TOOL HOLDER AND TOOL

Abstract

A tool holder for a tool for machining a workpiece. The tool holder comprises a cutting insert receptacle for receiving a cutting insert, wherein the cutting insert receptacle comprises an upper clamping jaw for abutting an upper surface of the cutting insert and a lower clamping jaw for abutting a lower surface of the cutting insert opposite the upper surface. Further, the tool holder comprises an internal coolant channel extending inside the tool holder between a coolant inlet opening and a coolant outlet opening, wherein an end portion of the coolant channel extending inside the upper clamping jaw along a channel center axis opens into the coolant outlet opening. The coolant outlet opening is arranged at the upper clamping jaw and configured as an elongated opening. A width of the coolant outlet opening is smaller than a height of the coolant outlet opening measured orthogonally to the width of the coolant outlet opening. The end portion of the coolant channel is also elongated in a cross-section orthogonal to the channel center axis. A width of the end portion measured orthogonal to the channel center axis is smaller than a height of the end portion measured orthogonal to the channel center axis and orthogonal to the width of the end portion.

Claims

1. A tool holder for a tool for machining a workpiece, comprising: a cutting insert receptacle that is configured to receive a cutting insert, wherein the cutting insert receptacle comprises an upper clamping jaw that is configured to abut an upper surface of the cutting insert and a lower clamping jaw that is configured to abut a lower surface of the cutting insert opposite the upper surface; and an internal coolant channel extending inside the tool holder between a coolant inlet opening and a coolant outlet opening, wherein an end portion of the coolant channel extending inside the upper clamping jaw along a channel center axis opens into the coolant outlet opening; wherein the coolant outlet opening is arranged at the upper clamping jaw and configured as an elongated opening, wherein a width of the coolant outlet opening is smaller than a height of the coolant outlet opening measured orthogonally to the width of the coolant outlet opening, and wherein the end portion of the coolant channel is elongated in a cross-section orthogonal to the channel center axis, wherein a width of the end portion measured orthogonal to the channel center axis is smaller than a height of the end portion measured orthogonal to the channel center axis and orthogonal to the width of the end portion.

2. The tool holder according to claim 1, wherein the height of the end portion increases along the channel center axis toward the coolant outlet opening.

3. The tool holder according to claim 1, wherein the coolant outlet opening is arranged in a plane oriented at an acute angle to a holder longitudinal axis along which the tool holder extends.

4. The tool holder according to claim 1, wherein the coolant outlet opening is oval.

5. The tool holder according to claim 4, wherein the coolant outlet opening comprises two parallel straight flanks and two arcuate sections connected to opposite ends of the straight flanks.

6. The tool holder according to claim 1, wherein an initial portion of the coolant channel adjacent to the coolant inlet opening has a circular cross-section.

7. The tool holder according to claim 6, wherein the initial portion of the coolant channel is longer than the end portion of the coolant channel.

8. The tool holder according to claim 6, wherein a diameter of the circular cross-section of the initial portion is larger than the width of the end portion but smaller than the height of the end portion.

9. The tool holder according to claim 8, wherein a middle portion of the coolant channel connecting the initial portion to the end portion has a circular cross-section at a first end adjacent the initial portion and an elongated cross-section at a second end adjacent the end portion, wherein the cross-section of the middle portion varies continuously between the first end and the second end.

10. The tool holder according to claim 9, wherein the end portion is arranged inside the upper clamping jaw and the middle portion and the initial portion are arranged inside the tool holder but not inside the upper clamping jaw.

11. The tool holder according to claim 9, wherein the initial portion has a curvature that varies continuously along a coolant channel path.

12. The tool holder according to claim 1, wherein the tool holder comprises at least one bore, and wherein the coolant channel extends inside the tool holder around the at least one bore.

13. The tool holder according to claim 1, wherein the coolant channel comprises a second coolant outlet opening arranged in or below the lower clamping jaw.

14. The tool holder according to claim 1, wherein the tool holder is manufactured by additive manufacturing.

15. A tool for machining a workpiece, comprising: a tool holder having a cutting insert receptacle and an internal coolant channel extending inside the tool holder between a coolant inlet opening and a coolant outlet opening; and a cutting insert arranged in the cutting insert receptacle; wherein the cutting insert receptacle comprises an upper clamping jaw that is configured to abut an upper surface of the cutting insert and a lower clamping jaw that is configured to abut a lower surface of the cutting insert opposite the upper surface; wherein an end portion of the coolant channel extending inside the upper clamping jaw along a channel center axis opens into the coolant outlet opening; wherein the coolant outlet opening is arranged at the upper clamping jaw and configured as an elongated opening, wherein a width of the coolant outlet opening is smaller than a height of the coolant outlet opening measured orthogonally to the width of the coolant outlet opening, and wherein the end portion of the coolant channel is elongated in a cross-section orthogonal to the channel center axis, wherein a width of the end portion measured orthogonal to the channel center axis is smaller than a height of the end portion measured orthogonal to the channel center axis and orthogonal to the width of the end portion.

16. The tool holder according to claim 15, wherein the height of the end portion increases along the channel center axis toward the coolant outlet opening.

17. The tool holder according to claim 15, wherein the coolant outlet opening is arranged in a plane oriented at an acute angle to a holder longitudinal axis along which the tool holder extends.

18. The tool holder according to claim 15, wherein the coolant outlet opening is oval.

19. The tool holder according to claim 18, wherein the coolant outlet opening comprises two parallel straight flanks and two arcuate sections connected to opposite ends of the straight flanks.

20. The tool holder according to claim 15, wherein an initial portion of the coolant channel adjacent to the coolant inlet opening has a circular cross-section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIG. 1 shows a perspective view of an embodiment of the tool;

[0054] FIG. 2 shows an exploded view of the tool shown in FIG. 1;

[0055] FIG. 3 shows a side view of the tool shown in FIG. 1, wherein the tool holder of the tool is shown partially transparent to illustrate its interior;

[0056] FIG. 4 shows a top view of the tool shown in FIG. 1, wherein the tool holder of the tool is shown partially transparent to illustrate its interior;

[0057] FIG. 5 shows a perspective view of the tool shown in FIG. 1, wherein the tool holder of the tool is shown partially transparent to illustrate its interior;

[0058] FIG. 6 shows a sectional view of the tool shown in FIG. 1; and

[0059] FIG. 7 shows a detailed view of a coolant outlet of the tool holder in a top view from the front.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0060] FIGS. 1-7 show several views of an embodiment of the tool. In the drawings, the tool is denoted in its entirety by the reference numeral 10.

[0061] The tool 10 comprises a tool holder 12 and a cutting insert 14 that can be clamped therein. In the present embodiment, the tool holder 12 is configured as a tool holder cassette that can be clamped in a machine tool, for example in a CNC lathe. Clamping in the machine tool is typically done via a plurality of clamping means which engage in bores 16 that are provided for this purpose in the tool holder 12.

[0062] An advantage of such tool holder cassettes is that several tool holder cassettes of different types, which are e.g. suitable for different types of turning operations, can be easily attached to the machine tool so that, depending on the desired type of machining, it is possible to switch quickly between the different tools.

[0063] The tool holder 12 according to the embodiment shown in FIG. 1 comprises a cutting insert receptacle 18 in the area of its front end for receiving and detachably fastening the cutting insert 14. The cutting insert receptacle 18 is formed by an upper clamping jaw 20 and a lower clamping jaw 22. The two clamping jaws 20, 22 are spaced apart from each other. There is a space between them which defines the cutting insert receptacle 18. In the assembled state of the tool 10, the cutting insert 14 is arranged in this intermediate space and clamped between the upper clamping jaw 20 and the lower clamping jaw 22. The upper clamping jaw 20 abuts an upper surface 24 of the cutting insert 14. The lower clamping jaw 22 abuts a lower surface 26 of the cutting insert 14 opposite the upper surface 24.

[0064] In the present embodiment, a separation slit 28 is provided in the tool holder 12. This separation slit 28 separates the upper clamping jaw 20 from the lower clamping jaw 22. The separation slit 28 enables an at least partial elastic movement of the two clamping jaws 20, 22 relative to each other. To generate an additional clamping force by means of which the cutting insert 14 is clamped in the cutting insert receptacle 18, the tool 10 in the shown embodiment comprises a clamping screw 30 which is screwed through the separation slit 28 into an internal thread 32 provided in the tool holder 12. By screwing the clamping screw 30 into the internal thread 32, the upper clamping jaw 20 is moved in the direction of the lower clamping jaw 22, so that the height of the cutting insert receptacle 18 is reduced and the clamping force exerted on the cutting insert 14 is increased. To release the cutting insert 14 from the tool holder 12, the clamping screw 30 accordingly must then be loosened again.

[0065] In the present embodiment, the clamping screw 30 is inserted orthogonally to a longitudinal axis 34 along which the tool holder 12 longitudinally extends. However, it is clear that this does not necessarily need to be like this. For example, the clamping screw 30 could also be inserted into the tool holder 12 at an acute angle to the longitudinal axis 34. Likewise, embodiments are conceivable in which such a clamping screw 30 is dispensed with entirely. In such embodiments, the pretension between the upper clamping jaw 20 and the lower clamping jaw 22 is already sufficient to exert a sufficiently large clamping force on the cutting insert 14. To loosen or replace the cutting insert, it is then usually necessary to use an expanding wrench, by means of which the cutting insert holder 18 is expanded in order to be able to remove the cutting insert 14 from the tool holder 12.

[0066] The tool holder 12 further comprises in its interior a coolant channel 36, which can be seen particularly in FIGS. 3-5. This coolant channel 36 serves for guiding coolant or lubricant, which is usually subjected to a high pressure and is sprayed into the region of the cutting insert 14, i.e. into the region 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 at the upper clamping jaw 20, to thereby direct coolant onto the cutting insert 14, preferably from obliquely above.

[0067] In the present embodiment, the coolant channel 36 comprises a further coolant outlet opening 42, which is referred to herein as second coolant outlet opening 42. However, this second coolant outlet opening 42 is only an optional feature of the tool 10. The second coolant outlet opening 42 is arranged below the cutting insert receptacle 18. More specifically, in the present embodiment, the second coolant outlet opening 42 is arranged on a forwardly projecting protrusion of a so-called support 44, which is adjacent to a lower end of the lower clamping jaw 22 and supports or mechanically stabilizes the lower clamping jaw 22. Inside the tool holder 12, the coolant channel 36 branches at a branch point 46 into a first sub-channel 48, which opens into the coolant outlet opening 40, and a second sub-channel 50, which opens into the second coolant outlet opening 42. However, as mentioned above, the second sub-channel 50 and the second coolant outlet opening 42 may in principle be omitted without departing from the spirit and scope of the present disclosure. Therefore, In the following, mainly the embodiment of the first sub-channel 48 of the coolant channel 36 is discussed in more detail.

[0068] The coolant channel 36, in particular its first sub-channel 48, meanders through the interior of the tool holder 12 (see in particular FIGS. 3-5). It runs around the bores 16 as well as around the clamping screw 30. The coolant channel 36 is therefore configured to be bent at several points. Particularly preferably, the coolant channel 36 has a continuously changing curvature along its course. Hence, it has preferably no sharp corners, sharp or step-like shoulders. This is particularly advantageous from a fluid-dynamic point of view, as it allows undesirable turbulent flows within the coolant channel 36 to be avoided or at least reduced to a minimum.

[0069] The coolant channel 36, in particular its first sub-channel 38, comprises a plurality of portions, which are referred to herein as initial portion 52, middle portion 54, and end portion 56.

[0070] The initial portion 52 forms the first portion of the coolant channel 36, or the first channel part 48 thereof. It is adjacent to the coolant inlet opening 38 and extends along a majority of the length of the coolant channel 36. In this initial portion 52, the coolant channel 36 preferably has a circular cross-section.

[0071] The end portion 56 forms the other end of the first sub-channel 48 of the coolant channel 36. The end portion 56 is arranged in the upper clamping jaw 20 and opens into the coolant outlet opening 40. The end portion 56 of the coolant channel 36 as well as the coolant outlet opening 40 each have an elongated cross-section, the width of which is less than its height measured orthogonally thereto.

[0072] The middle portion 54 of the coolant channel 36 forms the transition between the initial portion 52 and the end portion 56. Thus, a first end of the middle portion 54 adjoins the initial portion 52 and a second, opposite end of the middle portion 54 adjoins the end portion 56. Like the initial portion 52, the middle portion 54 is preferably arranged within the base body of the tool holder 12, i.e. not within the upper clamping jaw 20. Preferably, only the end portion 56 is arranged inside the upper clamping jaw 20. The transition between the middle portion 54 and the end portion 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.

[0073] The coolant outlet opening 40, which is arranged at the upper clamping jaw 20, is configured as an elongated opening whose width b.sub.1 is smaller than its height h.sub.1 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. However, in the present embodiment, the oval coolant outlet opening 40 comprises two parallel flanks 58 and two arcuate sections 60 connected to opposite ends of the straight flanks 58. The arcuate sections 60 may be shaped as semicircles or as half-ellipses. Preferably, the straight flanks 58 each merge into the arcuate sections 60 in a continuous progression.

[0074] The end portion 56 of the coolant channel 36 adjoining the coolant outlet 40 is also elongated. The end portion 56 extends longitudinally along a channel center axis 62, which extends in the middle or centrally along the end portion 56 (see in particular FIG. 1). The end portion 56 has an elongated cross-section particularly with respect to this channel center axis 62. More specifically, a width b.sub.2 of the end portion 56 measured orthogonally to the channel center axis 62 is less than a height h.sub.2 of the end portion 56 measured orthogonally to the channel center axis 62 and orthogonally to the width b.sub.2 (see particularly FIGS. 4 and 6).

[0075] Thus, not only the coolant outlet opening 40 but also the end portion 56 has an elongated, preferably oval shape. The coolant jet is therefore fanned out in the direction of or parallel to the height h.sub.1 and h.sub.2 and laterally focused along the width b.sub.1 and b.sub.2. This is particularly advantageous for tools with comparatively narrow upper clamping jaws 20, which are used for machining grooves with comparatively small groove widths. Also in such a case, even when machining small groove widths, a sufficiently large coolant flow can be guaranteed, which can be optimally used for cooling and lubricating the usually narrowly designed machining area.

[0076] The channel center axis 62 of the end portion 56 is preferably oriented at an acute angle to the longitudinal axis 34 of the tool holder 12. In addition, the front face of the upper clamping jaw 20 is preferably beveled so that the coolant outlet opening 40 arranged on this front face of the upper clamping jaw 20 is also oriented at an acute angle to the longitudinal axis 34 of the tool holder 12. The jet of coolant emerging from the coolant outlet opening 40 thus impinges on the cutting insert 14 from obliquely above.

[0077] Preferably, the height h.sub.1 of the end portion 56 increases along the channel center axis 62 towards the coolant outlet opening 40 (see FIG. 6). The increase in height h.sub.2 preferably occurs continuously along the channel center axis 62. This advantageously contributes to the aforementioned fanning out of the coolant jet.

[0078] As can be seen from FIG. 4, the width b.sub.2 is preferably constant along the channel center axis 62 in the end portion 56.

[0079] The middle portion 54 of the coolant channel 36 has a somewhat more complex configuration in the present embodiment. In this middle portion 54, the coolant channel 36 transitions from its initially circular cross-section in the initial portion 52 to the described elongated or oval cross-section in the end portion 56. Preferably, the diameter d of the circular cross-section of the coolant channel 36 in the initial portion 52 is larger than the width b.sub.2 of the end portion 56, but smaller than the height h.sub.2 of the end portion 56. Accordingly, the cross-section of the coolant channel 36 in the middle portion 54 decreases in width, but increases in height. However, an increase in height is not necessarily required, since the height h.sub.2 of the end portion 56 at the transition to the middle portion 54 can also be the same as the diameter d of the initial portion 52. In such a case, the coolant channel 36 in its middle portion 54 would therefore only be reduced in width, but not in height. This is possible because the height h.sub.2 of the coolant channel 36 in the end portion 56 preferably increases towards the coolant outlet opening 40, as already mentioned.

[0080] Such a relatively complex shaped coolant channel 36, as previously described, can be most easily and cost-effectively manufactured by additive manufacturing of the tool holder 12. The tool holder 12 is preferably manufactured in its entirety by means of additive manufacturing.

[0081] Finally, it should be mentioned that the above-described division of the coolant channel 36 into initial portion 52, middle portion 54 and end portion 56 is not absolutely necessary. Particularly in case of a configuration of the tool holder 12 with an overall small width, for example in the case of a configuration of the tool holder 12 as a parting blade, the coolant channel 36 can also be configured with an overall elongated or oval cross-section. In such a case, a transition between the circular cross-section and the oval or elongated cross-section, as described above for the middle portion 54, can be dispensed with. Thus, the coolant channel 36 could then also be formed with a constant cross-section (elongated or oval) that is unchanged along the course of the channel. In principle, the coolant channel 36 can also be formed with a constant cross-section in its end portion 56 without its height h.sub.2 increasing in the direction towards the coolant outlet opening 40. Further variations, in particular with respect to the shape of the tool holder 12, are also possible without leaving the spirit and scope of the present disclosure. Additive manufacturing of the tool holder 12 is preferred, but not absolutely necessary.

[0082] It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

[0083] As used in this specification and claims, the terms “for example,” “e.g.,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.