thrust surface. A corresponding retaining screw 19 is also shown, which is screwed into the corresponding threaded hole 11 and abuts against the thrust surface 18. The thrust surface 18 is also at an angle to the axis of rotation R, where the corresponding angle ultimately corresponds to the tilt angle α of the threaded hole 11, so that each retaining screw 19 strikes the corresponding thrust surface 18 vertically. On the one hand, this achieves axial locking, i.e., completely preventing axial movement due to the inserted retaining screw 19. Furthermore, the tilted positions of the threaded hole 11 and the thrust surface 18 generate an axial component of force toward the corresponding bottom 13 of the insertion hole 4 and a radial component of force toward the end edge 16, such that the insertion rod 6 is clamped axially relative to the bottom region 13 and radially relative to the end edge 16 by screwing.

[0041] To assemble the retaining assembly 3, the three cutting tools 5 only need to be inserted into their respective sockets 4 by means of their insert rods 6. Due to the compatibility of the cross-section of the insert rod 6 with the given shape of the cross-section of the socket 4, mispositioning does not occur. The insert rods 6, housed in the sockets 4 with minimal clearance, are then tensioned by simply screwing the corresponding retaining screws 19 into the threaded holes 11 and tightening them onto the insert rods 6, thereby simultaneously achieving radial tension relative to the end edge 16 of the socket 4 or drilling section 15 in the direction of the axis of rotation, and axial tension relative to the corresponding bottom 13 of the socket 4. Since all the sockets 4 and their geometry are rotationally symmetric and preferably equidistant from the axis of rotation, as the cutting tools 5 are tensioned, the cutting sections 8, i.e., the corresponding cutting edges acting on the workpiece, will automatically and precisely position themselves relative to each other. In this case, the planes 14 of the insert rods 6 will not contact each other because the insert rods 6 are radially supported at the end edge 16, i.e., radially supported at the corresponding clamping section of each socket 4 or each drilling section 15, as described above. Leave a minimum gap of only a few hundredths of a millimeter.

[0042] In the example shown, the retaining component 3 has three sockets 4 for holding three cutting tools 5. Figure 10 , Figure 11 and Figure 12 Several embodiments are shown, illustrating the principles of different numbers of insertion holes 4 and cutting tools 5. Insertion rods 6 and their cross-sectional geometries are shown, wherein the cross-sectional geometry is identical to the cross-sectional geometry of the corresponding insertion hole 4.

[0043] exist Figure 10In the example shown, two insertion holes 4 and two cutting tools 5 can be positioned on the retaining assembly 3. The insertion holes 4 are located on the same pitch circle, offset by 180° around the axis of rotation R. Each insertion rod 6 is substantially cylindrical, and its surfaces facing each other are also planar. Here, the wrap angle of the insertion hole 4 or the drilled section 15 is also greater than 180°, such that the corresponding end edge 16 of the corresponding drilled section 15 forms a clamping section, relative to which the insertion rod 6 is clamped.

[0044] exist Figure 11 In the example shown, four insertion holes 4 are illustrated for four cutting tools 5. The insertion rods 6 each have correspondingly shape-compatible partially cylindrical rod faces, which respectively engage with two support surfaces at 90° angles relative to each other. In the example shown, the insertion rods 6 are supported by these two support surfaces, as a wrap angle of less than 180° is given here. Here, the insertion rods 6 are directly supported by each other. In this case, based on an extremely small clearance of only a few hundredths of a millimeter, all cutting tools 5 can be precisely positioned relative to each other effortlessly.

[0045] at last, Figure 12 An embodiment variant is shown with five sockets 4 for five cutting tools 5, wherein a corresponding geometry compatible with the shape of the respective socket 4 is given on the insertion rod 6. These planar support surfaces here form an angle of 72° with each other and also support each other, since no end edge is given as a clamping surface based on the small wrap angle.

Claims

1. A tool holder for a machine tool, having a retaining assembly (3) rotatable about a rotation axis (R), wherein at least two cutting tools (5) are detachably fixed to the retaining assembly, wherein, The retaining assembly (3) has at least two circumferentially offset insertion holes (4) arranged around the rotation axis (R), the insertion holes for receiving cutting tools (5) having elongated insertion rods (6) and cutting sections (8), wherein each cutting tool (5) is fixed in the insertion hole (4) by an independent retaining member (19), and wherein the cutting tool (5) defines a receiving space (9) therebetween for a workpiece to be jointly processed by the cutting tool (5) and its cutting section (8) faces the receiving space (9), characterized in that the insertion holes (4) are connected to each other facing the rotation axis (R) to form a common recess (10), wherein the recess (10) has a radial extension toward the outside of the retaining assembly (3) for forming a corresponding insertion hole (4), wherein the cross section of the extension is compatible with the cross section shape of the cutting tool (5), wherein each radial extension is formed by a drilled section (15).

2. The tool holder according to claim 1, characterized in that, It has three sockets (4) or four sockets (4).

3. The tool holder according to claim 1 or 2, characterized in that, Each jack (4) is defined by at least one clamping section, and the insertion rod (6) of the corresponding cutting tool (5) is clamped or can be clamped to the at least one clamping section by the retaining member (19), or the insertion rod (6) is clamped relative to each other by the retaining member (19).

4. The tool holder according to claim 1 or 2, characterized in that, Each drilled section (15) extends more than 180°, and the end edge (16) of each drilled section (15) forms a clamping section, through which a corresponding insert rod (6) with a cross-sectional shape compatible with the drilled section (15) can be clamped to the clamping section by the retaining member (19).

5. The tool holder according to claim 1 or 2, characterized in that, Each insertion rod (6) has at least one support surface, through which the insertion rod (6) is radially tensioned or supported relative to each other.

6. The tool holder according to claim 1 or 2, characterized in that, The retaining assembly (3) has a number of threaded holes (11) corresponding to the number of insertion holes (4). The threaded holes communicate with the outer surface of the retaining assembly (3) and the insertion holes (4), and are in the form of a retaining member (19) that abuts against the retaining screw of the insertion rod (6) and can be screwed into the threaded holes.

7. The tool holder according to claim 6, characterized in that, Each threaded hole (11) extends at an angle (α) of <90° with the axis of rotation (R).

8. The tool holder according to claim 6, characterized in that, Each insertion rod (6) has a planar thrust surface (18) on which the retaining screw strikes perpendicularly.

9. The tool holder according to claim 8, characterized in that, Each threaded hole (11) is opened on the planar screw-in surface (12).

10. The tool holder according to claim 6, characterized in that, The threaded hole (11) is a countersunk hole.

11. The tool holder according to claim 1 or 2, characterized in that, The cutting section (8) of the cutting tool (5) is designed for turning needle-shaped workpieces to form a cylindrical workpiece surface.

12. A machine tool comprising a drive device having a receiving member rotatable about a rotation axis and a tool holder (1) according to any one of the preceding claims, wherein the rotation axis (R) of the tool holder coincides with the rotation axis of the receiving member.

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