ROTARY TOOL, IN PARTICULAR A DRILL, AND A CUTTING HEAD FOR SAID ROTARY TOOL

Abstract

The rotary tool (2) is in particular designed as a modular drill and extends in an axial direction (4) along an axis of rotation (6). It comprises two coupling parts, namely a carrier (10) and a cutting head (12) that is attached to the carrier (10) so as to be exchangeable. A pin receiving means (20) is provided on the carrier (10), into which pin receiving means a coupling pin (40) of the cutting head (12) is introduced in a clamping manner and so as to be reversibly exchangeable. The pin receiving means (20) and the coupling pin (40) have torque sections (30a,b) and clamping sections (32a,b) that correspond to one another. In order to permit simple production, these clamping and torque sections are oriented parallel to the axis of rotation (6). In addition, in order to prevent pulling-out in an axial direction, stop surfaces (38a,b) are provided on the pin receiving means (20) and on the coupling pin (40), said stop surfaces being effective in an axial direction (4) and corresponding to one another. These stop surfaces preferably extend horizontally and therefore perpendicular to the axis of rotation (6).

Claims

1. A rotary tool (2), in particular a drill, which extends in an axial direction (4) along an axis of rotation (6) and comprises two coupling parts, namely a carrier (10) and a cutting head (12), and the cutting head (12) is attached to the carrier (10) so as to be exchangeable, wherein the carrier (10) comprises on its end surface fastening webs (18) with inner shell surfaces (24a) by means of which a pin receiving means (20) is delimited, in the pin receiving means (20), a coupling pin (40) of the cutting head (12) is introduced in a clamping manner by turning the cutting head (12) relative to the carrier (10), and the coupling pin (40) comprises outer shell surfaces (24b), on the inner shell surfaces (24a) and the outer shell surfaces (24b), torque sections (30a,b) corresponding to one another for transmitting a torque and clamping sections (32a,b) corresponding to one another for transmitting a radial clamping force are formed and respectively abut against one another in pairs, characterized in that the clamping sections (32a,b) and the torque sections (30a,b) extend parallel to the axis of rotation (6); and in that, in order to prevent a pulling-out in an axial direction, stop surfaces (38a,b) are formed on the pin receiving means (20) and on the coupling pin (40), said stop surfaces being effective in an axial direction (4).

2. The rotary tool (2) according to claim 1, characterized in that the stop surfaces (38a,b) extend horizontally and directly adjoin a torque section (30a,b) or a clamping section (32a,b) in an axial direction (4).

3. The rotary tool (2) according to claim 1 or 2, characterized in that an interference fit is formed between the corresponding stop surfaces (38a,b).

4. The rotary tool (2) according to any of the preceding claims, characterized in that the stop surfaces (38a,b) are formed on the one coupling part (10, 12) by means of a web (36b) extending in a circumferential direction (8).

5. The rotary tool (2) according to the preceding claim, characterized in that the stop surfaces (38a,b) extend in the circumferential direction (8) over the entire inner shell surfaces (24a) and outer shell surfaces (24b), or only over a partial area thereof.

6. The rotary tool (2) according to any of the preceding claims, characterized in that the clamping sections (32a,b) and the torque sections (30a,b) of the one coupling part, in particular the cutting head (12), are formed by a piercing.

7. The rotary tool (2) according to any of the preceding claims, characterized in that the coupling pin (40) is substantially cuboid, the clamping sections (32a,b) and the torque sections (30a,b) are formed on its circumferential sides.

8. The rotary tool (2) according to any of the preceding claims, characterized in that the clamping sections (32a,b) and the torque sections (30a,b) are arranged at the same axial height.

9. A cutting head (12) for a rotary tool (2) according to any of the preceding claims, the cutting head extending in an axial direction (4) along an axis of rotation (6) and comprising a coupling pin (40) with outer shell surfaces (24b) on which torque sections (30a,b) and clamping sections (32a,b) are formed, characterized in that the torque sections (30a,b) and the clamping sections (32a,b) extend parallel to the axis of rotation (6); and in that the coupling pin (40) furthermore comprises stop surfaces (38a,b) effective in an axial direction (4) in order to prevent a pulling-out in an axial direction.

10. The cutting head (12) according to claim 9, characterized in that the coupling pin (40) is substantially cuboid, on its circumferential sides the clamping sections (32a,b) or the torque sections (30a,b) or alternatively the stop surfaces (38a,b) are optionally formed by means of a piercing, and the stop surfaces (38a,b) are horizontally extending boundary surfaces of the piercing.

Description

DESCRIPTION OF FIGURES

[0031] An exemplary embodiment of the present invention is explained in greater detail below based on Figures. These show:

[0032] FIG. 1A a perspective illustration in section of a modular drill with cutting head and carrier, which are illustrated in the manner of an exploded view,

[0033] FIG. 1B the drill illustrated in section according to FIG. 1A, in a somewhat tilted exploded view compared to FIG. 1A,

[0034] FIG. 2A a top view of the bottom side of the cutting head according to FIGS. 1A, 1B,

[0035] FIG. 2B a lateral view of the cutting head according to FIG. 2A,

[0036] FIG. 2C another lateral view of the cutting head according to FIG. 2A, wherein the cutting head is rotated by 90 compared to FIG. 2B,

[0037] FIG. 3A a top view of the carrier according to FIG. 1A,

[0038] FIG. 3B a section view through the carrier according to FIG. 3A along the section line I-I,

[0039] FIG. 4A a top view of the carrier according to FIG. 1A, wherein the carrier is rotated by 90 compared to FIG. 3A and

[0040] FIG. 4B a section view through the carrier according to the section line II-II in FIG. 4A.

[0041] Parts having the same effect are given the same reference symbols in Figures.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0042] The rotary tool 2 illustrated in Figures is designed as a modular drilling tool. It extends in an axial direction 4 along an axis of rotation 6. The rotary tool 2 rotates about the axis of rotation 6 during normal operation in the direction of rotation, which at the same time defines a circumferential direction 8.

[0043] The rotary tool 2 is composed of a carrier 10 and a cutting head 12 that can be attached thereto so as to be exchangeable. The cutting head 12 comprises major cutting edges (not calculated [sic] here in more detail) which are usually connected centrally at a drill face to one another via cross-cutting edges and which extend radially outward. Against the direction of rotation, major free spaces adjoin the major cutting edges at the end surface. On its circumferential side, the cutting head 12 comprises a rear surface 14 which is interrupted by opposite flutes 16. Said flutes thus already start at the cutting head 12 and transition into the carrier 10. In the exemplary embodiment, the flutes 16 extend approximately helically. The carrier 10 is a grooved shaft section at which continue, for example, minor cutting edges which extend along the flutes 16 and start at the cutting head 12. A grooved shaft section of the carrier 10 is usually additionally adjoined by a non-grooved clamping section with which the rotary tool 2 is clamped in a machine tool.

[0044] Below, elements on the carrier 10 that correspond to one another are designated with the letter a and elements on the cutting head 12 that correspond to one another are designated with the letter b.

[0045] The carrier 10 comprises on its end surface two approximately diagonally opposite fastening webs 18 which are interrupted by flutes 16. The fastening webs 18 respectively extend over a range of approximately 70-90. The fastening webs 18 are respectively delimited at the end surface by planar end support surfaces 22a which are arranged in a common horizontal plane, with respect to which the axis of rotation 6 is thus oriented perpendicularly.

[0046] The pin receiving means 20 is delimited on the circumferential side by inner shell surfaces 24a of the fastening webs 18. Furthermore, it is delimited on the bottom side by a bottom surface which extends horizontally, i.e. perpendicular to the axis of rotation 6. In this bottom surface, a centering hole 26a is introduced concentrically to the axis of rotation 6. Furthermore, in exemplary embodiment 2, coolant channels 28 extend in the carrier 10, end in the bottom surface, and there are flush with corresponding coolant channels 28 of the cutting head 12.

[0047] At the inner shell surfaces 24a, the carrier 10 respectively comprises torque sections 30a, clamping sections 32a as well as transitional sections 34a which directly adjoin one another in the circumferential direction 8. Directly adjoining the bottom surface, grooves 36a are introduced into the inner shell surfaces 24a. Said grooves form horizontally extending stop surfaces 38a.

[0048] Corresponding to the pin receiving means 20, the cutting head 12 comprises a coupling pin 40 extending in an axial direction 4. The coupling pin 40 is radially set back in the radial direction from the circumferential surfaces of the rear surface 14. Corresponding to the pin receiving means 20, the coupling pin 40 comprises outer shell sections 24b on which torque sections 30b, clamping sections 32b, and transitional sections 24b are also formed. These sections respectively adjoin one another in the circumferential direction 8, are not arranged staggered in relation to one another in an axial direction 4, and are therefore respectively at the same axial height.

[0049] A radial projection toward the rear surface 14 is formed by means of the coupling pin 40 that is radially set back, whereby two head support surfaces 22b are formed which in turn are arranged in a common horizontal plane and separated from each other by the flutes 16.

[0050] Concentric to the axis of rotation 6, a lead-in pin 26b is furthermore formed on the coupling pin 40, said lead-in pin only being formed as a first centering aid for the cutting head 12 during introduction into the carrier 10. The actual centering of the cutting head 12 is carried out via the clamping sections 32a,b.

[0051] Furthermore, the coupling pin 40 respectively comprises webs 36b at its rear section facing away from the end surface of the cutting head 12, which webs 36b are respectively formed in the manner of ring segments and directly adjoin the clamping sections 32b. The webs 36b form stop surfaces 38b extending radially outward in the horizontal direction. Corresponding thereto, the grooves 36awhich are respectively also formed as annular groove segmentsare formed on the pin receiving means 20 in the area of the bottom. Said grooves also directly adjoin the torque section 30a.

[0052] On the sides of the coupling pin 40, the torque sections 30b and the clamping sections 32b are formed by means of a piercing so that these sections 30b, 32b and the transitional section 34b are formed by removing material. In this case, the piercing is made directly adjoining the head support surface 22b. In the transitional section, only a small curvature is provided. Accordingly, the sections 30a, 32a, 34a extend on the sides of the carrier 10 to the end support surface 22a, apart from an end surface lead-in chamfer.

[0053] In the exemplary embodiment, when viewed in the circumferential direction 8 the webs 36b and correspondingly the grooves 36a and accordingly the stop surfaces 38a,b extend over only a partial section of the fastening webs 18. They are respectively tapered off toward one of the two flutes 16 so that a screwing-in of the coupling pin 40 into the pin receiving means 20 is made possible.

[0054] The webs 36b and correspondingly the grooves 36a respectively comprise a shell surface which extends approximately parallel to the axis of rotation 6 and which is adjoined by a conical end section. The shell surfaces extend in an axial direction 4 over a comparatively short area in comparison to the axial extension of the sections 30a,b; 32a,b; 34a,b.

[0055] As can be seen in particular in the top views of the cutting head 12 according to FIG. 2A and the top views of the carrier 10 according to FIGS. 3A and 4A, the coupling pin 40 and the pin receiving means 20 have a substantially rectangular design and thus an approximately cuboid shape. In this case, however, opposite corner regions of the approximately rectangular cross-section are removed as a result of 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 long sides. As can be seen, the torque sections 30a,b extend linearly when viewed in cross-section, whereas the clamping sections 32a,b extend along an arc, in particular a circular arc. The corner regions of the approximately rectangular cross-section are rounded so that the linear torque section 30a transitions into the rounded clamping section 32a,b. The rounded corner regions are formed by transitional sections 34a,b.

[0056] The section surfaces of the coupling pin 40 and of the pin receiving means 20, namely the torque sections 30a,b, the clamping sections 32a,b, and the transitional sections 34a,b extend parallel to the axis of rotation 6 and thus to the axial direction 4. They therefore do not comprise an inclination angle and do not form any conical surfaces. In this way they can be formed simply, in particular by means of the already described piercing.

[0057] For mounting the cutting head 12, it is initially inserted in an axial direction 4 with its coupling pin 40 forward into the pin receiving means 20. Here, it is turned by approximately 90 compared to the position illustrated in FIGS. 1A and 1B. For this initial axial insertion, the lead-in pin 26b offers a first centering support. Subsequently, the entire cutting head 12 is turned against the direction of rotation around the axis of rotation 6 within the pin receiving means 20. In doing so, the webs 36b engage behind the grooves 36a. Additionally, the clamping sections 32a,b form an interference fit and thus a clamping relationship. In the process, a radial clamping force is exerted by the fastening webs 18 at the clamping sections 32a,b on the coupling pin 40. In the final position, the torque sections 30a,b corresponding to one another furthermore come into contact with each other. During operation, the torque exerted by the carrier 10 is transmitted via the torque sections 30a,b in the direction of rotation and circumferential direction 8 to the cutting head 12. In the mounted final position, the head support surfaces 22b rest flat on the end support surfaces 22a.

[0058] Via the horizontally extending stop surfaces 38a,b corresponding to one another, a reliable axial pull-out lock is formed by the engaging of the webs 36b behind the grooves 36a. Expediently, an interference fit is also formed therewith so thatwhen the coupling pin 40 is screwed into the pin receiving means 20the coupling pin 40 is also at the same time brought in the axial direction 4 into a defined axial position in the pin receiving means 20.

[0059] For this purpose, a small lead-in chamfer is preferably arranged on the grooves 36a and the webs 36b. As an alternative to forming the interference fit in the area of the stop surfaces 38a,b, said stop surfaces possibly abut against each other with a small clearance.