Lathe tool, in particular boring tool.

(54) Title: ROTATING TOOL, IN PARTICULAR DRILLING TOOL.

(54) Title: LATHETOOL, IN PARTICULAR BORING TOOL.

(57) Summary

The rotary tool, in particular drilling tool (2) has a receiving part configured as a drill body (6) and a front part configured as a drill head (4), which extend along a central axis (8) and they can be detachably fixed to each other through a drag connection. The drive connection comprises at least two coupling pairs separated from each other and arranged eccentrically with respect to the central axis (8). Each coupling pair is made up of interlocking coupling elements, namely a receiving bag (20) and a drive pivot (18). The coupling elements are configured in such a way that after the union of the drill head (4) and the drill body (6), they are centered with each other and oriented aligned through the coupling elements. For this purpose, the coupling elements (18, 20) have an asymmetric cross-sectional area and they widen increasing the distance with respect to the central axis (8) for good torque transmission. By means of this configuration, a reliable transmission of high torques is also achieved compared to the solution known from the state of the art with lower stresses of the drill body (6) in the area of ​​the drive connection. At the same time, through the special configuration, an auto centering of the two parts of the tool is carried out with respect to each other.

(57) Abstract

The lathe tool, in particular the boring tool (2) has a receiving part implemented as a borer body (6) and a front part implemented as a borer head (4), which extend along a central axis (8) and can be removably fastened to one another via a driver connection. The driver connection comprises at least two coupling pairs which are separate from one another and are disposed eccentrically relative to the central axis (8). Each coupling pair is formed by interlocking coupling elements, namely a receiving pocket (20) and a driver pin (18). The coupling elements are implemented such that upon joining of the borer head (4) and the borer body (6), they are centered to one another and oriented aligned via the coupling elements. The coupling elements (18, 20) have an asymmetrical cross-sectional area for this purpose and widen with increasing distance to the central axis (8) for good torque transmission. Through said design, a reliable transmission of even high torques is achieved in comparison to the solution known from the prior art with lower strains of the borer body (6) in the area of ​​the driver connection. Simultaneously, an automatic centering of the two tool parts to one another is performed by the special design.

ROTATING TOOL, IN PARTICULAR TOOL

DRILL

Background of the Invention

The invention relates to a rotary chip removal machining tool, in particular a drilling tool, with a receiving part and a front part, which extend along a central axis and are detachably fixed to each other

<td>through</td><td>of a connection</td><td>drag.</td><td></td><td></td><td></td>

<td>A</td><td>tool of</td><td>mechanization</td><td>by</td><td>start</td><td>of</td>

<td>shavings</td><td>of this type</td><td>configured</td><td>how</td><td colspan="2">tool</td>

<td colspan="3">drill can be deduced from</td><td>of the</td><td>document</td><td>WO</td>

2007/107294 Al. This drilling tool is a modular tool for chip removal machining, featuring a replaceable tool head, which can be detachably connected to a shaved drill body via the drive connection . The drive connection here comprises a drive rib disposed on the underside of the drill head and extending transversely over

- 2 a longitudinal median axis. This drive rib is inserted into a drill body receiving bag, corresponding to the shape of the drive rib. The receiving bag in this case surrounds the drive rib on the entire periphery.

The drive connection is generally used to transmit the torque between the two parts of the tool. In such drive connections there is often a conflict between a drive rib as stable as possible for torque transmission and as little weakening of the drill body as possible.

Scope of the invention

The invention has the task of indicating a tool of the type mentioned at the beginning with an improved drag connection, which is designed for the transmission of high torques and at the same time causes a reduced weakening of the receiving part, to guarantee a return stable of the tool.

Solution of the mission

The task is solved according to the invention by means of a tool with the characteristics of claim 1. The tool is, in general, a rotation tool for chip removal machining of a workpiece. The tool is made up of several parts, in particular two parts, and comprises a receiving part and a front part. In the case of a drilling tool, the receiving part is the drill body and the front part is the drill head. In the case of a milling tool, the receiving part would be a brake shank and the front part would be a milling head. These two parts, which extend along a median axis (axial direction), are detachably attached to each other by means of a drag connection. It has two coupling pairs separated from each other and arranged eccentrically with respect to the middle axis. Each of the coupling pairs is in this case formed by two interlocking coupling elements, namely, on the one hand, a drive pivot and, on the other hand, a totally surrounding receiving bag. The coupling elements serve, on the one hand, for the transmission of torque forces between the two parts. On the other hand, the two coupling components also serve for the alignment at the level of the two parts with each other, that is to say, that through the coupling elements the two parts are central to each other and in relation to the central axis. With respect to this dual function, the coupling elements are asymmetrically configured and widen - seen in the plane perpendicular to the median axis - increasing the distance from the central axis. Ά Through the asymmetric configuration, automatic centering of the two parts is achieved, especially after the joint of the two parts. At the same time, with the widening increasing the radial distance with respect to the central axis, the drag connection is especially strong in the radially outer zones, so that high torsional wall forces can be transmitted.

By asymmetrical configuration of the coupling elements, it is understood in this case that they have a cross-sectional area oriented perpendicular to the central axis, that they do not have symmetry with respect to the axis of rotation or with respect to a plane.

A special advantage of this configuration can be seen in that the two coupling pairs are separated from each other and are respectively arranged eccentrically with respect to the central axis. Therefore, in the area of ​​the central axis itself, no modification is provided through the drive connection in the receiving part or in the front part. Preferably, the two parts are present in the area of ​​the central axis flat on each other, without interlocking in this area. Therefore, the individual coupling pairs are displaced to a radially outer zone. In this way, the core of the tool remains unaffected by the drag connection.

Investigations have shown that this configuration with the two eccentric coupling pairs and separated from each other, compared to the configuration as described in WO 2007/107294 Al, leads to a reduction of the stresses in the drill body, that is, in the reception part. Loading of receiving part

- with the same or improved torque transmission it is reduced by approximately 20%. Furthermore, through the separate arrangement, the central area is free so that coolant holes, tensioning bolts, etc. can now be easily inserted. In addition, the increased free space in the area around the central axis enables greater configuration freedom with respect to the configuration especially of the chip removal grooves. These can now be clearly approximated closer to the central axis.

In accordance with a convenient configuration, the drive pin is here configured as a prism. In the same way, the receiving bag is also configured, adapted to the drag pivot, as a prismatic housing.

By configured as a prism, it is meant that the two coupling elements respectively have an approximately polygonal base surface with side walls preferably extending parallel to the central axis. In particular, a base surface with 4 angular zones is provided.

The corner areas are in this case configured conveniently rounded. Nor should the connection between the individual corner zones necessarily be linear.

The special advantage of this prismatic configuration can be seen in that adjacent side walls serve for automatic fixing or centering of the two parts. In the sense of as stable a configuration as possible, it is preferably provided in this case that the expansion of the respective drive pivot in the radial direction is preferably greater than 50% of the tool radius. The two coupling elements are preferably configured to be rotationally symmetrical with respect to one rotation about the central axis.

In the preferred configuration with two coupling pairs, the coupling elements are therefore symmetrical with each other with respect to a rotation about the central axis around 180 °. As an alternative to this, in principle, there is also the possibility of configuring the coupling elements asymmetric with each other.

In accordance with a suitable development, it is provided that the coupling elements comprise, respectively, radially outwardly arranged, especially curved outer bearing surfaces, as well as other drive surfaces. In the case of loading, that is, during a transmission of the torque, both the outer bearing surfaces and the driving surfaces of the two coupling elements connected to each other are mutually pressed. The outer bearing surfaces and the driving surfaces are separated in this case from each other. More conveniently, they form adjacent lateral surfaces of the prism, through which the automatic central is made.

Preferably, in this case, the drive surfaces are oriented essentially in the radial direction, to enable the most optimal transmission of force for driving the torque.

In this case, essentially oriented in the radial direction is meant in particular that the drive surfaces are oriented with respect to the radii at most up to an angle of ± 20 °, preferably ±

10°.

More conveniently, the receiving bag has an outer rib comprising the outer bearing surface, which widens towards the loaded area in case of loading of the outer bearing surface. The outer rib in this case also forms the outer side of the tool with its outer side. The outer bearing surface, which extends essentially concentric to the outer wrapping surface of the tool, therefore deviates, in accordance with the preferred configuration of the concentric arrangement, in the sense that the width of the area of ​​the wall increases towards the loading areas.

Preferably, the receiving bag comprises at least one rib-like and elastic wall area.

This area of ​​the wall is thin enough and therefore elastic so that in the case of load, when the forces of the torque appear, an elastic deformation of the area of ​​the wall can be carried out, so that it is configured a surface contact between the elastic wall area and an associated surface section of the drive pivot. Therefore, by virtue of this configuration, automatic tolerance compensation is carried out between the two contact surfaces between the drive pivot and the receiving bag, to achieve a desired flat support surface for torque transmission. torsion. Such inaccuracies of tolerance are conditioned, for example, by measurement inaccuracies during the manufacture of the receiving bag and / or the drive pin. In this case, it should be noted that the receiving part (drill body) is designed for many front parts (drill head), which represent wear parts.

In general, the areas of the wall of the receiving bag, which surround the drag pivot, are configured of the rib type with a reduced width compared to the drag pivot.

With respect to the intended self-centering of the two parts of the tool with respect to each other, the two coupling elements present for play a play with each other and, in addition, different geometries of the cross section, in such a way that insignificant relative movement is possible between the two coupling elements connected to each other. During such relative movement, the coupling elements are mutually tensioned. Preferably in this case the curved outer bearing surfaces rest against each other. Since the two coupling elements are supported on the outer bearing surfaces in a radial direction with respect to each other, a force component directed radially inwards is exerted on the respective drive pin. Since this is done on each coupling pair, this leads to the desired automatic centering of the two parts of the tool. Preferably, the outer bearing surfaces of the two coupling elements of a coupling pair are eccentric with each other. By this it is understood that the outer bearing surfaces extend along a circular path with a defined radius of curvature, so that the midpoints of the circles are arranged offset from each other. In addition, different radii of curvature can also be provided for the outer bearing surfaces.

Preferably, the clearance is selected in this case in such a way that the two coupling elements have a free turning angle in the range of 1 to

5 °, that is, they can be rotated with each other in a limited angular zone of maximum 1 ° to 5 °.

At least one bore extending essentially in the axial direction extends through the drive pivot, which is aligned with a corresponding bore in the receiving bag. This hole is preferably a coolant hole or also a hole for receiving a fixing means, such as a screw. More conveniently, two holes are provided in the drive pivot, namely a hole for a coolant and a hole for a fixing means, especially a tensioning screw. Both are aligned with corresponding holes in the receiving bag.

<td colspan="4">15 The drill intended for receiving</td><td rowspan="2">of of</td><td rowspan="2">a screw way more</td>

<td>tensioner is</td><td>oriented</td><td>in</td><td>this case</td>

<td>convenient</td><td>inclined</td><td>with</td><td>about</td><td>the</td><td>direction</td>

<td>longitudinal</td><td colspan="2">and in particular,</td><td>in such a way</td><td>than</td><td>during the</td>

tightening the tensioning screw, the two coupling elements are tensioned against each other. The inclined position is selected in this case in such a way that a clamping is preferably carried out in both the circumferential and axial directions. The longitudinal axis of the bore is in this case inclined a little in the circumferential direction, more precisely in the tension direction, in which the drive pivot is tensioned against the receiving bag. The longitudinal axis of the drill therefore extends approximately within a tangential plane, more precisely within the plane that is covered by the axial direction and the clamping direction. The longitudinal axis of the hole, which is in this plane, presents an angle of inclination with respect to the axial direction greater than 1 ° in the interval between 3 ° and 20 ° and preferably in the interval of approximately 10 °.

According to a convenient configuration, a compensating element is arranged between the receiving bag and the drag pivot, preferably extending in an axial direction parallel to the central axis, such that, in the case of load, it is superficially supported both in the trailing pivot and in the receiving bag. Therefore, in the case of loading, a force, exerted by the drag kingpin, is transmitted on the receiving bag. The compensating element is in this case particularly free to rotate about its longitudinal axis. This compensation element serves for tolerance compensation to enable a desired surface support of the surfaces involved in the transmission of force. The compensation element is compensated for measurement inaccuracies conditioned by the manufacturing or possibly also conditioned by the operation.

To this end, the compensation element preferably has a cross-sectional area of ​​the circular segment type. The compensating segment is therefore approximately semi-cylindrical in shape and has a partially cylindrical bearing surface as well as a flat bearing surface. Furthermore, provision is made for the compensating element to have a cylindrical clamping shank, with which it is inserted into a shank housing, configured as a bore, in the receiving bag, so as to enable a rotational capacity of the compensating element. inside the reed housing. In this case, the compensating element is preferably arranged in an angular area of ​​the prismatic coupling elements and, in particular, in particular in the angular area, which connects the outer bearing surfaces with the drive surfaces. For the possibility of free turning capacity, it is further provided in a convenient configuration that the receiving bag has an angular hole and that the drive pivot is flattened in the corresponding angular area. Due to the angle drill, sufficient rotary movement of the compensation element is possible.

The compensating element and at least one of the coupling elements are in this case preferably made of a material of different hardness. The compensating element can be softer or also harder than the at least one coupling element. Due to the different hardness of the material, additional adaptation and additional tolerance compensation are possible through plastic deformation.

In order to ensure a secure fixing of the two parts to each other in the desired position, a tensioning installation is provided, according to a suitable development, which can be activated from the side and through which the drive pivot can be tensioned with the reception bag. In this case, tensioning is understood in particular to mean tension in both the circumferential and axial directions, so that the two coupling elements are brought to their theoretical position relative to one another. This tensioning installation is preferably used as an alternative to the tensioning screw already described, which is oriented essentially in the axial direction and is activated from the front side. The lateral tensioning installation, which can therefore be activated from the wrapping surface of the rotary tool and which is also oriented approximately tangentially on the rotary tool, has the advantage that no modifications should be made to the front.

More conveniently for the configuration of the tensioning installation, a tensioning pivot extending in the longitudinal direction is arranged in the drag pivot, which penetrates into a pivot housing of the receiving bag. Additionally, a tensioning element is provided, which acts laterally on the tensioning pivot, to tension the drag pivot with the receiving bag. Through the additional arrangement of the tensioning pivot, a decoupling of the tensioning installation from the dragging pivot is achieved. Therefore, the trailing pivot is not weakened. Preferably, the drive pivot penetrates tension-free into the pivot housing, even in the tensioned state between the receiving bag and the drive pivot. Therefore, also in the tensioned state, the tensioning pivot presents a play with respect to the pivot housing. More conveniently, the tensioner powder is in this case arranged asymmetrically and off-center on the underside of the drive pivot.

Preferably, alternatively to the configuration with the tensioning pivot, the tensioning installation has an element that is movably received in one of the coupling elements, for example a threaded element, such as a threaded pin or a bolt, so that the element supports with one of its front sides for tensioning on the other coupling element. Therefore, in the configuration as a threaded pin, it is rotated inwards or outwards in the respective coupling element, until the threaded pin rests on the other coupling element and thus tightens the two coupling elements. one against the other.

This tensioning installation is also configured in such a way that tensioning is carried out both in the circumferential and in the axial direction.

More conveniently, the element is movably accommodated in a through hole of one of the coupling elements, so that the element can also be supported with its second front side on the other coupling element. This serves to loosen the drag connection when several coupling elements are tensioned together.

An inventive development of the invention by itself consists of inserting a supporting element in the coupling area, that is, in the area of ​​the separation joint between the drill body and the drill head.

The support element can be made of a specially adapted material and serves for the selective stabilization of the tool in the coupling area. The support element serves to damp any possible movements or oscillations of the drill bit body and of the drill head relative to each other. In particular, opposing vibrations of the bit head and bit body should be reduced or neutralized to reduce wear from tool vibrations. In addition, the transmission of body sound in the area of ​​the gap between the drill body and the drill head must be reduced or eliminated. Also this reduction in the transmission of body sound leads to an improvement in the properties of the tool.

In particular, such tools are suitable for cross drilling in workpieces with large drilling depth. Furthermore, the tools are also suitable for drills with inclined drill outlets.

In a first configuration, the support element is configured as a disk parallel to the plane of the frontal surfaces, adjacent to each other, of the drill body and the drill head. Preferably, this disc-shaped support element is in the form of a circular ring segment beyond the enveloping surfaces of the drill body and drill head and thus supports the drilling tool against the wall of the drill. In this way, the operation of the drilling tool in the drill is stabilized, while the cuts in the drill head can mechanize by chip removal the wall of the drill.

Another preferred embodiment of the

<td>support for</td><td>has a conformation</td><td>of the</td><td>type</td><td>ring</td><td>than</td>

<td>5 flap</td><td colspan="2">wrapping surfaces or</td><td>all right</td><td>of the body</td><td>of</td>

<td>drill</td><td>or the drill head or</td><td>of the</td><td>Body</td><td>drill bit and</td><td>the</td>

<td>head</td><td>bit at the same time.</td><td>This</td><td colspan="2">realization has</td><td>the</td>

Advantage that the support element is supported, by way of a sliding ring, on a large surface on the wall of the hole. Furthermore, in a cup-type configuration of the support element with a base body configured as a disk parallel to the plane and with a ring-shaped conformation, a particularly good accommodation of the drill body and the drill head is guaranteed in the docking area. In another configuration, recesses corresponding to the chip removal grooves formed in the drill body and in the drill head may be provided in the support element to optimize the transport of the chips. The comparatively large outer peripheral surface of the ring-type shaping on the bearing element enables the application of special guide elements for guiding the drill tool on the wall of the drill. These guide elements can be configured in the form of a slat, in the form of a projection and in other geometries to improve the concentric running of the tool in the drill. These guide elements can be inserted by joining the material on the outer surface of the ring element. But it is also possible to fix them by clamping on the ring element.

In another configuration, the support element may have a coating, especially in the area of ​​the ring type conformation. The coating can serve to prevent wear on the outer surface of the ring facing the wall of the drill. The coating can also influence the remaining vibration and transmission properties of the tool.

In another embodiment of the invention, the ring-type shaping, especially in the configuration as a receiving cup, can be configured at the same time as a flex spring. In this configuration, the ring element drives the wall of the hole with its spring force and thus counteracts a movement of the tool out of its centered position with the spring force in action.

Therefore, the tool is elastically guided on the wall of the drill. In this way, the support element forms a damping member for the tool in front of the workpiece to be machined.

Description of the figures

Exemplary embodiments of the invention are explained in detail below with the aid of the figures. These show in partially schematic representation:

Figure 1 shows a fragmentary perspective representation of a modular drilling tool.

Figure 2 shows a perspective view of the rear side of a drill head of the drilling tool according to Figure 1 with drag pins of a first embodiment variant.

Figure 3 shows a top perspective view on the front front side of a drill bit body of the drilling tool according to figure 1 with receiving bags of the first embodiment variant.

Figures 4a-c show a schematic top view on the drag connection between the bit body and the bit head (Figure 4a) of a second variant of embodiment as well as fragmentary sectional views with respect to the intersection lines 4b5 4b and 4c-4c, respectively, represented in Figure 4a.

<td>Fig. 5</td><td>shows a</td><td>view</td><td>higher</td><td>schematic</td>

<td>about connection</td><td>drag</td><td>of the</td><td>first</td><td>variant of</td>

<td>realization.</td><td></td><td></td><td></td><td></td>

<td>Fig. 6</td><td>shows a</td><td>view</td><td>higher</td><td>schematic</td>

<td>about connection</td><td>drag</td><td>Similary</td><td colspan="2">to figures 4a and 5</td>

of a third variant of embodiment.

FIG. 7 shows a perspective view of the drill head on the drive area according to the third embodiment variant.

FIG. 8 shows a top perspective view of the bit body drag zone according to the third embodiment variant.

Figures 9a, b show a top view (9a) on the front side of the drill body as well as a sectional view through the drill head (figure

9b), in which the intersection plane is determined by the intersection line 9b-9b in Figure 9a.

FIG. 10 shows a perspective view of the drag connection of the drill head according to a fourth embodiment variant.

FIG. 11 shows a schematic view of the drive connection according to a fifth embodiment variant, which forms a combination of the third and fourth embodiment variants.

FIG. 12 shows a perspective view of the driving area of ​​the drill head according to a sixth embodiment variant.

Figure 13 shows a schematic top view on the drag connection according to the sixth embodiment variant.

Figure 14 shows a partially sectional view in the area of ​​a tensioning pivot according to the sixth embodiment variant along the line of intersection 14-14 in Figure 13.

Figure 15 shows a general drawing of a partial area of ​​a first embodiment of the drilling tool with support element.

FIG. 16 shows the drilling tool shown in FIG. 15 in an ordered exploded view.

Figure 17 shows a view on the coupling surface of the drilling head according to figure 15.

Figure 18 shows a view of a support element, configured as a disk parallel to the plane, according to Figure 15.

Figure 19 shows a top plan view on the coupling surface of the drill body of figure 15.

Figure 20 shows an ordered exploded representation of a drill body and a support element with a bilateral receiving cup.

Figure 21 shows the exploded representation of Figure 20 with a support element with an active receiving cup in the direction of the drill body.

FIG. 22 shows an embodiment example, modified with respect to the embodiment example shown in FIG. 21, of a support element with an enlarged receiving cup.

Figure 23 shows an embodiment of the support element with guide elements on the outer peripheral surface of the ring-shaped conformation.

Figure 24 shows an embodiment of a ring-shaped conformation configured as a flex ring, configured as a receiving cup, and

Figure 25 shows a section through the ring type conformation, configured as a flex spring, shown in Figure 24.

Equivalent parts are provided in the figures with the same reference signs. The drive connection is described below with the aid of a drilling tool in different embodiment variants. The drive connection can in general also be transmitted over other chip removal machining tools for coupling two parts of a tool. The individual characteristics described below on the different variants and the constructive configurations can also be combined with each other, as long as they are not excluded.

Description of the embodiment examples

The drilling tool 2 represented in the figure is modular and comprises a drill head that forms the front part, which is replaceably fixed in a drill body 6 that forms the receiving part. The drilling tool 2 extends axially or longitudinally along a median axis 8. In the exemplary embodiment, the drill head 4 has a central drill tip 10 configured as a cutting insert as well as two cutting plates 12 arranged radially on the outer side. A total of four coolant outlet holes 14 can be recognized on the front front side of the drill head 4. The cutting plates 12 are oriented with their flat free side towards a chip removal groove

15, which starts at the drill head 4 and continues in the drill body 6 as a helical chip starter groove 15. The drill head 4 can be threaded with the drill body 6 with the help of tensioning screws 16, which are guided from the front side by means of the drill head 4 through it.

The bit head 4 and the bit body 6 are detachably fixed to each other by means of a drag connection.

As can be deduced from Figures 2 and 3, the drive connection comprises two drive pins 18, which are arranged on the underside of the drill head 4 spaced from each other and off-center with respect to the central axis 8. In the assembled state, the drive pins fit into a respective corresponding receiving bag 20 of the bit body 6. Drive pins 18 are configured as prism type elevations starting from the flat bottom side of the drill head 4. In the same way, receiving bags 20 are configured as prism type cavities starting from a surface. smooth face of drill bit body 6. The drive pins 18 are each crossed by a coolant hole 22 as well as a fixing hole 24, which are respectively aligned with associated holes 22 ', 24' on the flat surface of the bottom of the receiving bag

twenty. The coolant bores 22, 22 'are fed by a second coolant channel 26 in a manner not shown in detail.

The drive pivots 18 are delimited, respectively, by a front surface, · which is in a plane perpendicular to the central axis 8 as well as by a peripheral or enveloping surface, which is oriented parallel to the central axis. In addition to this, the respective receiving bags 20 are also configured.

Of particular importance is the separate configuration of the two drag pins 18 and their complete accommodation, surrounding on all sides, in the receiving bags 20. The drag pins 18 as well as the receiving bags 20 have a special geometry, which is he explains still further. The cross-sectional area -perpendicularly to the central axis- of each coupling element 18, 20 is marked by an asymmetry. This ensures that a very good torque transmission is carried out through the drive connection with the lowest possible tension load of the drill body 6 in the area of ​​the receiving bags.

twenty. At the same time, the drive pins 18 in connection with the receiving bags 20 are formed and arranged in such a way that automatic centering of the two parts 4, 6 relative to each other is performed. Each of the pull pins 18 forms with the receiving bag. twenty Corresponding thereto a coupling couple, the drive pins 18 and the receiving bags 20 generally form complementary coupling elements with each other which - except for the insignificant differences still described below - have identical cross-sectional geometries.

As can be deduced from figure 4a, the coupling elements have, respectively, a roughly polygonal cross-section contour (considered in a plane perpendicular to the central axis

8). In the exemplary embodiments, the coupling elements 18, 20 respectively have four angular zones, which are respectively rounded. The coupling elements generally have a trapezoidal cross-sectional area in the embodiment examples. Between the individual corner areas, respectively, wall sections are configured. Figure 4a shows the drive connection in the loaded state, that is, when the individual coupling elements 18, 20 support each other for the transmission of torque. As it can be deduced from figure 4a, in this case two areas of the wall support each other respectively. One of the wall areas is the area of ​​the wall that is radially outside, in which the coupling elements

18, 20 abut each other through outer bearing surfaces 28. These surfaces are curved and extend concentrically to the outer peripheral side of the drilling tool 2 in the embodiment of FIG. 4a. The two coupling elements 18 , 20 are further supported by each other with drive surfaces 30 adjacent to support surfaces 28. These surfaces are oriented, in the embodiment of FIG. '4a, essentially radial to the central axis 8. The other two areas of the wall of the coupling elements present, respectively, a play with each other, so that, in general the drive pins 18 play into the respective receiving bag 20. These other areas of the wall therefore have no function with respect to the transmission of the torque and do not serve to center the two parts 4, 6 with respect to each other. In the exemplary embodiment, these areas of the wall are oriented approximately perpendicular to each other and extend, respectively, parallel and spaced from the two planes, which are also arranged at a right angle to each other and respectively receive the central axis 8 per se.

As can be deduced from the sectional representations of figure 4b, the two coupling elements 18, 20 bear directly on each other in the area of ​​their drive surfaces 30. At the same time, it can be recognized that the head of Drill bit 4 rests, with its flat underside, flat on the smooth front surface of drill bit body 6. The underside of drive pin 18 is instead spaced from the bottom surface of receiving bag 20. Finally, from figure 4c it can still be recognized that the rear wall areas, not involved in the transmission of torque, of the two coupling elements 18, 20 are spaced from each other.

During mounting of the drill head 4 in the drill body 6, the drive pins 18 are first inserted into the receiving bags 20. The drill head 4 is then rotated to a negligible extent relative to the drill bit 6, so that by virtue of this relative rotation, the drill head and drill body 6 are tensioned to each other through the coupling elements 18, 20. For the explanation of this process, in figure 5, in the left half of the figure, the coupling pair is shown in the non-tensioned state and in the right half of the figure in the tensioned state. Figure 5 shows the variant embodiment, as can also be deduced from Figures 2 and 3.

Figure 5 shows the radii of curvature r_x, r₂ of the outer bearing surfaces 8 of the drive pivot 18 (r_x) and the receiving bag 20 (r₂), respectively. As can be recognized, the center points of the radii of curvature are arranged offset from each other, so that, in general, the drive pins 18 are arranged eccentrically with respect to the receiving bags 20. Through this measurement, during in rotary motion, the corresponding outer bearing surfaces 28 are tensioned against each other. Due to the 180 ° symmetry in the example of embodiment of the two coupling pairs, during this rotary movement, the automatic centering of the drill head 4 is carried out in relation to the drill body 6. The coupling elements 18, 20 are rotatable with each other in this case around an angle of free rotation a that is in the range of a few degrees, in the exemplary embodiment in the range of 2 °.

Except for this eccentric configuration, the two coupling elements 18, 20 are of the same type, that is, they are configured with the same geometry of the cross section. For the game setup, which can be recognized well from the left half of the figure

5, only the drag pins are configured a little smaller than the receiving bags.

While in the example of embodiment of the figure

4a, the drive surfaces 30 extend concavely inwards with respect to the angular zone radially inside, the drive surfaces 30 according to the embodiment according to FIG. 5 extend essentially linear, deviating under an angle of a few degrees from the radial, which extends through the central axis

8.

The third variant embodiment shown in FIG. 6 is based on the variant embodiment according to FIG. 5. Here too, the left half of the figure shows the untightened state and the right half of the figure shows the tensioned state. Unlike the exemplary embodiment of FIG. 5, a compensating element 32 is arranged in the angular area, which connects the drive surfaces 30 with the outer bearing surfaces 28. The compensating element 32 is configured as an adjusting pin, extends parallel to the central axis 8 and has, seen in cross section, a surface of the circular segment type. By virtue of the compensation element 32, the respective angular area of ​​the drive pivot 18 is flattened, as can best be seen from FIG. 7. The compensation element 32 has at its rear end a cylindrical fixing rod 34, with which it is inserted in a cylindrical rod housing 36 (figure 8) in the bottom of the receiving bag 20. The compensation element 32 is rotatable about its longitudinal axis in the reed housing 36.

The compensation element 32 is arranged in the loaded area of ​​the coupling elements 18, 20, namely, between the drive surfaces 30 and the outer bearing surfaces 28. The drive pivot rests with its flattened angular area on the the flat side of the compensation element 32 and it again rests with its rounded, semi-cylindrical side, in the angular area of ​​the reception bag. In this case, the angular area has the same radius as the compensation element 32. Due to the rotating capacity of the compensation element 32 and the flattened configuration on one side and rounded on the other side, the compensation element adapts automatically to the flat side of the drive pivot 18 so that a surface contact is formed between the drive pivot 18 and the compensation element 32. By virtue of the rounded configuration, with which the compensation element 32 rests on the wall of the receiving bag 20, here too a largely superficial contact is formed. In general, therefore, the compensation element 32 serves for compensation of tolerances, which are conditioned, for example, by manufacture or which are also configured in the course of operation.

In order to secure the compensation element 32 against a fall, it can be fixed, for example, with the help of a fixing lacquer on the shank housing 36. The fixing force is dimensioned in such a way that, in the case of load and in the case of a rotation necessary for tolerance compensation, the compensation element 32 is automatically rotated to the optimal position.

The drill head 4 is fixed to the drill body 6 through an additional tensioning mechanism, so that the drill head is tensioned in a defined axial position as well as in a defined rotational position in the clamping direction or peripheral direction against drill head 6.

According to a first variant embodiment, which is explained with the help of Figures 9a, 9b, a tensioning screw 16 is inserted from the front front side of the drill head 4 through the drill head 4, which is it extends through the fixing hole 24 of the drive pin 18 and can be screwed into an associated fixing hole 24 ', made as a threaded hole, in the receiving bag 20. The fixing holes 24, 24 'are not arranged parallel to the central axis 8, but inclined. The central axis of the fixing hole 24 extends in this case within a plane. This plane is covered by the axial direction and a clamping direction, which is indicated in Figure 9a by arrow 37. The clamping direction 37 is defined in this case by the direction, in which the drive pin it is tensioned against the receiving bag 20. In this case, the clamping direction is preferably oriented perpendicular to the trailing surface

30. The central axis of the fixing hole is inclined with respect to a parallel, which in this case extends to the central axis 8 (and therefore with respect to the drive surfaces 30) at an angle of inclination β of&gt; 1st in the range of 3 - 20 ° and preferably in the range of about 10 °. By virtue of this inclined orientation, the drill head 4 is tensioned in both the axial and clamping directions 37 against the drill body 6.

As an alternative to this tension clamp, which extends essentially in the longitudinal direction, with the aid of the tensioning screw 16, through the 'tool head 4, according to a preferred alternative, a lateral tensioning installation is provided. This can be activated from the peripheral side of the drill body

6. The special advantage can be seen in that no holes, which weaken the drill head 4, should be provided for the tensioning screw 16. This lateral tensioning installation is explained in detail below in two different embodiment variants in relation to FIGS. 10 to 14.

In the first variant embodiment, which is explained with the help of Figures 10 and 11, the tensioning installation comprises a threaded pin 38, which can be adjusted with the help of a tool 40 in a threaded hole

<td>corresponding in</td><td></td><td>the</td><td colspan="2">pivot of</td><td>drag</td><td> 18</td>

<td>correspondent. TO</td><td>such</td><td>end,</td><td>the</td><td>pivot</td><td colspan="2">trailed 18</td>

<td>Respective 15 presents</td><td>a</td><td colspan="2">drill</td><td>on the way</td><td>42 which</td><td>this</td>

<td>provided at least</td><td>in</td><td>a</td><td>zone</td><td>partial</td><td>with a</td><td>thread</td>

interior not shown here in detail. The threaded pin 38 has on its rear front side, accessible from the outside, a housing 44 for the tool

40, which is made in the embodiment as an internal hexagon (FIG. 10). A pivot 46 is integrally formed on its opposite front side. To hold the two coupling elements, the threaded pin 38 is unscrewed a little outside the through hole 40, so that the threaded pin 38 rests with a partial area of ​​its rear front surface in the area of ​​the wall of the receiving bag 20 and thus tightens the pull pin 18 in the desired direction. The threaded pin 38 is configured on its rear face surface to be approximately cup-shaped. In addition, the wall area of ​​the receiving bag 20 is also cup-shaped, so that in addition to tension clamping in approximately the peripheral direction, tension clamping in the axial direction is also performed.

For a change of the drill head 4, the threaded pin 38 is screwed in until the pivot 46 rests in the area of ​​the opposite wall of the reception bag 20 and in this way the tension clamp between the elements is released again. coupling, so that the drill head can be removed 4.

From figure 11 it is possible to deduce, in a still complementary way, another characteristic that refers to the compensation element 32. And, in particular - as it can be recognized from the left half of the figure - the angular area, in which the compensation element 32 is arranged, is formed by an angular hole in the reception bag 20, in such a way that there is a possibility of turning the compensation element 32 as freely as possible, to achieve the most superficial support possible between the flat sides of the drive pivot 18 and the compensation element 32.

The second variant embodiment of the tensioning device is explained in detail below with the aid of Figures 12 to 14. In Figure 13, the unstressed state is indicated again in the left half of the figure and in the right half of The figure indicates the tensioned state between the two coupling elements. In this variant embodiment, the drive pin 18 additionally comprises in each case a tensioning pin 48, which extends in an axial direction starting from the bottom side.

In the exemplary embodiment, the tensioning pin 48 has a roughly rectangular to elliptical cross-sectional contour and is arranged off-center on a marginal side. ,

The tensioning pivot 48 has a receiving hole 50 in the shape of a cone trunk, in which a tensioning element 52 configured as a screw fits with a point also in the form of a cone trunk (Figures 13 and

14). Through the cone-shaped, that is to say the conical termination, configuration of the receiving hole 50 and of the tensioning element 52, in addition to the tension clamping in the circumferential direction, a force component is also generated at the same time axial, to tension the drill head 4 in an axial direction against the drill body 6.

From FIG. 14 the generation of force in the axial direction can again be well recognized by virtue of the cone-shaped configurations. From this figure, it is also possible to recognize a notch-shaped cavity 54 on the upper front side of the fixing rod 34 of the compensation element 32.

This notch-shaped cavity 54 allows, for example, a screwdriver to be engaged in order to be able to rotate, during the first assembly, the compensation element 32 to a desired theoretical position.

The drill head 4 in FIG. 15 has on its cutting side 62 the drill tip 10 and at the periphery two cutting plates 12 opposite each other. Furthermore, in the area of ​​the drill head 4, coolant channels 65 and fixing means 66 are provided. The fixing means 66 serve, for example, for fixing the cutting plates 12 or for fixing the supports. cutting plates or the like.

The coupling side of the head 67 is remote from the cutting side 62 of the drill head 4. The coupling side of the head 67 carries the front surface of the drill head 4 which is directed towards the drill body 6. Starting from this front surface on the coupling side of the head 67, in the exemplary embodiment, two drive pins 18 protrude beyond the coupling side of the head 67 towards the drill body 6. Also the drive pins 18 again have the rear holes of the coolant channels 65.

The side of the drill body 6, which is facing the drill head 4, is the coupling side of the shank

70. The coupling side of shank 70 and the coupling side of head 67 form the coupling zone between drill body 6 and drill head 4. Two pockets are formed on the surface of the coupling side of shank 70 20, configured in a complementary way to the drag pivots 18. In the receiving bags 20, the refrigerant channels 65 can again be recognized, which are aligned in the final state of assembly with the refrigerant channels 65 in the drill head 4. The refrigerant channels 65 therefore pass to through the entire drill tool. Finally, both the drill head 4 and the drill body 6 respectively have a centering hole 72. Otherwise, free surfaces 73 can be recognized in the drill head 4 and in the drill body as well as helical chip removal grooves 15 made between the free surfaces 73.

The end of the drill housing body 6 of the tool, not shown in the figures, is remote from the coupling side of the shank 70 in the drill body 6. The drill body 6 is embedded with the housing end of the tool in the drill tool.

In the exemplary embodiment according to Figures and 16, the support element 7 5 is arranged between the drill head 4 and the drill body 6, configured as a plate parallel to the plane. The support element 75 has through holes 76 that correspond to the outer contour of the drive pins 18. With the help of the through holes 76, the support element 75 is easily attached to the drill head 4, so that the drive pins 18 pass through the support element 75 into the through holes 76. The drive pins 18 form this way a positive connection with the support element 75. For the final assembly of the tool, shown in Figure 15, the drive pins 18 first pass through the through holes 76, to then fit positively into the receiving bags 20 in the drill body 6. Also the support element 75 has a centering hole 72. Otherwise, the support element 75 has recesses 77 that correspond to the chip removal grooves 15.

From the representation of figure 15 it can be recognized that the support element 75 protrudes beyond the surface, surrounding the drill head 4 and the drill body 6, which is formed by the free surfaces 73. When the drilling tool is finally assembled, the support element 75 thus forms an annular zone 78, which protrudes beyond the envelope surface of the drilling tool, namely the drill head 4 and the drill body 6 During the drilling process, the support element 75 rests with this annular zone 78 on the wall of the drill and thus guides the tool against the wall of the drill.

The ordered exploded representation of FIG. 20 shows a drill body 6 identical to that of FIGS. 15 to 19. The support element 75 has, in the exemplary embodiment according to FIG. 20, a ring-type conformation 79. The shape 7 9 overlaps in the direction of the central axis 8 of the drilling tool both the coupling side 67 of the drill head 4 as well as the coupling side of the shank 70 of the drill body 6. The support element 75 represented in the figure thus forms a bilateral receiving cup for receiving both the coupling side 67 of the drill head 4 and also the coupling side of the shank 70 of the drill body 6.

In contrast to this, the exemplary embodiment of the support element 75 shown in FIG. 21 presents

- 47 exclusively a ring-type conformation 79, extending in the direction of the central axis 8 of the drilling tool towards the coupling side of the shank 70 of the drill body 6. In other words, the conformation 79 in the form The ring gear only overlaps the coupling side of shank 70 of drill bit 6 and at the same time rests as a plate parallel to the plane on coupling side 67 of drill bit.

4.

In contrast to this, the ring-shaped conformation 79 in the embodiment shown in FIG. 20 overlaps both the coupling side of the shank of the drill body 6 and also the coupling side 67 of the drill head 4 and in this way it forms a bilateral receiving cup both for the coupling side of the shank 7 0 of the drill body 6 and also for the coupling side 67 of the drill head 4. Instead, the exemplary embodiment according to FIG. 21 exclusively forms a receiving cup for the drill body 6, namely the coupling side of the shank 70 of the drill body 6.

The exemplary embodiment shown in FIG. 22 again shows a support element 75 with a receiving cup, active exclusively in the direction of the drill body 6, and with a plate parallel to the plane that rests on the drill head 4. In contrast to the exemplary embodiment shown in FIG. 21, the ring-shaped conformation 79 overlaps the coupling side of the shank 70 of the drill body 6 in this exemplary embodiment by a significantly larger amount. The extension of the shaping 79 in the direction of the central axis 8 with the mounted tool is clearly greater than in the embodiment shown in FIG. 21. In this way, it is possible to arrange guide elements 81 in the shaping 79 in the form of ring.

The exemplary embodiment shown in FIG. 23 shows, as an example of such guide elements 81, guide lugs placed in pairs on the ring-shaped conformation. These guide elements 81 slide during the machining process along the wall of the hole.

The exemplary embodiment shown in FIG. 24 again shows a support element 75 with a receiving cup active exclusively in the direction of the drill body 6. The ring-shaped configuration 79 is configured in this case as a flexing spring. To this end, in the ring-shaped conformation 79 a spring notch 82 is made. From the representation of FIG. 25, it can further be recognized that the guide elements 81 are inserted from the bit body 6 in the ring-shaped conformation 79. By virtue of its spring action, the ring-shaped conformation 79 is accommodated in the transverse direction 83 that extends transversely to the central axis 8 elastically in the drilling tool. The support element 75 is therefore configured as a flexing spring element.

Obviously, it is possible to transfer all the embodiments of Figures 21 to 24, as regards the configuration of the support element 75, related to the bit body 6, as a receiving cup in the same way also to the drill head 4. Configurations are also conceivable, in which a bilaterally active receiving cup overlaps not only the coupling side of the shank 70 of the drill body 6 but also a smaller area of ​​the coupling side 67 of the drill head 4.