EP3595835A1

EP3595835A1 - Tool body and a method for the production thereof

Info

Publication number: EP3595835A1
Application number: EP18710041.7A
Authority: EP
Inventors: Roland Barbist; Robert BIERBAUMER; Alexander AMBOS; Johannes Mayr; Oliver Rapp
Original assignee: Ceratizit Balzheim & Co KG GmbH; Guenther Wirth Hartmetallwerkzeuge & Co KG GmbH
Current assignee: CERATIZIT BALZHEIM GMBH & CO. KG; Ceratizit Austria GmbH
Priority date: 2017-03-14
Filing date: 2018-03-08
Publication date: 2020-01-22
Also published as: AT16076U1; WO2018166889A1

Abstract

The invention relates to a tool body (1) for a rotating tool, in particular a drill or end milling cutter, comprising along the longitudinal axis (L) thereof: an outlet section (2), which has, at least in sections, spiral-shaped internal cooling channels (3); a supply section (4) having at least one central recess (5) extending substantially straight and parallel to the longitudinal axis (L); a joining zone (6), by way of which the outlet section (2) and the supply section (4) are connected to one another, wherein a transfer area (7) is formed, in which by way of at least one transfer cavity (81), the central recess (5) is connected to the cooling channels (3) of the outlet section (2) in a communicating manner. The invention is characterized in that in the joining zone (6), the outlet section (2) and the supply section (4) are connected to one another by way of a sinter joining, wherein the joining zone (6) extends along a cross-section of the tool body (1) and transversely to the longitudinal axis (L). The invention further relates to a method for producing a tool body.

Description

Tool body and a method of manufacture

The invention relates to a tool body, and a method for

Production of the same.

In the production of rotating tools, for example drills or milling cutters, it is known to produce rod-shaped base bodies by extrusion molding (extruding) a plasticized powder mass and then to sinter them. Alternative manufacturing methods for producing the main body are a direct pressing and molding. Shapes here are understood to mean an abrasive working of a green body.

The sintered base body is referred to as a blank or bar blank.

After sintering, cutting and flutes are introduced into the blank by grinding. The processed blank forms the tool.

As a rule, such tools are made entirely from a hard material, in particular hard metal. In the latter case one speaks of

Solid carbide tools. Alternative hard materials are cermets or ceramics. Also known are solutions in which a hard material in only one

cutting area of the tool is applied.

Furthermore, it is known to introduce internal channels into the main body for the transport of coolant or lubricant.

DE10202954A1 shows a rod-shaped drill made of hard metal or ceramic with at least one extending in the longitudinal direction

Inner recess through which coolant or lubricant can be brought into a cutting region of the drill.

For the production it is described that first in a first

Process step is made of a plastic mass existing rod-shaped body with at least one rectilinear inner recess. In the next step, the extruded rod is subjected to a rolling motion, so that the body is twisted uniformly. After this

Twisting lies within the body helical or spiral

extending inner recess in front. DE29624253U1 shows a method for the production of bars from a plastic raw material, such as a powder metallurgical or ceramic mass, wherein via flow guides in

Extrusion tool in rod-shaped tool body internal channels variable spiral pitch are introduced.

DE10142265A1 shows a rod-shaped tool with wire

internal cooling channels, wherein a shank region of the tool has a center recess extending in the direction of the rod center axis. The central recess and the internal cooling channels are communicatively connected with each other. A twisting of the rod can occur during or after the extrusion. The central recess is preferably introduced into the dimensionally stable, not yet sintered blank. The

Center recess may e.g. be designed as a bore.

DE3709647 shows a drilling tool with internal cooling channels, in which a cutting part is soldered onto a carrier part. A disadvantage of the known from the prior art solutions is that the transport of a fluid (such as a coolant or lubricant) is carried flow-unfavorable and / or low degrees of freedom

Tool grinding exist.

Extend the possibly. Driven coolant channels over the entire rod or tool length, usually the very small diameter of the

Coolant channels together with the enlarged by the twist

unwound length high friction losses from a supply of the fluid at a clamping or shank portion of the tool to

Outlet openings in a cutting portion of the tool.

With regard to the friction losses it is better if the

Coolant channels do not extend over the entire rod or tool length, but a Mittenausnehmung is provided in a clamping or shank portion of the tool for feeding the coolant channels. However, here the degrees of freedom in the tool grinding are limited. Another disadvantage of the previously known production process is the high production costs.

Object of the present invention is therefore to provide a tool body or a tool with improved properties and a method for

Specify the production thereof.

A tool body according to the invention comprises:

an outlet portion having, at least in sections, spirally extending internal cooling channels, and

a supply section with at least one central recess extending substantially straight and parallel to the longitudinal axis, a joining zone over which the exit section and the

Supply section are interconnected,

wherein a transfer region is formed, in which the central recess via at least one transfer cavity with the cooling channels of the

The outlet section is communicatively connected, wherein the outlet section and the supply section are connected to each other in the joining zone via a Sinterfügung, wherein the joining zone along a

Extending cross-section of the tool body and transverse to the longitudinal axis.

The term "tool body" includes both a blank and a machined tool.

The blank are still no cutting or flutes introduced.

In the machined tool are - usually by grinding - cutting and flutes introduced. As a blank so the finished sintered

Tool body designated without tool grinding.

Sintering is understood to be a compound that is characterized by a

Intermediate sintering of powder metallurgy produced components arises. An advantage of a Sinterfügung is that in the joining zone of the

sintered body usually no filler material is present. As a result, a high strength and temperature resistance of the joining zone is achieved. The tool body has, compared to eg a soldering superior mechanical Properties, but allowed in terms of the design of the

internal cooling ducts have great flexibility, as they are made in one piece over a conventional manufacturing process

Tool body would not be displayed.

The terms "exit section", "service section" and

"Transfer area" are selected in relation to the predominant function of the respective section for guiding a coolant and / or lubricant.Cooling and / or lubricant is conducted into and into the tool body via the supply section Lubricant from the supply section to the cooling channels of the

Passed out exit section. On a working side front side of the

Outlet section may leak the coolant and / or lubricant.

The exit section is provided as a cutting part of a later tool, while the supply section inter alia to

Clamping the tool is used. The supply section can likewise have chip spaces at least in sections, which serve primarily to remove chips. However, cutting sections may also be provided on the supply section.

Preferably, the joining zone is formed blunt. Stump means im

In the context of the present application, the cross-sectional areas of the joined sections are substantially planar. An elaborate processing for producing a toothing or the like is eliminated.

Particularly preferably, the joining zone is flat and normal to the longitudinal axis of the tool body. It can be provided that the transfer cavity having

Transition area

completely in the exit section or

completely in the supply section or overlapping in the outlet section and in the supply section is formed.

It can be provided that the transfer cavity is designed in the form of obliquely to the longitudinal axis and substantially rectilinear transfer channels. Such substantially rectilinear transfer channels ensure a particularly streamlined transfer of coolant or lubricant from the central recess to the cooling channels. The

Transfer channels can be introduced, for example, through bores at the exit section or at the supply section or overlapping at the exit section and at the supply section. They are untwisted and generally run obliquely to the longitudinal axis, since the cooling channels are preferably radially further out than the center recess. Alternatively, it can be provided that the transfer cavity in the form of a

Distribution chamber is formed. For this purpose - for example by milling - a pocket is introduced into that end face of the supply section, which is connected to the outlet section. The distribution chamber could also in the exit section or overlapping in the exit section and in the

Be formed supply section. The distribution chamber is like that

dimensioned that the radially outer cooling channels in the

Distributor chamber and so from the middle recess of the

Supply section can be fed. In other words, the distribution chamber is a radial expansion of the central recess such that a fluid connection to the cooling channels is produced. The advantage of the distribution chamber as a transfer cavity is the ease of manufacture. A disadvantage is the cross-sectional weakening in the region of the distribution chamber.

It is preferably provided that at the outlet section a primary

Cutting section is formed with at least two spirally extending flutes and spiral webs, wherein the inner cooling channels extend in the spiral webs. This describes the case that the tool body is machined into a tool. The flutes and spiral webs are usually introduced by grinding.

The spiral webs are those areas that remain between the flutes. The internal cooling channels run in the spiral webs. The spiral webs have a substantially same spiral pitch we the

Cooling channels on. This has the advantage that the cutting section

can be reground without the risk that

grind internal cooling channels and thereby make the tool unusable.

It is favorable if the flutes have a helix angle of 15 ° to 30 °. The spiral angle of the flutes is defined by the inclination of a tangent to a spiral web with respect to the longitudinal axis of the tool body.

It can be provided that a secondary cutting section is formed at the supply section, which has at least one chip space extending along the longitudinal axis.

The at least one chip space can be formed in the form of a spirally running flute. There may be several chip spaces. It is preferred that the flutes of the primary cutting section merge into the chip spaces of the secondary cutting section. Thus, the number of chip spaces of the supply section corresponds to the number of flutes of the exit section.

This allows a removal of chips from the exit section. The secondary cutting section can also be designed to be cutting.

It is preferably provided that the secondary cutting section extends over a length greater than 20% of the supply section, preferably over a length greater than 40% of the supply section.

By forming the secondary cutting section over a substantial portion of the supply section, the supply section is advantageously used for the removal of chips from the outlet section or optionally also for cutting. It can be provided that the central recess of the

Supply section in that region of the supply section on which the secondary cutting portion is formed, a smaller

Has diameter than in that area supply section on which no chip space is formed. This can be advantageous for mechanical reasons, since the formation of chip spaces at the service section reduces its load-bearing cross-section. By providing a smaller diameter of the center cutout in this area, more load-bearing cross section remains available for the transmission of forces and moments. Also, the larger diameter at a remote end of the supply section facilitates entry of coolant / lubricant and reduces flow losses. It is preferably provided that the at least one chip space of the secondary cutting section one of the flutes of the primary

Cutting section has different depth and / or a different spiral angle.

This expresses the fact that the course and the form of the

Chip spaces of the secondary cutting section of the course and the

Form of the flutes of the primary cutting section may differ. For example, the chip spaces can be steeper (have a smaller spiral angle) and / or be less pronounced than the

Flutes of the primary cutting section. For example, the chip spaces can also be wider than the flutes in order to facilitate the removal of chips.

Since a central recess is formed in the supply section and no spiral-running cooling channels, one is free in the choice of the spiral angle of the chip spaces of the secondary cutting section (no risk of opening a cooling channel by grinding).

Preferably, the at least one chip space of the secondary

Cutting section on a spiral angle between 0 ° and 30 °. This choice causes a particularly favorable removal of chips. It is favorable when the spiral angle of the secondary cutting portion is smaller than the spiral angle of the primary cutting portion, because the distance along the chip spaces is shorter and the chip removal is facilitated.

Particularly preferably, the helix angle of the chip space of the secondary cutting section changes along its length. Thus, at the transition to the primary cutting section at the secondary cutting section, the same spiral angle may still be present as in the primary cutting section, in order then to decrease in the direction of a clamping section. It is also conceivable that the chip spaces of the secondary cutting section close to the clamping section are parallel to the longitudinal axis, i. one

Have spiral angles of zero.

It can be provided that the outlet section and the

Supply section made of hard material of different hard material composition. Thus, the different requirements for the outlet section and the supply section can be taken into account.

The primary cutting section provided at the exit section primarily undertakes the cutting work, while the service section serves primarily for the transmission of forces and for clamping. Therefore, it has been found to be particularly advantageous, the outlet section and the

Supply section of hard materials of different hard material composition form. In the context of the present application, "hard material" is understood as meaning materials of high hardness, suitable for the production of a cutting tool, such as, for example, ceramics, cermets or hard metals Preferably, the tool body is formed from a hard metal, ie tungsten carbide and a binder, usually cobalt.

Particularly preferably, the outlet section is formed from a hard material composition of higher hardness than that of the supply section. As standing in a cutting engagement with a material to be machined, a higher hardness in the primary cutting section is favorable. Of the Supply section preferably has a lower hardness / higher toughness.

It can be provided that the hard metal composition of

Supply section contains recycled carbide. So can the

Supply section may be made of a cheaper carbide grade.

It can be provided that the hard material contains a binder and the hard material of the supply section has a binder composition deviating from the hard material of the outlet section and / or a binder content deviating from the hard material of the outlet section. This applies in particular to hard metal, whose mechanical properties can be varied within wide limits via adaptation of binder composition and / or binder content.

For example, the supply section could be made of a carbide grade with a higher binder content (for example 15% Co) and the

Outlet portion of a carbide grade with low binder content (for example, 10% Co) be formed. With otherwise unchanged parameters, a higher binder content leads to lower hardness and higher toughness.

It is preferably provided that the ratio of the length of

Supply section to the length of the outlet section greater than 1, 5, preferably greater than 3, more preferably greater than 5.

This expresses that the supply section of the

Tool body is significantly longer than the exit section.

The exit section, in which internal cooling passages run in a spiral, can be kept short. Thus, that part of the

Tool body, in which a spiral angle of flutes by a

Spiral angle of internal cooling channels is given, especially short. Thus, there is a simple and cheap way for the tool body, variable spiral angle of flutes or chip spaces along the

To realize longitudinal extension of the tool body. Complex solutions, such as a variation of the helix angle of internal cooling channels, can be dispensed with.

In particular, the Sinterfügung allows to form the joining zone in a region of the tool body, which is exposed in use high thermal and mechanical loads. A solder joint would have to be far away from a work area because of limited thermal capacity.

It is preferably provided that a pitch circle diameter, which circumscribes the inner cooling channels of the outlet section, is larger than a diameter of the center cutout of the feed section in FIG

Transition area.

Seen in a cross section, so are the cooling channels of the

Outlet section further outward than the center recess of the

Supply section. This is advantageous because then the outlet openings of the inner cooling channels at the working end of the outlet portion are low for a supply of coolant or lubricant. The transfer cavity thus connects the radially outer cooling channels with the more centrally located center recess.

The buzzer preferably corresponds to the cross-sectional areas of the cooling channels of the cross-sectional area of the central recess.

The supply section preferably has a clamping section on which no chip spaces are formed.

The use of the tool body is preferred as a solid carbide drill or as a solid carbide milling cutter.

Protection is also sought after for a process of making a

Tool body with the steps:

Providing a spirally extending inside cooling channels having outlet portion, Providing a supply section with at least one in

Substantially straight and parallel to a longitudinal axis of the

Supply section extending center recess,

Forming at least one transfer cavity at a front end of the exit section and / or the supply section,

Sintering the exit portion with the supply portion to the tool body so that the transfer cavity is the inner one

Cooling channels of the outlet portion communicates with the central recess of the supply section communicates.

The provision of the outlet section or of the supply section can take place, for example, by means of extrusion molding and subsequent sintering. The sections may be completely sintered (i.e., final density) or presintered.

Preferably, the supply section and the cutting section are sintered prior to sintering or at least pre-sintered. The tool body is thus produced by sintering together already sintered or at least pre-sintered sections.

The formation of the at least one transfer cavity is preferably done prior to sintering or presintering, i. in the green state or pre-sintered state.

It is preferably provided that the transfer cavity in the form of obliquely to the longitudinal axis and substantially rectilinear transfer channels is formed such that the transfer channels - based on a cross-sectional area of the outlet portion and the supply portion - of a pitch circle diameter, which circumscribes the inner cooling channels of the outlet portion , towards the diameter of the

Center recess of the supply section extend.

It can be provided that the transfer cavity in the form of a

Distribution chamber is formed cylindrical and / or frusto-conical shape whose diameter on the cooling channels facing side at least the pitch circle diameter, which the inner Cooling channels of the outlet section circumscribes corresponds. Compared to the variant with transfer channels a distribution chamber causes a reduction of the supporting cross section and is therefore not always favorable for mechanical reasons.

It is preferably provided that the supply section is formed from a different hard material composition than the outlet section.

To form the tool body as a tool, such as drilling tool or milling tool are in the outlet section and, if necessary. Also in the

Supply section flutes and cutting introduced, usually by grinding.

A subdivision of the tool body into a supply section and an exit section allows a nearly independent one another

Optimization of the external geometry and internal cooling.

In summary, a number of advantages can be achieved by the invention:

- Spiral pitches of flutes in primary cutting section and

secondary cutting section are decoupled.

- The streamlined design of the transfer of coolant from the central recess in the cooling channels causes improved cooling performance and reduced flow losses.

- The two-part design of the tool body allows the combination of different hard materials, especially carbide grades, for

Exit section and service section.

- Regrinding is also possible process-reliable, if the primary cutting section and the secondary cutting section with respect to the spiral pitches differ. The invention is explained in more detail below by figures. 1 shows a view of a tool body according to a first

embodiment

Fig. 2 is a view of a tool body according to a second

embodiment

Fig. 3 shows an embodiment with a tool body as

drilling

Fig. 4 shows an embodiment with a tool body as

milling tool

Fig. 5a to 5h details of the design of the cooling channels and the

Übergabekavität

Fig. 6 to 14 further embodiments

FIG. 1 shows a perspective view of a tool body 1 according to a first exemplary embodiment.

The tool body 1 is designed here as a finished tool. As mentioned at the beginning, the term "tool body" encompasses both a blank and a machined tool In the case of a blank, no flutes and cutting edges are yet introduced.

The tool body 1 has a longitudinal axis L along which

different sections of the tool body 1 are to be distinguished.

The tool body 1 comprises an outlet section 2 with a length a, which is connected via a joining zone 6 to a supply section 4 of a length c. The joining zone 6 is formed as Sinterfügung. As a result, no additional materials are present in the joining zone 6. The outlet section 2 and the supply section 4 are butt-connected. The joining zone 6 is preferably flat. This allows a favorable production with high strength of the joining zone 6. Such a trained tool body 1 is in terms of its mechanical properties equivalent to one monolithic tool body; the joining zone 6 is not

Weakening the composite.

The supply section 4 has a substantially straight, cylindrical and parallel to the longitudinal axis L extending center recess 5.

In a chucking section 12 of the supply section 4, the

Tool body 1 are fixed in a clamping, not shown here. About the center recess 5 can be supplied to the clamping cooling medium.

Spiral grooves 9, spiral webs 10 and cutting edges 14 are formed at the exit section 2, whereby a primary cutting section 21 is created. In the spiral webs 10 of the outlet section 2 extend internal cooling channels 3, which emerge on a working side end face 13 of the tool body 1. "Working" refers to the direction along the longitudinal axis L, which points in use to a workpiece to be machined. In contrast, the clamping portion 12 is located at the remote end of the tool body. 1

The cooling channels 3 have a substantially same spiral pitch as the spiral grooves 9 or the spiral webs 10 of the primary cutting section 21. This allows regrinding, without the risk of grinding the cooling channels 3 and thus open.

The internal cooling channels 3 can also be different

Diameters and / or different radial position to be formed. It is conceivable, for example, to provide two spiral channels 3 extending in a spiral manner parallel to one another in a spiral web 10.

In the present exemplary embodiment, a secondary cutting section 22 is formed on the supply section 4.

The secondary cutting portion 22 has chip spaces 1 1, which extend spirally along the longitudinal axis L. The chip spaces 1 1 continue from the spiral grooves 9 of the primary cutting section 21. In this example, they show a smaller spiral angle than the spiral grooves 9 or the spiral webs 10 of the primary cutting section 21. Of the

Tool body 1 thus has different spiral angles of the grooves 9, 1 1. Nevertheless, the tool body 1 remains easy nachschleifbar, as in the webs of the secondary cutting section 22, there are no spiraling cooling passages.

In this example, the spiral angle of the chip spaces 1 1 over the length of the secondary cutting portion 22 is constant. It may alternatively be provided that the spiral angle of the chip space 1 1 of the secondary

Cutting section 22 changed over the length thereof. Thus, at the transition to the primary cutting section 21 on the secondary cutting section 22, the same spiral angle may still be present as in the primary cutting section 21 in order to then decrease in the direction of the clamping section 12. It is also conceivable that the chip spaces 11 run close to the clamping section 12 almost parallel to the longitudinal axis L, i. have a spiral angle of zero. The chip spaces 1 1 of the secondary cutting portion 22 serve

primarily a removal of chips from the primary

Cutting section 2. A small spiral angle is favorable for a removal of chips.

In the present embodiment, the secondary extends

Cutting portion 22 over more than 50% of the supply section 4. Thus, a significant portion of the supply section 4 is shared for a removal of chips from the primary cutting portion 21. Subsequently to the secondary cutting section 22, the clamping section 12, which is free of chip spaces 11, is formed on the supply section 4.

In the present embodiment, the center recess 5 of the supply portion 4 in the region of the supply portion 4, on which the secondary cutting portion 22 is formed, a smaller diameter than in that region supply portion 4, on which no chip space 1 l is formed, i. as in the clamping section 12.

This may be advantageous for mechanical reasons, since the formation of chip spaces 1 1 on the supply section 4 reduces its load-bearing cross-section. Alternatively it can be provided that the tool body 1 has no secondary cutting portion 22. In this case, only the primary cutting portion 21 is grooved. In a transition region 7, the cooling channels 3 via substantially rectilinear and oblique transfer channels 81 with the

Center recess 5 connected. In this way, the cooling channels 3 can be supplied via the center recess 5 with coolant or lubricant. It can be seen that the cut surfaces of the transfer channels 81 with the

Cooling channels 3 radially (ie with respect to a radial direction R of the

In other words, a pitch circle diameter which circumscribes the inner cooling channels 3 of the outlet section 2 is greater than the diameter of the central recess 5 of the

Supply section 4 in the transition area 7.

This, starting from the central recess 5 radially outward-pointing course of the transfer channels 81 allows that the cooling channels 3 can be located radially further outside than the central recess 5. This is advantageous because then outlet openings of the inner cooling channels 3 of the primary

Cutting section 21 are favorable for a supply of coolant or lubricant to the working side end face 13.

In the present exemplary embodiment, the transition region 7 having the transfer channels 81 lies completely in the supply section 4. In alternative embodiments, the transitional region 7 may also be completely in the outlet section 2 or overlapping in the exit section 2 and in the

Supply section 4 may be formed.

If the transfer channels 81 are formed in the exit section 2, this has the advantage that a joining of the exit section 2 and the supply section 4 is angle-invariant. This means that it is not necessary to pay attention to their angular position when joining the outlet section 2 and the supply section 4. If the transfer ducts 81 are formed in the supply section 4, a correct angular position of the sections relative to each other must be taken into account during the joining, so that the respective outlets of the cooling ducts 3 and Transfer channels 81 are superimposed. The transfer channels 81 are formed here in the supply section 4.

An introduction of the transfer channels 81 is preferably via a

Greenware processing, i. before sintering the relevant section.

The outlet section 2 is relatively short in relation to the total length of the tool body 1. In the present embodiment, the proportion of the outlet section 2 is about 16% of the total length of the tool body. 1 In other words, here is the ratio of the length c of

Supply section 4 to the length a of the outlet section 2 greater than five, (c / a)> 5.

The supply section 4 consists of a first

Hard material composition, for example from a first

Carbide composition. The outlet section 2 consists of a second hard metal composition. This makes it possible to use a suitable material for the respective mechanical and / or thermal requirements. For example, for the supply section 4, a hard metal type of high toughness can be used, while for the exit section 2 a hard metal type of high hardness is used. A cheaper carbide grade could also be used for the supply section 4, since the mechanical requirements are generally lower than those for the outlet section 2.

FIG. 2 shows a tool body 1 in a further exemplary embodiment. Here, the tool body 1 is designed as a blank, i. There are no cutting or flutes formed. The outlet section 2 and the supply section 4 are butt-joined in the joining zone 6 by a sintering connection. As a result, in the joining zone 6 no

Additional materials available. In the transition region 7, the wired cooling channels 3 of the outlet section 2 via transfer channels 81 with the

Center recess 5 connected. The transfer channels 81 are in

Supply section 4 is formed. The aspect ratios of exit section 2 to supply section 4 are selected as in FIG.

From the blank according to FIG. 2, a drilling or milling tool can be produced, for example, by inserting flutes and cutting edges.

Figure 3 shows an embodiment in which the tool body 1 is formed as a finished machined drilling tool.

At the working end face 13 is an outlet opening of a

inside wiring cooling channel 3 to recognize. The tool body 1 has a supply section 4 and an exit section 2. At the

Outlet section 2 is a primary cutting portion 21 with flutes 9 and spiral webs 10 is formed.

Furthermore, there is a secondary cutting portion 22 which is formed cutting in the present case. The secondary cutting portion 22 does not differ externally from the primary cutting portion 21. 1m

Inside the tool body 1, a joining zone 6 is formed between the outlet section 2 and the supply section 4, via which the

Outlet section 2 and the supply section 4 are connected to each other via a Sinterfügung. In the interior of the outlet section 2, wired cooling channels 3 extend along the spiral webs 10.

The joining zone 6 is located in the present example about 3.5 x D from the working end 13, with D is diameter.

At the supply section 4, an ungrouted clamping section 12 is formed, which serves for clamping the drilling tool.

The spiral angle of the primary cutting portion 21, θι, between a tangent to a spiral web 10 and the longitudinal axis L of the tool body 1 is determined. It is in the present case 30 °.

The spiral angle of the secondary cutting portion 22, θ ₂ , is determined between a tangent to a ridge of the secondary cutting portion 22 and the longitudinal axis L of the tool body 1. It is also about 30 ° in the present case. Preferably, the spiral angle of the secondary

Cutting portion 22, θ ₂ , smaller than the spiral angle θι the primary cutting portion 21st Particularly preferred is the case in which the secondary cutting portion 22 has a variable over the length of the secondary cutting portion 22 spiral angle θ ₂ .

Figure 4 shows an embodiment in which the tool body 1 is formed as a finished machined milling tool. The tool body 1 has a supply section 4 and an outlet section 2, which are connected to one another in the joining zone 6 via a sintering connection. At the exit section 2, a primary cutting section 21 with flutes 9 and spiral webs 10 is formed.

The joining zone 6 is located in the present example about 1 x D from the working side end 1 3, with D is the diameter of the tool.

At the supply section 4, a clamping section 12 is formed, which serves for clamping the drilling tool. In the interior of the outlet section 2 run wired cooling channels 3 (not visible here) along the spiral webs 10th

FIGS. 5a to 5h show variants of the design of cooling channels 3 and transfer cavities 8, 81, 82.

Shown are in each case a simplified plan view of the working end 13 of the tool body 1 and each including a simplified cross section through the tool body. 1 Of course, the representation of the wired cooling ducts 3 is not correct geometrically - rather, due to the corrugated form, the twisting of the cooling ducts 3 should be symbolized. Reference numerals are given in FIG. 5a; complete entry of reference symbols in the following figures was dispensed with because of the repetitions.

In FIG. 5a, the transfer channels 81 connect the central recess 5 with the wired cooling channels 3 in such a way that between the junction of the

Transfer channels 81 in the cooling channels 3 and the joining zone 6, the cooling channels 3 run blind. The transfer channels 81 are introduced here into the exit section 2. The joining of exit section 2 and supply section 4 is then angularly invariant.

It can also be seen from FIG. 5a that a pitch circle diameter Di "circumscribing the internal cooling passages 3 of the outlet section 2 becomes larger is as a diameter DP "of the central recess 5 of the

Supply section 4 in the transfer area 7. Between the junction of the transfer channels 81 in the cooling channels 3 and the joining zone 6, the cooling channels 3 run blind. In FIG. 5b, the transfer channels 81 connect the central recess 5 with the wired cooling channels 3 so that the junction of the transfer channels 81 lies in the cooling channels 3 in the joining zone 6. The transfer channels 81 are introduced here into the supply section 4. The central recess 5 is closed from the junction of the transfer channels 81 up to the joining zone 6 or not formed from the outset over the entire length of the supply section 4. When joining exit section 2 and supply section 4, attention must be paid to the correct angular position relative to each other.

In FIG. 5c, the transfer channels 81 connect the central recess 5 with the wired cooling channels 3 so that the junction of the transfer channels 81 lies in the cooling channels 3 in the joining zone 6. The transfer channels 81 are introduced here into the supply section 4. The central recess 5 runs blind in the joining zone 6.

In FIG. 5 d, the transfer cavity is designed as a distributor chamber 82. The distribution chamber 82 is a pocket at the working end of the

Supply section 4 introduced. The distribution chamber 82 is a

Enlargement of the open cross-section of the central recess 5 on the pitch circle diameter of the cooling channels 3 and supplies in this way the cooling channels 3. As can be seen from the figure, the formation of the

Distribution chamber 82 to a weakening of the supporting cross section of the tool body. 1 On the other hand, a distribution chamber 82

production technology very easy to implement.

In the exemplary embodiments of FIGS. 5a to 5d, two are each

Cooling channels 3 formed.

In a departure therefrom, FIGS. 5e to 5h show variants with more than two cooling channels 3.

Figure 5e shows an embodiment with three cooling channels 3. The three

Cooling channels 3 are on the same pitch diameter Di «, as in the Top view of the working end 13 is illustrated. Analogous to the example of FIG. 5a, the transfer channels 81 are in the exit section 2

introduced and terminate blind in the joining zone 6. The cooling channels 3 are distributed here along a pitch circle Di «at equal angular intervals. Figure 5f shows an embodiment with four cooling channels 3. The cooling channels 3 are here along a pitch circle Di «at unequal angular intervals α, ß distributed. The connection of the cooling channels 3 with the central recess 5 takes place here by transfer channels 81, which are formed in the outlet section 2.

Figure 5g shows an embodiment with four cooling channels 3, which are formed at different pitch circles Di «1 and Di« 2. The connection of the cooling channels 3 with the central recess 5 takes place here by transfer channels 81, which are formed in the outlet section 2.

FIG. 5 h shows an exemplary embodiment according to which two radially outer cooling channels 3 extend from the outlet section 2 via the

Supply section 4 extend therethrough. Further inside, there are two further cooling channels 3, which are formed exclusively in the outlet section 2. These further internal cooling channels 3 are connected by transfer channels 81 with the central recess 5. This arrangement can be used, for example, to supply different media. For example, a cooling medium can be supplied via the further outward cooling channels and a lubricating medium can be supplied via the further inner cooling channels.

Thus, in FIGS. 5a to 5h, variants with regard to the position of the joining zone 6, the number and position of the cooling channels 3 and the configuration and position of the transfer cavity are shown. The request for protection is not limited to the variants shown. There are other modifications of the

Embodiments and combinations thereof possible.

Figure 6 shows an embodiment of a tool body 1 in a representation as a so-called wire model with 2 cooling channels 3, which are connected via two transfer channels 81 with the central recess 5. The

Mittenausnehmung 5 has on the remote from the work (the side facing away from the working end 13) side a larger diameter than in the area of Branch of the transfer channels 81. Thus, friction losses in the central recess 5 can be further reduced.

The transfer channels 81 are introduced here in the supply section 4. When joining outlet section 2 and supply section 4 in the

Join zone 6 must be paid to a correct angular position of the outlet section 2 and supply section 4 to each other.

FIG. 7 is analogous to FIG. 6 with the difference that the central recess 5 has a constant diameter over the entire length of the

Supply section 4 has.

Figure 8 shows a detail of the penetration of cooling channels 3 with the

Transfer channels 81. The transfer channels 81 are in the

Outlet section 2 is formed. This has over an embodiment of the transfer channels 81 in the supply section 4 has the advantage that the

Positioning of exit section 2 and supply section 4 is angularly invariant at the junction. In the joining zone 6, the transfer channels 81 open onto the diameter of the inner recess 5, so that outlet section 2 and supply section 4 can be added as desired with respect to their angular position. If the transfer channels 81, however, executed in the supply section 4, it must be in the addition to a correct angular position of

Outlet section 2 and supply section 4 are respected each other.

FIG. 9 shows a variant with three cooling channels 3 and a center cut-out 5 with an enlarged diameter on the side remote from the working side

Supply section 4. The transfer channels 81 are in

Supply section 4 is formed.

FIG. 10 shows a variant analogous to FIG. 9, with the difference that the center recess 5 has a constant diameter over the entire length of the supply section 4.

Figure 1 1 shows an embodiment with four cooling channels 3. Figure 12 shows a variant analogous to Figure 1 1 with the difference that the center recess 5 has a constant diameter over the entire length of the supply section 4. Figure 13 shows a variant in which the joining zone 6 with respect to

Tool body 1 "far back" is located, that is, that the length c of the

Supply section 4 is about the same size as the length a of

Exit section 2. Figure 14 shows a variant analogous to Figure 13 with the difference that the center recess 5 has a constant diameter over the entire length of the supply section 4.

List of reference numbers used:

1 tool body

2 exit section

21 primary cutting section

22 secondary cutting section

3 cooling channel

4 supply section

5 center recess

6 joining zone

7 transfer area

8 transfer cavity

81 transfer channels

82 distribution chamber

9 spiral groove

10 spiral bridge

1 1 chip space

12 clamping section

13 working end face

D diameter

DIK partial circle

Diameter of the inner recess

longitudinal axis

radial direction

Claims

claims

1 . Tool body (1) for a rotating tool, in particular drill or end mill, comprising along its longitudinal axis (L):

- An outlet section (2), which, at least in sections, spirally extending internal cooling channels (3), and

- A supply section (4) with at least one substantially straight and parallel to the longitudinal axis (L) extending center recess (5),

- A joining zone (6), via which the outlet section (2) and the

Supply section (4) are interconnected,

wherein a transfer area (7) is formed, in which the

Mittenausnehmung (5) via at least one transfer cavity (8) communicating with the cooling channels (3) of the outlet portion (2) communicating,

characterized in that the outlet section (2) and the supply section (4) in the joining zone (6) are interconnected via a sintering joint, wherein the joining zone (6) extends along a cross section of the tool body (1) and transversely to the longitudinal axis (L). extends.

2. Tool body (1) according to claim 1, wherein the joining zone (6) is formed blunt and substantially perpendicular to the longitudinal axis (L).

3. Tool body (1) according to claim 1 or 2, wherein the

Transfer cavity (8) having transfer area (7)

- Completely in the outlet section (2) or

- completely in the service section (4) or

- overlapping in the outlet section (2) and in the

Supply section (4) is formed.

4. Tool body (1) according to one of the preceding claims, wherein the transfer cavity (8) in the form of obliquely to the longitudinal axis (L) 2 and substantially rectilinear transfer channels (81) is formed.

Tool body (1) according to one of claims 1 to 3, wherein the transfer cavity (8) in the form of a distribution chamber (82) is formed.

Tool body (1) according to one of the preceding claims, wherein at the outlet section (2) has a primary cutting portion (21) with at least two spirally extending flutes (9) and

Spiral webs (10) is formed, wherein the inner cooling channels (3) extend in the spiral webs (10).

Tool body (1) according to claim 6, wherein the flutes (9) of the primary cutting portion (21) have a first spiral angle (θι), with 15 ° <θι <30 °.

Tool body (1) according to one of the preceding claims, wherein at the supply portion (4) a secondary cutting portion (22) is formed, which has at least one along the longitudinal axis (L) extending chip space (1 1).

Tool body according to claim 8, wherein the secondary

Cutting section (22) over a length greater than 20% of

Supply section (4), preferably over a length greater than 40% of the supply section (4) extends.

10. Tool body according to claim 8 or 9, wherein the central recess (5) of the supply section (4) in that region of the

Supply portion (4) on which the secondary cutting portion (22) is formed, has a smaller diameter than in that region supply portion (4) on which no chip space (1 1) is formed. 3

1 1. Tool body according to one of claims 8 to 10, wherein the

at least one chip space (1 1) of the secondary cutting portion (22) one of the flutes (9) of the primary cutting portion (21) deviating depth and / or a different spiral angle (θ ₂ ).

12. Tool body according to one of claims 8 to 1 1, wherein the

at least one chip space (1 1) of the secondary cutting portion (22) has a spiral angle (θ ₂ ) between 0 ° and 30 °.

13. tool body (1) according to one of claims 8 to 12, wherein the at least one chip space (1 1) of the secondary cutting portion (22) over the length of the secondary cutting portion (22) variable spiral angle.

14. Tool body (1) according to one of the preceding claims, wherein the tool body (1) is formed of hard metal.

15. Tool body according to one of the preceding claims, wherein the outlet section (2) and the supply section (4) made of hard material of different hard material composition.

16. Tool body (1) according to claim 15, wherein the outlet section (2) consists of a hard material composition of higher hardness than that of the hard material composition of the supply section (4).

17. Tool body according to one of claims 15 to 16, wherein the

Hard material is designed as a hard metal and the hard metal composition of the supply section (4) recycled

Carbide contains.

18. Tool body (1) according to one of claims 15 to 17, wherein the hard material contains a binder and the hard material of

Supply section (4) one of the hard material of the outlet section (2) deviating binder composition and / or one of the hard material of the outlet section (2) deviating binder content. 4

19. Tool body (1) according to one of the preceding claims,

wherein the ratio of the length (c) of the supply section (4) to the length (a) of the exit section (2), c / a is greater than 1, 5, c / a is preferably greater than 3, c / a is more preferably greater than 5.

20. Tool body (1) according to one of the preceding claims,

wherein a pitch circle diameter (DIK) which circumscribes the internal cooling channels (3) of the outlet section (2) is greater than a diameter (DPK) of the central recess of the supply section

(4) in the transfer area (7).

21. Tool body (1) according to one of the preceding claims,

wherein the supply portion (4) has a clamping portion (12) on which no chip spaces (1 1) are formed.

22. A method for producing a tool body (1) for a rotating tool with the steps:

Providing a spirally extending internal cooling channels (3) having outlet portion (2),

Providing a supply section (4) with at least one substantially straight and parallel to a longitudinal axis (L) of the

Supply section (4) extending center recess (5),

- Forming at least one transfer cavity (8) at a front end of the outlet portion (2) and / or the supply portion

(4)

Sintering the exit section (2) with the supply section (4) to the tool body (1), so that the transfer cavity (8) the

internal cooling channels (3) of the outlet section (2) communicating with the central recess (5) of the supply section (4) connects.

23. A method for producing a tool body according to claim 22, wherein the transfer cavity (8) in the form of obliquely to the longitudinal axis (L) and substantially rectilinear transfer channels (81) 5 is formed in such a way that the transfer channels (81) - based on a cross-sectional area of the outlet section (2) and the supply section (4) - of a pitch diameter (DIK), which circumscribes the inner cooling channels (3) of the outlet section (2) , extend to the diameter (DPK) of the central recess (5) of the supply section (4).

24. A method for producing a tool body according to claim 22, wherein the transfer cavity (8) in the form of a distribution chamber (82) of cylindrical and / or frusto-conical shape is formed whose diameter (DVK) on the cooling channels (3) side facing at least the Partial diameter (DIK), which circumscribes the inner cooling channels (3) of the outlet section (2), corresponds.

25. A method for producing a tool body according to one of

Claims 22 to 24, wherein the supply portion (4) is formed of a different hard material composition than the outlet portion (2).

26. A method for producing a tool body according to one of

Claims 22 to 25, wherein the supply section (4) and the discharge section (2) are sintered prior to sintering joining.

27. A method for producing a tool body according to one of

Claims 22 to 26, wherein the supply section (4) and the outlet section (2) are produced by extrusion.

28. A method for producing a tool body according to one of

Claims 22 to 27, wherein the at least one transfer cavity (8) is introduced by a green processing.