EP3867001A1

EP3867001A1 - Tool holder and tool having a tool holder of this kind

Info

Publication number: EP3867001A1
Application number: EP19790171.3A
Authority: EP
Inventors: Matthias Luik
Original assignee: Hartmetall Werkzeugfabrik Paul Horn GmbH
Current assignee: Hartmetall Werkzeugfabrik Paul Horn GmbH
Priority date: 2018-10-17
Filing date: 2019-10-15
Publication date: 2021-08-25
Also published as: US20210220921A1; WO2020078997A1

Abstract

The invention relates to a tool holder (12) for a tool (10) for machining a workpiece, comprising: a cutting insert receptacle (18) for receiving a cutting insert (14), wherein the cutting insert receptacle (18) has an upper clamping jaw (20) for contacting a top side (24) of the cutting insert (14) and a lower clamping jaw (22) for contacting a bottom side (26) of the cutting insert (14) opposite the top side (24); and an internal coolant channel (36), which extends in the interior of the tool holder (12) between a coolant inlet opening (38) and a coolant outlet opening (40), wherein an end portion (56) of the coolant channel (36), said end portion extending in the interior of the upper clamping jaw (20) along a channel centre axis (62), opens into the coolant outlet opening (40); wherein the coolant outlet opening (40) is arranged on the upper clamping jaw (20) and is designed as an elongate opening, wherein a width (b_i) of the coolant outlet opening (40) is less than a height (h₁) of the coolant outlet opening (40), measured orthogonally to the width (b_i) of the coolant outlet opening (40), and wherein the end portion (56) of the coolant channel (36) is also designed elongately in a cross-section orthogonal to the channel centre axis (62), wherein a width (62) of the end portion (56), measured orthogonally to the channel centre axis (62), is less than a height (h₂) of the end portion (56), measured orthogonally to the channel centre axis (62) and orthogonally to the width (62) of the end portion (56).

Description

Tool holder and tool with such a tool holder

The present invention relates to a tool holder for a tool for cutting

Machining a workpiece. The present invention also relates to the tool which has the tool holder according to the invention and a cutting plate arranged on the tool holder.

The tool according to the invention is preferably designed as a turning tool.

The tool according to the invention is particularly preferably a turning tool which is used for plunge and parting off.

The tool according to the invention or the tool holder according to the invention can be designed, for example, as a stabbing sword. As an alternative to this, the tool holder of the tool according to the invention can also be designed as a tool holder cassette, which is used in a known manner in a CNC lathe. Independent depending on whether the tool holder according to the invention has the shape of a piercing sword or is designed in the form of a tool holder cassette, the tool according to the invention is preferably used for plunge turning with very narrow plunge widths. The insert holder of the tool holder and the insert inserted therein are therefore preferably designed to be comparatively narrow in order to permit such machining (narrow plunge widths).

A particular challenge when turning narrow groove widths is the supply of the coolant and lubricant (hereinafter simply referred to as "coolant"). In order to guarantee the best possible cooling and lubrication of the cutting plate which is in engagement with the workpiece, the coolant should reach the machining point as precisely as possible within the insertion tool to be produced.

Due to the comparatively narrow design of the tool holder

In the area of the cutting plate in particular, the coolant channels usually provided in such tools in the interior of the tool holder must therefore be made very small. On the other hand, however, this limits the amount of coolant supply per unit time.

[0006] EP 3 103 573 A1, for example, describes a stab sword with an internal one

Coolant channel known that emerges from the tool holder of the lancing sword above the cutting plate. Another pricking sword with an internal coolant channel is known from DE 81 26 791 A1.

In the two stab swords mentioned above, the coolant outlets are made relatively small for the reasons mentioned above. In order to be able to supply the processing point with sufficient coolant, the coolant must therefore be subjected to a very high pressure. In addition, it is relatively difficult to align the very small coolant outlet so precisely that the resulting, very fine coolant jet is aimed in the desired manner at the processing point. It would therefore be desirable to have the coolant outlet despite the very narrow

Design of the tool holder in the area of the insert holder to be provided somewhat larger in order to be able to increase the quantity of coolant per unit of time and to generate a coolant jet which is not quite as fine.

With this in mind, it is an object of the present invention to provide a

To provide a tool holder and an associated tool, which is particularly suitable for machining narrow plunge widths and to ensure an improved coolant supply to the machining point at which the cutting plate comes into engagement with the workpiece to be machined compared to the prior art.

According to the invention this object is achieved by a tool holder, the following

Features:

a cutting plate receptacle for receiving a cutting plate, the cutting plate receptacle having an upper clamping jaw for contacting an upper side of the cutting plate and a lower clamping jaw for contacting an underside of the cutting plate opposite the upper side; and

an internal coolant channel which extends in the interior of the tool holder between a coolant inlet opening and a coolant outlet opening, an end section of the coolant channel running inside the upper clamping jaw along a central channel axis opening into the coolant outlet opening;

wherein the coolant outlet opening is arranged on the upper jaw and is configured as an elongated opening, a width of the coolant outlet opening being less than a height of the coolant outlet opening measured orthogonal to the width of the coolant outlet opening, and

wherein the end section of the coolant channel is also elongated in a cross section orthogonal to the channel center axis, wherein a width of the end section measured orthogonal to the channel center axis is less than a height of the end section measured orthogonal to the channel center axis and orthogonal to the width of the end section. Furthermore, the above object is achieved according to the invention by a tool with such a tool holder and an insert inserted into the insert holder.

The present invention is characterized in particular by the manner in which

End section of the coolant channel and the coolant outlet opening, into which the end section of the coolant channel opens, are configured. Both the end portion and the coolant outlet opening have an elongated shape, the width of which is less than its height.

In this way, both the end portion of the coolant channel and the

Make the coolant outlet opening as large as possible, even if the upper clamping jaw of the tool holder is very narrow. As a result, a comparatively large amount of coolant can escape from the coolant outlet opening even if the upper clamping jaw is very narrow. The machining point, that is to say the point at which the cutting insert comes into contact with the workpiece to be machined, can therefore be supplied with coolant adequately well even with turning tools for machining very narrow plunge widths.

[0014] The width and height of the end section mentioned relate here to the

Geometric dimensions of the end section which are aligned orthogonally to one another and which have the cross section of the end section which is aligned orthogonally to the central channel axis.

[0015] In the present case, the central channel axis is understood to mean the central axis which is centered in the

End portion of the coolant channel is arranged and along which the coolant channel extends longitudinally.

The end portion of the coolant channel is preferably not curved. The

In other words, the channel center axis is a straight line in the region of the end section of the coolant channel, which runs centrally along the end section of the coolant channel. The cross section of the end section oriented orthogonally to the central channel axis Section can, but does not have to be mirror-symmetrical to the channel center axis.

According to one embodiment, the height of the end section along the

Channel center axis to the coolant outlet opening.

In other words, the closer the coolant channel approaches the coolant outlet opening, the more its height increases. The coolant jet emerging from the coolant channel is thus fanned out in the region of the end section along the height of the end section. The resulting comparatively highly diversified coolant jet, which leaves the coolant outlet opening, can supply a relatively large part of the groove to be produced with the tool with coolant.

[0019] Preferably, the height of the end section increases along the central channel axis

Coolant outlet opening continuously. Compared to a discontinuous, abrupt increase (for example an increase in steps), such a continuous increase in the height of the end section of the coolant channel is of great advantage from a fluid dynamic point of view, since it produces no or at least only very slight turbulent flows in the coolant channel flow.

According to a further embodiment, the coolant outlet opening is arranged in a plane which is oriented at an acute angle to a longitudinal axis of the holder, along which the tool holder extends longitudinally.

In other words, the front of the upper jaw, on which the coolant outlet opening is arranged, extends obliquely to the longitudinal axis of the holder. This oblique position or beveling of the coolant outlet opening alone would automatically result in an elongated coolant outlet opening, the width of which is smaller than its height, even in the case of a coolant channel with a circular cross section. In the tool holder according to the present invention, however, as already mentioned, the end section of the coolant channel is also elongated, so that this oblique arrangement of the Coolant outlet opening additionally reinforces the elongated shape that is already present.

[0022] The central channel axis preferably runs obliquely or at an acute angle to the longitudinal axis of the holder, so that the coolant jet emerging from the coolant outlet opening is directed obliquely from above in the direction of the cutting insert. The plane in which the coolant outlet opening is arranged preferably also runs obliquely or at an acute angle to the channel center axis.

According to a preferred embodiment, the coolant outlet opening is oval.

[0024] In the present case, “oval” is not only understood to be egg-shaped or elliptical. In the present sense, "oval" also means a shape that resembles the shape of a running track in a light athletics stadium.

According to a further preferred embodiment, the oval coolant outlet opening is formed by two parallel, straight flanks and two arcuate sections which adjoin opposite ends of the straight flanks.

[0026] Such an oval shape has the particular advantage that there are no sharp-edged corners that could lead to turbulence within the coolant flow, and that at the same time a coolant jet which is fanned out in height but directed can be generated.

[0027] According to a further embodiment, an initial section of the coolant channel, which adjoins the coolant inlet opening, has a circular cross section.

[0028] The coolant channel therefore preferably runs on the inside of the tool holder

Section with a circular cross section into a section with an elongated cross section. The initial section is preferably arranged within a base body of the tool holder, the width of which is greater in comparison to the upper clamping jaw. A coolant channel section with a circular cross section is in this part of the tool Holder preferred because the coolant channel does not have to be narrow in this area and thus the volume of the coolant channel or the initial section of the coolant channel can be increased due to the circular cross section. The start section of the coolant channel is preferably longer than the end section of the coolant channel. It therefore forms the majority of the coolant channel.

[0029] In an alternative embodiment, however, the entire coolant channel, that is to say including the initial section of the coolant channel, is of elongated or oval design. This is particularly advantageous when the tool holder is designed as a piercing sword, since piercing sword tool holders are usually designed to be very narrow over their entire length in order to enable very large piercing depths.

In the case of the design of the initial section of the coolant channel with a

circular cross section, the diameter of the cross section of the start section is preferably larger than the width of the end section, but smaller than the height of the end section.

In this embodiment, the coolant channel tapers in the width direction between the

Start section and end section. This results in a kind of nozzle effect through which the coolant jet is accelerated in the width direction and thus focused in the width direction. In contrast, as already mentioned above, the coolant jet is fanned out in the vertical direction.

According to a further embodiment, a central section of the coolant channel, which connects the starting section to the end section, has a circular cross section at its first end adjoining the starting section and an elongated cross section at its second end adjoining the end section, the Cross section of the middle section between the first end and the second end changes in a steady course. The middle section thus serves as a type of transition section through which said cross-sectional change of the coolant channel is generated. The cross section, which is constantly changing in the middle section, is again advantageous from a fluid dynamic point of view.

Such a complex shaped coolant channel, as it is for the

The beginning section, the middle section and the end section, as well as their transitions, can advantageously be produced in particular by additive manufacturing. The tool holder is therefore preferably manufactured as a whole by means of additive manufacturing. In this additive manufacturing, the coolant channel is also created in the additive manufacturing step. A subsequent creation of the coolant channel would otherwise be very expensive in the form mentioned.

[0035] According to a further embodiment, the end section is inside the upper one

The jaw is arranged, whereas the middle section and the starting section are arranged inside the tool holder, but not inside the upper jaw.

[0036] The initial section of the coolant channel is preferably curved.

The initial section particularly preferably has a curvature which changes continuously along the coolant channel course. Here, too, there are preferably no corners which cause turbulent flows in the coolant flow. Without the previously mentioned additive manufacturing, by means of which the tool holder is preferably manufactured, such a continuously curved coolant channel would hardly be possible. With additive manufacturing of the tool holder, however, this is easily possible.

[0037] According to a further embodiment, the tool holder has at least one bore, the coolant channel running inside the tool holder around the at least one bore.

[0038] With a curved configuration of the initial section of the coolant channel, it is possible without problems to wind the coolant channel around the bores, so to speak. According to a further embodiment, the coolant channel has a second one

Coolant outlet opening, which is arranged in the lower jaw or below.

[0040] The cutting insert can thus also be cooled from below. In this configuration

The coolant leaves the tool holder both above the cutting plate (at the first coolant outlet opening) and below the cutting plate (at the second coolant outlet opening). The second coolant outlet opening is preferably also connected to the coolant inlet opening. The coolant channel therefore branches preferably within the tool holder.

The second coolant outlet opening can be arranged in the lower jaw, particularly preferably the second coolant outlet opening is arranged on a protruding base of a so-called support, which is arranged below the lower jaw (i.e. on the side facing away from the upper jaw) .

It is understood that the above and those below

explanatory features can be used not only in the respectively specified combination, but also in other combinations or on their own, without leaving the scope of the present invention.

An exemplary embodiment of the invention is shown in the drawings and is explained in more detail in the description below. Show it:

1 shows a perspective view of an embodiment of the tool according to the invention;

Fig. 2 is an exploded view of the tool shown in Fig. 1; 3 shows a side view of the tool shown in FIG. 1, the tool holder of the tool being shown partially transparently in order to illustrate the interior thereof;

Fig. 4 is a top plan view of the tool shown in Fig. 1, the

Tool holder of the tool is shown partially transparent to illustrate its interior;

Fig. 5 is a perspective view of the tool shown in Fig. 1, wherein the

Fig. 6 is a sectional view of the tool shown in Fig. 1; and

7 shows a detailed view of a coolant outlet of the tool holder according to the invention in a top view from the front.

1-7 show several views of an embodiment of the

tool according to the invention. The tool is designated in its entirety by reference number 10 in the drawings.

The tool 10 has a tool holder 12 and a clampable therein

Cutting plate 14 on. In the exemplary embodiment shown here, the tool holder 12 is designed as a tool holder cassette which can be clamped in a machine tool, for example a CNC lathe. The clamping in the machine tool typically takes place via a plurality of clamping means which engage in bores 16 which are provided for this in the tool holder 12.

An advantage of such tool holder cassettes is that there are several

Tool holder cartridges of different types, which are suitable for different types of turning operations, for example, can be easily attached to the machine tool leave, so that, depending on the type of machining required, you can quickly switch between the different tools.

The tool holder 12 according to the embodiment shown in FIG. 1 has in

Area of its front end on a cutting plate receptacle 18 for receiving and releasably attaching the cutting plate 14. The insert holder 18 is formed by an upper jaw 20 and a lower jaw 22. The two jaws 20, 22 are spaced apart. There is an intermediate space between them which defines the insert holder 18. When the tool 10 is assembled, the cutting plate 14 is arranged in this intermediate space and clamped between the upper clamping jaw 20 and the lower clamping jaw 22. The upper jaw 20 lies against an upper side 24 of the cutting plate 14. The lower clamping jaw 22 rests on an underside 26 of the cutting plate 14 opposite the upper side 24.

In the exemplary embodiment shown here, a is in the tool holder 12

Separation slot 28 is provided. This separating slot 28 separates the upper jaw 20 from the lower jaw 22. The separating slot 28 enables at least partially elastic mobility of the two jaws 20, 22 relative to one another. In order to generate an additional clamping force by means of which the cutting plate 14 is clamped in the cutting plate receptacle 18, the tool 10 in the exemplary embodiment shown here has a clamping screw 30 which passes through the separating slot 28 into a provided in the tool holder 12 Internal thread 32 is screwed. By screwing the clamping screw 30 into the internal thread 32, the upper jaw 20 is moved in the direction of the lower jaw 22, so that the height of the insert holder 18 is reduced and the clamping force exerted on the insert 14 is increased. To release the cutting plate 14 from the tool holder 12, the clamping screw 30 must then be loosened accordingly.

In the exemplary embodiment shown here, the clamping screw 30 is used orthogonally to a longitudinal axis 34, along which the tool holder 12 extends longitudinally. However, it goes without saying that this does not necessarily have to be the case. For example, the clamping screw 30 could also be at an acute angle to the Insert the longitudinal axis 34 into the tool holder 12. Embodiments are also conceivable in which such a clamping screw 30 is dispensed with entirely. In such exemplary embodiments, the pretension between the upper jaw 20 and the lower jaw 22 is sufficient to exert a sufficiently large clamping force on the cutting plate 14. To loosen or replace the cutting plate, an expansion key must then usually be used, with the aid of which the cutting plate receptacle 18 is expanded in order to be able to remove the cutting plate 14 from the tool holder 12.

The tool holder 12 also has a coolant channel 36 in its interior,

which can be seen in particular in FIGS. 3-5. This coolant channel 36 serves to guide coolant or lubricant, which is usually subjected to a high pressure and is sprayed into the area of the cutting plate 14, that is to say into the area of the machining point of the workpiece, during use of the tool 10 . The coolant channel 36 extends between a coolant inlet opening 38 and a coolant outlet opening 40. The coolant outlet opening 40 is arranged on the upper clamping jaw 20 in order to thereby direct coolant onto the cutting plate 14, preferably obliquely from above.

In the exemplary embodiment shown here, the coolant channel 36 has a

further coolant outlet opening 42, which is referred to in the present case as the second coolant outlet opening 42. However, this second coolant outlet opening 42 is only an optional feature of the tool 10 according to the invention. The second coolant outlet opening 42 is arranged below the insert holder 18. More specifically, the second coolant outlet opening 42 is arranged in the exemplary embodiment shown here on a protruding projection of a so-called support 44 which adjoins a lower end of the lower jaw 22 and carries the lower jaw 22 or mechanically stabilizes it. The coolant channel 36 branches inside the tool holder 12 at a branch point 46 into a first partial channel 48, which opens into the coolant outlet opening 40, and a second partial channel 50, which opens into the second coolant outlet opening 42. As already mentioned, the second subchannel 50 and the second coolant outlet opening 42 can in principle also be omitted without the frame of FIG to leave the present invention. In the following, the design of the first subchannel 48 of the coolant channel 36 is therefore mainly discussed in more detail.

The coolant channel 36, in particular its first sub-channel 48, winds through the interior of the tool holder 12 (see in particular FIGS. 3-5). It runs around the bores 16 and around the clamping screw 30. The coolant channel 36 is therefore curved at several points. The coolant channel 36 particularly preferably has a continuously changing curvature along its course. So it preferably has no sharp corners, abrupt or step-like shoulders. This is particularly advantageous from a fluid dynamic point of view, since it can be used to avoid or at least reduce undesirable turbulent flows within the coolant channel 36.

The coolant channel 36, in particular its first subchannel 38, has several

Sections, which are referred to herein as the start section 52, middle section 54 and end section 56.

The initial section 52 forms the first section of the coolant channel 36 or its first channel part 48. It adjoins the coolant inlet opening 38 and extends over a large part of the length of the coolant channel 36. In this initial section 52, the coolant channel 36 preferably has a circular shape Cross section on.

The end section 56 forms the other end of the first partial channel 48 of the

Coolant channel 36. The end section 56 is arranged in the upper jaw 20 and opens into the coolant outlet opening 40. The end section 56 of the coolant channel 36 as well as the coolant outlet opening 40 each form an elongated cross section, the width of which is smaller than the height measured orthogonally thereto.

The middle section 54 of the coolant channel 36 forms the transition between the

Start section 52 and end section 56. A first end of middle section 54 thus adjoins start section 52 and a second, opposite end of middle section 54 adjoins end section 56. The middle section 54 is as well as the initial section 52 preferably within the base of the

Tool holder 12, that is not arranged in the upper jaw 20. Preferably, only the end portion 56 is located within the upper jaw 20. The transition between the middle section 54 and the end section 56 thus preferably takes place in the region of the transition between the base body of the tool holder 12 and the upper clamping jaw 20.

A feature of the present invention relates to the type of configuration of the

Coolant outlet opening 40 and the adjoining end section 56 of the coolant channel 36.

The coolant outlet opening 40, which is arranged on the upper jaw 20, is designed as an elongated opening, the width bi of which is less than the height h-i measured orthogonally thereto (see in particular FIG. 7). The coolant outlet opening 40 preferably has an oval shape. This oval shape can, for example, be elliptical or egg-shaped. In the exemplary embodiment shown here, however, the oval coolant outlet opening 40 has two mutually parallel flanks 58 and two arcuate sections 60, which adjoin opposite ends of the straight flanks 58. The arcuate sections 60 can be designed as semi-circles or as semi-ellipses. The rectilinear flanks 58 preferably merge into the arcuate sections 60 in a continuous course.

The end section 56 of the coolant channel 36 adjoining the coolant outlet 40 is also elongated. The end section 56 extends longitudinally along a central channel axis 62 which runs centrally or centrally along the end section 56 (see in particular FIG. 1). The end section 56 has an elongated cross section, in particular with respect to this central channel axis 62. More specifically, a width b _{2 of} the end section 56 measured orthogonal to the central channel axis 62 is less than a height h _{2 of} the end section 56 measured orthogonal to the central channel axis 62 and orthogonal to the width b ₂ (see in particular FIGS. 4 and 6). Thus, not only the coolant outlet opening 40, but also the end section 56 has an elongated, preferably oval shape. The coolant jet is therefore fanned out in the direction or parallel to the height hi and h ₂ and focused laterally along the width bi and b ₂ . This is particularly advantageous in the case of tools with comparatively narrow upper clamping jaws 20, which are used for machining plunge-cut tools with comparatively small plunge widths. Even in such a case, even when machining small plunge widths, a sufficiently large coolant flow can be guaranteed, which can be optimally used for cooling and lubricating the usually narrowly designed machining point.

The channel central axis 62 of the end portion 56 is preferably under an acute one

Angle aligned with the longitudinal axis 34 of the tool holder 12. In addition, the front of the upper jaw 20 is preferably beveled, so that the coolant outlet opening 40, which is arranged on this front of the upper jaw 20, is also oriented at an acute angle to the longitudinal axis 34 of the tool holder 12. The coolant jet emerging from the coolant outlet opening 40 thus occurs on the cutting plate 14 at an angle from above.

Preferably, the height hi of the end section 56 increases along the central channel axis 62 towards the coolant outlet opening 40 (see FIG. 6). The height h ₂ preferably increases continuously along the central channel axis 62. This advantageously contributes to the aforementioned fanning out of the coolant jet.

As can be seen from Fig. 4, the width b ₂ along the central channel axis 62 in

End portion 56 preferably constant.

The central portion 54 of the coolant channel 36 is shown in the present

Embodiment designed somewhat more complex. In this middle section 54, the coolant channel 36 changes from its initially circular cross section in the starting section 52 to the elongated or oval cross section described in the end section 56. The diameter d of the circular cross section of the coolant channel 36 in the starting section 52 is preferably larger than the width b _{2 of} the end section 56, but smaller than the height h _{2 of} the end portion 56. Accordingly, the cross section of the

Coolant channel 36 in the central section 54 in width, but increases in height. However, an increase of amount is not absolutely necessary, since the end portion 56 h in height at the transition to the central portion 54 ₂ can also be equal in size structured as the diameter d of the initial portion 52. In such a case, the coolant channel 36 would in its middle section 54, that is to say only to decrease in width, but not in height. This is possible because the height h ₂ of the coolant channel 36 in the end section 56 preferably increases in the direction of the coolant outlet opening 40, as already mentioned.

In such a relatively complex shaped coolant channel 36, as described above, the easiest and cheapest way to manufacture it is by additive manufacturing of the tool holder 12. The tool holder 12 is preferably produced as a whole by means of additive manufacturing.

Finally, it should be mentioned that the division of the coolant channel described above

36 in the start section 52, middle section 54 and end section 56 is not absolutely necessary. In particular, in the case of a configuration of the tool holder 12 with an overall small width, for example in the case of an embodiment of the tool holder 12 as a piercing sword, the coolant channel 36 can also be configured as a whole with an elongated or oval cross section. In such a case, a transition between a circular cross section and an oval or elongated cross section, as described above for the central section 54, can be dispensed with. The coolant channel 36 could then also be formed with a constant cross section (oblong or oval) that remains unchanged along the course of the channel. In principle, the coolant channel 36 can also be designed with a constant cross section in its end section 56 without its height h ₂ increasing in the direction of the coolant outlet opening 40. Further modifications, in particular with regard to the shape of the tool holder 12, are also possible without departing from the scope of the present invention. Additive manufacturing of the tool holder 12 is preferred, but not absolutely necessary.

Claims

1. Tool holder (12) for a tool (10) for machining a workpiece, comprising:

a cutting plate receptacle (18) for receiving a cutting plate (14), the cutting plate receptacle (18) having an upper clamping jaw (20) for bearing against an upper side (24) of the cutting plate (14) and a lower clamping jaw (22) Has contact with an underside (26) of the cutting plate (14) opposite the upper side (24); and

an internal coolant channel (36) which extends in the interior of the tool holder (12) between a coolant inlet opening (38) and a coolant outlet opening (40), an inside the upper clamping jaw (20) running along a central channel axis (62) End section (56) of the coolant channel (36) opens into the coolant outlet opening (40);

wherein the coolant outlet opening (40) is arranged on the upper jaw (20) and is designed as an elongated opening, wherein a width (bi) of the coolant outlet opening (40) is less than an orthogonal to the width (bi) of the coolant outlet opening (40) measured height (hi) of the coolant outlet opening (40), and

wherein the end section (56) of the coolant channel (36) is also elongated in a cross section orthogonal to the channel center axis (62), a width (b ₂ ) of the end section (56) measured orthogonal to the channel center axis (62) being less than is a height (h ₂ ) of the end portion (56) measured orthogonal to the central channel axis (62) and orthogonal to the width (62) of the end portion (56).

2. Tool holder according to claim 1, wherein the height (h ₂ ) of the end section (56) increases along the central channel axis (62) towards the coolant outlet opening (40).

3. Tool holder according to claim 1 or 2, wherein the coolant outlet opening (40) is arranged in a plane which is aligned at an acute angle (a to a longitudinal axis (34) along which the tool holder (12) extends.

4. Tool holder according to one of claims 1-3, wherein the coolant outlet opening (40) is oval.

5. Tool holder according to claim 4, wherein the oval coolant outlet opening (40) is formed by two parallel, straight flanks (58) and two arcuate sections (60), which adjoin opposite ends of the straight flanks (58) is.

6. Tool holder according to one of claims 1-5, wherein an initial section (52) of the coolant channel (36) which is adjacent to the coolant inlet opening (38) has a circular cross section.

7. Tool holder according to claim 6, wherein the start section (52) of the coolant channel (36) is longer than the end section (56) of the coolant channel (36).

8. Tool holder according to claim 6 or 7, wherein a diameter (d) of the circular cross-section of the start section (52) is larger than the width (b ₂ ) of the end section (56), but smaller than the height 8h ₂ ) of the end section (56).

9. Tool holder according to claim 8, wherein a middle section (54) of the coolant channel (36), which connects the start section (52) to the end section (56), has a circular end at its first end adjoining the start section (52) Cross section and at its second end adjoining the end section (56) has an elongated cross section, the cross section of the middle section (54) changing in a continuous course between the first end and the second end.

10. Tool holder according to claim 9, wherein the end section (56) is arranged inside the upper jaw (20) and the middle section (54) and the starting section (52) inside the tool holder (12), but not inside the upper jaw (20) are arranged.

1 1. Tool holder according to one of claims 6-10, wherein the starting portion (52) has a continuously changing along a coolant channel course curvature.

12. Tool holder according to one of claims 1-1 1, wherein the tool holder (12) has at least one bore (16) and the coolant channel (36) inside the tool holder (12) around the at least one bore (16).

13. Tool holder according to one of claims 1-12, wherein the coolant channel (36) has a second coolant outlet opening (42) which is arranged in the lower clamping jaw (22) or below.

14. Tool holder according to one of claims 1-13, wherein the tool holder (12) is produced by additive manufacturing.

15. Tool (10) for machining a workpiece, with the tool holder (12) according to one of claims 1-14 and a cutting insert (14) inserted into the insert holder (18).