Rotary tool, in particular a drill for such a rotary tool

Abstract

The rotary tool comprises a support and a cutting head which can be inserted into a pin receptacle of the support via a coupling pin. The support and the cutting head have mutually corresponding surface sections for transferring a radial clamping force and have mutually corresponding torque sections for transferring torque. For an axial pull-out stop device, effective stop surfaces are formed on the pin receptacle and on the coupling pin in the axial direction, wherein, to do this, a stop element is formed, the radial extension of which is smaller than or equal to a radial extension (r.sub.2) of the surface sections of the coupling pin and wherein the stop surfaces and the surface section are offset relative to each other in the circumferential direction.

Claims

1. A rotary tool which extends along a rotational axis in the axial direction and has two coupling parts, comprising: a support the support having securing flanges at an end of the support and inner sheath surfaces that delimit a pin receptacle; and a cutting head interchangeably mounted on the support, the cutting head having a coupling pin inserted into the pin receptacle of the support so as to be clamped by rotating the cutting head relative to the support, wherein the coupling pin has outer sheath surfaces; wherein sheath sections corresponding to each other are formed on the inner sheath surfaces of the support and the outer sheath surfaces of the coupling pin for radial centering and for transmitting a radial clamping force; wherein mutually corresponding torque sections are formed on the cutting head and on the support for transmitting a torque; wherein stop surfaces are formed on the pin receptacle and on the coupling pin in the axial direction, the stop surfaces being formed by a stop element on the coupling pin; wherein the stop the stop element on the coupling pin has a first radial extension (r1) and the sheath sections of the coupling pin have a second radial extension (r2), the first radial extension being less than or equal to the second radial extension; and wherein the surface sections are offset relative to one another in the circumferential direction.

2. The rotary tool according to claim 1, wherein the stop element has a circular cross-sectional contour, excluding any recesses present due to the flutes.

3. The rotary tool according to claim 1, wherein the stop surfaces extend horizontally.

4. The rotary tool according to claim 1, wherein the stop surfaces are formed following the torque sections in the axial direction.

5. The rotary tool according to claim 1, wherein the stop surfaces are formed in an approximately triangular shape.

6. The rotary tool according to claim 1, wherein the stop element is formed at the end of the coupling pin.

7. The rotary tool according to claim 1, wherein additional torque sections corresponding to one another are designed on the inner sheath surfaces and on the outer sheath surfaces to transmit a torque.

8. The rotary tool according to claim 1, wherein the coupling pin has a substantially cuboid-shaped configuration in the region of the torque sections defining an elongated cross-sectional contour in the region of the torque sections.

9. The rotary tool according to claim 8, wherein the torque sections are formed by a longitudinal side of the cuboid-shaped configuration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An exemplary embodiment of the invention will be explained in more detail with reference to the figures. These show:

(2) FIG. 1 is a partial perspective view of a modular drill tool with cutting head and support shown in an exploded view,

(3) FIG. 2 shows a partial side view of the drilling tool in the area of the cutting head with cutting head inserted,

(4) FIG. 3A is a view of the back side of the cutting head,

(5) FIG. 3B is a side view of the cutting head of FIG. 3A after a rotation of 90 to the right of the view of FIG. 3A and

(6) FIG. 3C is another side view of the cutting head according to FIG. 3B after a 90 rotation about the rotational axis of the view of FIG. 3B,

(7) FIG. 4A, 4B show views of the support of the drilling tool, each rotated at 90 to each other around the axis of rotation

(8) FIG. 4C is a sectional view through the support along section line C-C of FIG. 4A, and

(9) FIG. 4D is a sectional view of the support along section line D-D of FIG. 4B.

(10) In the figures, parts that operate identically are represented by the same reference numerals.

DETAILED DESCRIPTION

(11) The rotary tool 2 shown in the figures is designed as a modular drilling tool. It extends in an axial direction 4 along a rotational axis 6. During normal operation, the rotary tool 2 rotates in the direction of rotation around the axis of rotation 6, which also defines a circumferential direction 8.

(12) The rotary tool 2 is composed of a support 10 and a cutting head 12 interchangeably mounted thereon. The cutting head 12 has cutting edges not illustrated here in detail which are usually connected to each other in the center on a drill end by means of a cross cutting edge and which extend radially outwardly. The main cutting edges join the face of the main flanks counter to the direction of rotation. On its circumferential side, the cutting head 12 has a back 14 which is interrupted by flutes 16 positioned opposite each other. These thus begin in the cutting head 12 and transition into the support 10. In the exemplary embodiment, the flutes 16 extend approximately helically. The support 10 has a grooved shaft section to which, for example, secondary cutting edges continue which begin at the cutting head 12 and extend along the flutes 16. An ungrooved clamping portion is typically joined onto the grooved shaft region of the support 10 with which the rotary tool 2 is clamped into a machining tool.

(13) Below, mutually corresponding elements on the support 10 are designated by the letter a and on the cutting head 12 are designated by the letter b.

(14) On its face, the support 10 has two approximately diagonally opposite securing flanges 18 which are interrupted by the flutes 16. The end faces of the securing flanges 18 are each bounded by planar end contact surfaces 22a, which are disposed within a common horizontal plane to which the rotational axis 6 is thus perpendicularly oriented.

(15) The pin receptacle 20 is circumferentially limited by inner circumferential surfaces 24a of the securing flanges 18. Furthermore, it is delimited on the bottom side by a bottom surface which runs horizontally, that is, perpendicular to the rotational axis 6. In addition, in a manner not shown here, coolant channels may run in the support 10 which exit in the bottom surface, for example, and are there aligned with corresponding coolant channels of the cutting head 12.

(16) On the inner sheath surfaces 24a, in each case the support 10 has torque sections 30a, clamping sections 32a and intermediate transition sections that join directly to one another in the circumferential direction 8.

(17) The cutting head 12 has a coupling pin 40 extending in the axial direction 4 corresponding to the pin receptacle 20. The coupling pin 40 is radially offset from the peripheral surfaces of the back 14. Corresponding to the pin receptacle 20, the coupling pin 40 has outer sheath sections 24b on which likewise are formed torque sections 30b, clamping sections 32b and intermediate transition sections. These join each other in each case in the circumferential direction 8, are preferably not staggered in the axial direction 4, and each is thus at the same axial height.

(18) A radial projection to the back 14 is formed by the radially set-back coupling pin 40 whereby two preferably horizontally extending head plate surfaces 22b are formed, which, in turn, are arranged in a common horizontal plane and are separated from each other by flutes 16. When mounted, the cutting head 12 lies thereon.

(19) In addition, an insertion pin may be formed on the coupling pin 40 concentric to the axis of rotation 6, this being designed only for initial centering of the cutting head 12 during insertion into the support 10. The actual centering of the cutting head 12 is accomplished by the clamping sections 32a, b.

(20) Of particular importance with respect to an axial pullout safety device is the fact that, in particular, a stop element 42 is arranged on the end of the coupling pin 40 that preferably defines somewhat triangular-shaped stop surfaces 38b on coupling pin 40. These extend in the horizontal direction, that is, perpendicular to the axis of rotation 6. They are located, in particular, immediately following the torque sections 30b in the axial direction 4. The torque sections 30b extend beyond a rounded edge into the abutment surfaces 38b. The stop element 42as is particularly clear in FIGS. 3A and 3Cis designed as a whole as a circular disk which is interrupted only in the area of the flutes 16. The stop element 42 in this case has a circular peripheral contour that is interrupted only by the flutes 16. In the axial direction, the stop element has a significantly more limited extension than the torque section 30b and the clamping section 32b.

(21) In this connection, the stop surfaces 38b preferably extend over an angular range which is at least approximately equal to the angular range over which the torque sections 30 extend.

(22) In the exemplary embodiment, the disc-shaped stop element 42, viewed in the circumferential direction 8, virtually extends into the clamping section 32b, thus aligning the outer surface of the stop element 42 with the outer surfaces of the clamping section 32b.

(23) As can be seen in particular from the side views of FIGS. 3B, 3C, the clamping section 32b and the torque sections 30b are arranged directly between the head surfaces 22b and the stop element 42, and extend to these via rounded edges. In the axial section area in which the torque sections 30b and the terminal sections 30a are formed, the coupling pin 40 has an overall cuboidal configuration, that is, an elongated cross-sectional contour. In this way, the longitudinal sides are rounded by the clamping sections 30b and front sides, having, for example, a cylindrically or even elliptically rounded shape, and define the clamping sections 32B.

(24) The pin receptacle 20 in the support 10, as is apparent from FIGS. 4A, 4B, 4C, 4D, is complementary on the whole to the coupling pin 40 of the cutting head 12. In the assembled state, the mutually corresponding clamping sections 32a, 32b and torque sections 30a, 30b in each case lie directly flat against one another. The flutes 16 continue into the cutting head 12 aligned by the support 10.

(25) As can be seen in particular from the top views shown in FIGS. 4A and 4B, in cross-section, the pin receptacle 20 has an approximately rectangular contour in the region of the clamping sections 32a and the torque sections 30a. From the top views of FIGS. 4A and 4B, the transition sections are also very clearly visible in the corner of the cuboid base geometry.

(26) A groove 44 corresponding to the stop element 42 is preferably formed in the support 10 immediately adjacent to the bottom surface. The groove 44 is designed in particular as a circular section groove. This means that the groove 44 corresponding to the stop element 42 forms lateral surfaces which extend along a circular arc, thus forming sections of a cylindrical sheath surface. The sheath surface of the cylinder, in turn, is preferably interrupted only by the flutes 16. In the exemplary embodiment, the cylindrical surface of the groove 44 is aligned with this in the clamping sections 32a (as viewed in the axial direction).

(27) Suitable triangular stop surfaces 38a are formed on the support 10 corresponding to the roughly triangular configuration of the stop surfaces 38b on the coupling pin 40. The torque sections 30a are formed in this peripheral region of the stop surfaces 38a. For this purpose, a portion of the support 10 which forms the torque sections 30a extends virtually radially inward beyond the groove 44 in the manner of an overhang (see FIG. 1, in particular).

(28) In the region of the torque sections 30a, b, therefore, a projection above the groove 44 is virtually formed, as can be seen particularly in FIG. 4C.

(29) At the same time, however, no overhang is formed in the clamping sections 32a. Rather, in the exemplary embodiment, the lateral surface of the groove 44 is aligned with the clamping section 32A. In this area, the support 10 thus has a continuous axially extending wall area. This means that in the exemplary embodiment a radial extension r.sub.1 of the stop element 42 and the groove 44 (see FIG. 3A in this connection and FIG. 4C) is identical to the radial extension r.sub.2 of the clamping sections 32a, 32b (for this, see FIG. 3B and FIG. 4B). Alternatively, the radial extension r.sub.1 of the stop element 42 is less than that of the clamping sections 32a, 32b.

(30) As is apparent in particular from the top view of the support according to FIG. 4A, the pin receptacle 20 and the corresponding coupling pin 40 in the region between the stop element 42 and head contact surface 22b have an essentially rectangular shape and thus an approximately block shape. Here, opposite corner regions of approximately rectangular cross-section are excluded by the flutes 16. The clamping sections 32a, b are formed on the narrow sides of this approximately rectangular cross-section, and the torque sections 30a, b are formed on the longitudinal sides.

(31) The torque sections 30a, b thus extend in a straight line, viewed in cross section, whereas the clamping sections 32a, b extend along an arc line, in particular a circular arc line. The corner areas of the approximately rectangular cross-section are rounded so that the rectilinear torque sections 30a merge into the rounded clamping sections 32a, b. In this way, the rounded corner areas are formed by the transitional sections.

(32) The section surfaces of the coupling pin 40 and the pin receptacle 20, that is, the torque sections 30a, b, the clamping sections 32a, b and the transitional sections, preferably run parallel to the rotational axis 6 and thus to the axial direction 4. They therefore have no angle of inclination, and do not form conical surfaces.

(33) To mount the cutting head 12, it is first plugged with its coupling pin 40 beforehand into the pin receptacle 20 in the axial direction 4. The entire cutting head 12 is then rotated within the pin receptacle 20 about the rotational axis 6 counter to the rotational direction. In this way, stop surfaces 38a, b engage behind. In addition, the clamping sections 32a, b form an interference fit and thus are clamped. In this way, a radial clamping force is applied by the securing flanges 18 onto the coupling pin 40 at the clamping sections 32a, b. In addition, the mutually corresponding torque sections 30a, b become attached to each other in the end position. In operation, the torque exerted in the torque and circumferential rotational direction 8 by the support 10 via the torque sections 30a, b is transmitted to the cutting head 12. In the mounted end position, the head bearing surfaces 22b lie flat on the end bearing surfaces 22a.

(34) A reliable axial pullout safety device is formed by the mutually corresponding, horizontally extending stop surfaces 38a, b. Expediently, in the process, a press fit is also formed when the coupling pin 40 is screwed into the pin receptacle 20, so that, at the same time, the coupling pin 40 is placed into the pin receptacle 20 in the axial direction 4 at a defined axial position. As an alternative to forming the interference fit in the area of the stop surfaces 38a, b, these may optionally lie against each other with slight play.