Cleaning needle

Abstract

Broaching needle (10) for machining a workpiece (11) by broaching, with a shaft (12) extending along a longitudinal axis (20) and a plurality of cutting inserts (14) which can be detachably mounted on the shaft (12) so that, in an assembled state, they are lined up one behind the other along the longitudinal axis (20), wherein the shaft (12) has a cross-sectional shape which deviates from a circular-cylindrical shape in order to implement a rotation lock (19) of the cutting inserts (14).

Description

[0001] The present invention relates to a broach for machining a workpiece by broaching, comprising a shaft and a plurality of cutting inserts which can be detachably mounted on the shaft.

[0002] An exemplary broach is known from DE 44 22 573 A1.

[0003] Broaching is a machining process with a geometrically defined cutting edge. A broaching tool with multiple cutting edges, the so-called broach, is supported at two ends and guided along the workpiece to be machined (external broaching) or pulled through the workpiece to be machined through an existing through-hole (internal broaching). The guided movement of the broach is usually achieved by means of a broaching machine.

[0004] Through machining, a complementary shape to the broach is created on / in the workpiece. For example, broaches with rectangular outer contours are used to create grooves, and broaches with round outer contours are used to create round inner contours. Broaching round inner contours is often done in combination with the creation of internal gears by broaching.

[0005] The broach can be either a single-piece design or a modular structure with multiple interchangeable cutting inserts. Such interchangeable cutting inserts are often referred to as "cutting wheels" or "broaching wheels" in broaches.

[0006] A modular design advantageously enables the targeted replacement of worn (worn) cutting edges and is accompanied by increased flexibility in terms of cutting geometries, number of cutting edges, cutting shapes, etc.

[0007] However, the modular design of broaches has a negative impact on the dimensional accuracy and concentricity of the cutting edges, particularly due to the added dimensional tolerances of the various components. However, precise and reliable broaching requires precise alignment of the cutting edges. Especially for the production of internal gearing by broaching, the precise alignment of the individual cutting inserts is extremely important.

[0008] It is therefore an object of the present invention to provide a modular broach which enables precise alignment of the cutting inserts to one another and simple and cost-effective production.

[0009] This object is achieved according to the invention by a broach according to claim 1, which has a shaft extending along a longitudinal axis and a plurality of cutting inserts, wherein the cutting inserts can be detachably mounted on the shaft so that, in an assembled state, they are lined up one behind the other along the longitudinal axis, wherein the shaft has a cross-sectional shape deviating from a circular cylindrical shape in order to secure the cutting inserts against rotation.

[0010] According to the invention, the cutting inserts can be mounted on the shaft in a rotationally secure manner thanks to the cross-sectional shape of the shaft, which deviates from a circular cylindrical shape. This allows the cutting inserts to be precisely positioned on the shaft and aligned with each other. At the same time, the broach can be designed flexibly through the selection and / or arrangement (sequence) of the cutting inserts.

[0011] The above-mentioned task is thus completely solved.

[0012] According to one embodiment, a spacer element is arranged between two adjacent cutting inserts of the plurality of cutting inserts on the shaft.

[0013] The spacers can be used to adjust the distance between cutting inserts. The spacers can each have a chip chamber in their outer surface to store the chips removed from the workpiece during reaming.

[0014] The cutting inserts and their adjacent spacers are loosely connected to one another. Preferably, the cutting inserts and spacers are arranged alternately on the shaft. However, it is understood that multiple spacers can also be arranged between two cutting inserts.

[0015] According to a further embodiment, the spacer elements are each detachably or integrally connected to one of their two adjacent cutting inserts.

[0016] Each spacer element can thus be detachably attached to the adjacent cutting insert or formed integrally (monolithic) with the adjacent cutting insert. A detachable connection can positively impact the flexible design of the broach. A monolithic design, on the other hand, enables a highly stable design.

[0017] According to a further embodiment, a complementary shape to an outer contour of the shaft is formed to realize the anti-rotation device on the cutting inserts and / or the spacer elements.

[0018] To prevent rotation on the shaft, the cutting inserts and / or spacers are adapted to the outer contour of the shaft as counterparts and have a correspondingly adapted counter-shape to the shaft. Preferably, the connection between the shaft and the cutting inserts and / or spacers is designed as a fit.

[0019] According to a further embodiment, the complementary shape is formed at a through-opening of the cutting inserts and / or at a through-opening of the spacer elements.

[0020] The through-hole of the cutting inserts and / or the through-hole of the spacers thus has a complementary shape to the outer contour of the shaft. For assembly, the through-hole of the cutting inserts and / or the through-hole of the spacers are aligned relative to the outer contour of the shaft, and the cutting inserts and / or spacers are then pushed onto the shaft.

[0021] The cutting edges of the cutting inserts are preferably formed on the lateral surface of the cutting inserts.

[0022] According to a further embodiment, the complementary shape is formed on the spacer elements and the spacer elements are each connected to one of the two adjacent cutting inserts in a rotationally secure manner.

[0023] This advantageously simplifies the design of the cutting inserts. In particular, the cutting inserts do not need to have a complementary shape to the outer contour of the shaft in order to be rotationally aligned and secured around the longitudinal axis of the shaft when mounted on the shaft. This is particularly advantageous because the spacer elements are preferably made of comparatively easily deformable steel, while the cutting inserts are preferably made of hard metal. Furthermore, the assembly of the broach can be simplified by mounting the spacer element and the cutting insert, which is connected to the spacer element in a rotationally secure manner, together on the shaft.

[0024] The cutting inserts are connected to the adjacent spacer elements in a rotationally secure manner, preferably by means of a dowel pin and / or one or more screws.

[0025] According to a further embodiment, the spacer elements each have a centering device, in particular a conical section, wherein the centering device is designed to center one of the two adjacent cutting inserts of the respective spacer element with respect to the longitudinal axis.

[0026] This advantageously simplifies the design of the cutting inserts. In particular, the cutting inserts can be easily aligned concentrically with the respective spacer element and / or the shaft. When mounted on the shaft, the cutting inserts can also be aligned concentrically with the other cutting inserts using the centering devices of the spacer elements.

[0027] According to a preferred embodiment, the shaft has a polygonal cross-sectional shape, a star-shaped cross-sectional shape, a keyway or a cam to realize the anti-rotation device.

[0028] It is understood that further cross-sectional shapes and / or combinations of cross-sectional shapes are possible.

[0029] According to another embodiment, the cutting inserts are each ring-shaped.

[0030] In particular, the cutting inserts have a ring-shaped, closed surface so that they completely surround the shaft.

[0031] According to a further embodiment, the outer diameters of the cutting inserts increase along the longitudinal axis of the shaft from cutting insert to cutting insert.

[0032] The difference between the outer diameters of two adjacent cutting inserts (possibly with a spacer element between them) determines the chip thickness. This allows material to be removed continuously along the longitudinal axis of the shaft (and in the direction of movement of the broach).

[0033] According to a preferred embodiment, a first cutting insert of the cutting inserts has a first cutting geometry and a second cutting insert of the cutting inserts has a second cutting geometry which differs from the first cutting geometry.

[0034] The cutting geometries can vary along the longitudinal axis of the shaft. Cutting geometries specifically refer to the geometric arrangement of the cutting edges on a lateral surface of the cutting inserts or on an outer contour of the cutting inserts (e.g., for the same shape produced in the workpiece).

[0035] According to another embodiment, the broach needle has an axial locking device which axially secures the cutting inserts along the longitudinal axis of the shaft, wherein the axial locking device is detachably attachable to the shaft at a first free end of the shaft.

[0036] By attaching the axial locking device to the shaft, the cutting inserts (and, if applicable, the spacer elements) can be clamped so that they are held in a fixed position along the longitudinal axis of the shaft during broaching.

[0037] For example, the shaft has an external thread at the first free end, onto which an axial locking device with an internal thread can be screwed, so that pressure can be exerted on the cutting inserts (and, if applicable, the spacers) when screwed on. At the second free end of the shaft, the cutting inserts (and, if applicable, the spacers) can be secured axially along the longitudinal axis of the shaft, for example, by means of a locking element (e.g., a shaft shoulder).

[0038] According to a further embodiment, the shaft has a first shaft portion and a second shaft portion, wherein the first shaft portion is detachably attachable to the second shaft portion and is designed to secure the cutting inserts axially along the longitudinal axis of the shaft.

[0039] The first shaft section and the second shaft section can be aligned with each other, for example, by means of a centering fit formed on the first shaft section and / or on the second shaft section.

[0040] The first shaft section can also serve as an axial locking device. This reduces the number of broach components. By attaching the first shaft section to the second shaft section, the cutting inserts (and any spacers) can be clamped together, keeping them in a fixed position along the longitudinal axis of the shaft during broaching with the broach.

[0041] According to a preferred embodiment, the cutting inserts comprise hard metal and / or the spacer elements comprise steel and / or the shaft comprises steel.

[0042] Advantageously, the cutting inserts can be made entirely of carbide, which is characterized by good wear resistance. Preferably, the spacers and the shaft are also made of comparatively inexpensive steel. Accordingly, the material of the cutting inserts, spacers, and / or shaft can be tailored to their respective functions.

[0043] It is understood that the features mentioned above and those explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0044] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. They show: Fig. 1 a perspective view of a broach according to a first embodiment of the present invention in a disassembled state, together with a schematically indicated workpiece; Fig. 2 a sectional view of the Fig. 1 shown broach in an assembled state; Fig. 3 is a perspective view of a cutting insert belonging to the broach according to the first embodiment; Fig. 4 is a front view of a spacer element belonging to the broach according to the first embodiment; Fig. 5 a side view of the Fig. 4 shown spacer element; Fig. 6 a side view of the Fig. 3 shown cutting insert and the one in Fig. 4 and Fig. 5 shown spacer element in the assembled state; Fig. 7 a schematic representation to illustrate the contour of the cutting edges in the cutting direction of the broach; Fig. 8 is a sectional view of a broach according to a second embodiment of the present invention in the assembled state; Fig. 9 is a perspective view of a cutting insert belonging to the broach according to the second embodiment; Fig. 10 is a perspective view of a spacer element belonging to the broach according to the second embodiment; Fig. 11 is a perspective view of a broach according to a third embodiment of the present invention in a disassembled state; Fig. 12 a sectional view of the Fig. 11 shown broach in assembled condition; and Fig. 13 is a sectional view of a broach according to a fourth embodiment of the present invention in the assembled state.

[0045] Fig. 1 and Fig. 2 show a perspective view of a broach 10 in a partially assembled state and a sectional view of the broach 10 in an assembled state. In Fig. 1 also shows a purely schematic representation of a workpiece 11 to be machined with a through opening 13.

[0046] The broach 10 has a modular design and comprises a shaft 12, a plurality of cutting inserts 14, a plurality of spacer elements 16 and an axial lock 18, which axially secures the cutting inserts 14 and the spacer elements 16 on the shaft 12.

[0047] The shaft 12 is formed in one piece (integral, monolithic) and has a cross-sectional shape that deviates from a circular cylindrical shape, which can also be referred to as a "non-circular profile" and serves to realize an anti-rotation device 19. The shaft 12 extends along a longitudinal axis 20. An (external) thread 24 is formed near a first free end 22 of the shaft 12, and a shaft shoulder 28 is formed near a second free end 26 of the shaft 12 opposite the first free end 22. The shaft can be clamped into a broaching machine (not shown) at the first free end 22 and / or at the second free end 26, so that the broach can be guided during broaching by means of the broaching machine. The first free end 22 and the second free end 26 can thus serve as a clamping mandrel and a receiving mandrel, respectively.

[0048] The cutting insert 14 and the spacer element 16 are each substantially annular, with the cutting insert 14 having an outer diameter that is larger than an outer diameter of the spacer element 16. Cutting edges for machining a workpiece 11 are arranged on a lateral surface of the cutting insert 14.

[0049] In this embodiment, the axial locking device 18 is designed as a sleeve or nut. It has an internal thread 30 that corresponds to the external thread 24 formed on the shaft.

[0050] To assemble the broach 10, a cutting insert 14 and a spacer element 16 are alternately pushed onto the shaft 12 over the first free end 22 along the longitudinal axis 20 up to the shaft shoulder 28 (or a cutting insert 14 or spacer element 18 mounted in front of it). In the assembled state, the cutting inserts 14 and the spacer elements 16 are thus arranged alternately on the shaft 12, so that a spacer element 16 is arranged next to each cutting insert 14 on either side. After the cutting inserts 14 and the spacer elements 16 are mounted on the shaft 12, the axial lock 18 is screwed onto the external thread 24 of the shaft 12.

[0051] By means of the axial locking device 18, the cutting inserts 14 and the spacer elements 16 are placed under tension by pressing them against the shaft shoulder 28 of the shaft 12. Thus, the cutting inserts 14 and the spacer elements 16 are axially secured or fixed in position along the longitudinal axis 20 under complex loads that act particularly on the cutting inserts 14 during broaching operation.

[0052] To broach the workpiece 11, the fully assembled broach 10 can be pulled through the through hole 13 of the workpiece 11, for example by means of the broaching machine in which the first free end 22 and the second free end 26 are clamped.

[0053] Fig. 3-6 show the detailed structure of the cutting insert 14 ( Fig. 3) and the spacer element 16 ( Fig. 4 and Fig. 5), as well as the cutting insert 14 and the spacer element 16 in a detachably connected state ( Fig. 6).

[0054] Fig. Figure 3 shows a perspective view of the cutting insert 14 with a longitudinal axis 32 and a through-opening 33. A plurality of cutting edges 37 are formed on the lateral surface 35 of the cutting insert 14. The cutting edge 37, also referred to as a cutting tooth, has at least one cutting edge 60.

[0055] The cutting insert 14 has a plurality of receptacles 34 (referred to herein as "first receptacles"), which, in the assembled state of the broach 10, run parallel to the longitudinal axis 20 of the shaft 12 and are arranged on an end face 41 of the cutting insert 14. The receptacles 34 are arranged at regular intervals in the circumferential direction of the cutting insert 14. The receptacles 34 are each designed to receive a fastening means, such as a screw.

[0056] Furthermore, the cutting insert 14 has a receptacle 36 (referred to herein as the "second receptacle") arranged on the end face 41 between two first receptacles 34. In the assembled state of the broach 10, the receptacles 34, 36 are aligned parallel to the longitudinal axis 20 of the shaft 12. A dowel pin 62, which serves as a stop, is arranged in the second receptacle 36.

[0057] Fig. 4 and Fig. 5 show a perspective view and a side view of the spacer element 16. The spacer element 16 has a through-opening 39 that extends along a longitudinal axis 38 of the spacer element 16. A complementary shape to the outer contour of the shaft 12 is formed at the through-opening 39, which serves to implement the anti-rotation device 19. In other words, the inner contour of the through-opening 39 corresponds to the outer contour of the shaft 12.

[0058] The spacer element 16 has a plurality of receptacles 40 (referred to herein as “third receptacles”), a receptacle 42 (referred to herein as “fourth receptacle”) and a centering device 44.

[0059] In the assembled state of the broach 10, the third receptacles 40 extend parallel to the longitudinal axis 20 of the shaft 12 and are arranged at regular intervals on an end face 47 of the spacer element 16 in the circumferential direction of the spacer element 16. The third receptacles 40 are each designed to receive a fastening means (not shown here), such as a screw. They each have an internal thread.

[0060] The fourth receptacle 42 is arranged on the end face 47 of the spacer element 16 between two third receptacles 40 and, in the assembled state of the broach 10, also runs parallel to the longitudinal axis 20 of the shaft 12 or parallel to the third receptacles 40. The fourth receptacle 42 is designed to receive a fastening means such as a dowel pin 62.

[0061] The centering device 44 has in the Fig. 5 has a truncated cone which projects from the end face 47 of the spacer element 16 and is symmetrical to the longitudinal axis 38 of the spacer element 16.

[0062] Furthermore, the spacer element 16 has a chip chamber (not shown) formed on the outer surface of the spacer element 14 for storing the chips removed from the workpiece 11 during broaching. Particularly during internal broaching, the removed chips of the workpiece 11 cannot escape from the workpiece 11 during broaching. Thus, the chips must be stored until the broach 10 exits the workpiece 11, without the removed chips clogging the through-hole 13 of the workpiece 11 and the broach 10 becoming stuck in the workpiece 11.

[0063] Fig. 6 shows a side view of the cutting insert 14 in a state fastened to the spacer element 16, in which the cutting insert 14 is screwed to the spacer element 16 at the end. By means of the centering device 44, the second receptacle 36, the fourth receptacle 42 and a fastening means, such as the dowel pin 62, the cutting insert 14 can be precisely aligned with the spacer element 16. Since the spacer element 16 is in turn precisely aligned with the shaft 12 by means of the anti-rotation device 19, the cutting insert 14 is also aligned with the shaft 12 and secured against rotation. The plurality of cutting inserts 14 are thus very precisely aligned with one another and with the shaft 12.

[0064] For assembly, the cutting insert 14 is first pushed onto the centering device 44 of the spacer element 16. Using the centering device 44, the cutting insert 14 is aligned concentrically with the spacer element 16 so that the longitudinal axis 32 of the cutting insert 14 coincides with the longitudinal axis 38 of the spacer element 16.

[0065] The rotational alignment of the cutting insert 14 relative to the spacer element 16 about the longitudinal axis 32 of the cutting insert 14 or the longitudinal axis 38 of the spacer element 16 is carried out by means of the dowel pin 62, which is inserted into the second receptacle 36 of the cutting insert 14 ( Fig. 3) and into the fourth receptacle 43 of the spacer element 16 ( Fig. 4) is inserted. The locating pin 62 secures the cutting insert 14 to the spacer element 16 in a rotationally secure manner. Thus, the cutting insert 14 is aligned about the longitudinal axis 32 relative to the spacer element 16. The cutting edges 37 of the cutting insert 14 are thus aligned in a defined manner with the spacer element 16.

[0066] The dowel pin 62 acts as a poka-yoke element, so that incorrect assembly is avoided, which could result in the cutting edges 37 being incorrectly aligned with the spacer element 16 and thus with the shaft 12 or with cutting edges 37 of other cutting inserts 14.

[0067] At the same time, the dowel pin 62 aligns one of the first receptacles 34 ( Fig. 3) with one of the third shots 40 ( Fig. 4). A fastening means can be inserted into each of the aligned first receptacles 34 and third receptacles 40 in order to additionally fasten the cutting insert 14 to the spacer element 16. In the exemplary embodiment shown, four screws are each screwed through one of the first receptacles 34 into a thread provided in each of the third receptacles 40. Thus, in addition to the dowel pin 62, the cutting insert 14 is fastened to the spacer element 16 by means of the screws in a rotationally secure manner and is also secured in the axial direction. The corresponding threads are preferably provided in the first receptacles 34 and not in the third receptacles 40, since it is easier to introduce the threads into the spacer element 16 made of steel than into the cutting insert 14 made of hard metal.

[0068] The spacer element 16 can then be pushed onto the shaft 12 together with the cutting insert 14 attached to the spacer element 16 ( Fig. 1). In the assembled state, the longitudinal axis 20 of the shaft 12 coincides with the longitudinal axis 32 of the cutting insert 14 and the longitudinal axis 38 of the spacer element 16. The spacer element 16, and thus also the cutting insert 14 connected to it, is mounted on the shaft 12 in a rotationally secure manner about the longitudinal axis 20 by means of the anti-rotation device 19 (non-circular profile). The cutting inserts 14 are thus precisely aligned with the shaft 12 and with the other cutting inserts 14.

[0069] Despite the modular design of the broach 10, precise positioning of the cutting inserts 14 is thus ensured, particularly with regard to a concentric, rotationally aligned and torsion-proof arrangement around the longitudinal axis 20 of the shaft 12. Such precise positioning or alignment is very important, for example, when producing gear teeth by broaching.

[0070] The shaft 12 is made of steel, the cutting insert 14 of wear-resistant hard metal, and the spacer element 16 is also made of steel. This can have a beneficial effect on the production of the broach 10. The shaft 12 and the spacer element 16, which are subject to moderate (wear) loads, can be made of a comparatively inexpensive steel. The contour for the anti-rotation device 19 can thus be formed relatively easily on the shaft 12 and the spacer element 16. At the same time, the cutting insert 14 can be manufactured relatively easily from a comparatively expensive hard metal, which, although wear-resistant, is difficult to machine, so that the complementary shape to the outer contour of the shaft 12 in the cutting insert 14 would be complex (or expensive) to produce.However, production of the non-circular profile on the cutting insert 14 can advantageously be omitted, since in this embodiment it is formed on the spacer element 16.

[0071] Fig. Figure 7 shows an exemplary schematic sectional view of the cutting edges 37 of selected cutting inserts 14 in the cutting direction of the broach 10 (along the longitudinal axis 20 of the shaft 12). An outer diameter D of the cutting inserts 14 increases along the longitudinal axis 20 of the shaft 12 from cutting insert 14 to cutting insert 14. The difference in the outer diameters between two adjacent cutting inserts 14 determines the chip thickness removed from the workpiece 11 to be machined during broaching.

[0072] The cutting geometry of a first cutting insert 14, 43 (e.g. belonging to a first cut) differs from the cutting geometry of a second cutting insert 14, 45 (e.g. belonging to a last cut).

[0073] Fig. Figure 8 shows a sectional view of the broach 10 according to a second embodiment. In contrast to the first embodiment ( Fig. 1-7), the cutting insert 14, when mounted on the shaft 12, is loosely connected to the spacer element 16 and not fastened to the spacer element 16. Further deviating, the anti-rotation device 19 for the cutting inserts 14 is formed on the cutting insert 14 (and on the shaft 12) instead of on the spacer element 16.

[0074] Fig. 9 and Fig. 10 show a perspective view of the cutting insert 14 and the spacer element 16. The cutting insert 14 here has an inner contour that is complementary or corresponding to the outer contour of the shaft 12. The cutting insert is thus mounted on the shaft 12 in a rotationally secure manner (relative to the longitudinal axis 20). In principle, the spacer element 16 can also have an inner contour that is complementary or corresponding to the outer contour of the shaft 12. However, this is not absolutely necessary in this embodiment, since the cutting insert is already mounted on the shaft 12 in a rotationally secure manner. The cutting insert 14 and the spacer element 16 are, as mentioned, loosely connected to one another, i.e., not fastened to one another (e.g., by means of screws), so that the cutting insert 14 and the spacer element 16 do not have to be fastened to one another for the assembly of the broach 10.

[0075] If the spacer element 16 is not fixedly connected to the cutting insert 14, as is the case here, the spacer element 16 does not have to absorb any forces in the circumferential direction. Thus, alternatively, only the cutting insert 14 can have a complementary shape to the outer contour of the shaft 12 and be mounted in a rotationally secure manner, while the spacer element 16 can rotate about the longitudinal axis 20 of the shaft 12 during reaming operation.

[0076] Fig. 11 and Fig. 12 show a perspective view of the broach 10 in a partially assembled state and a sectional view of the broach 10 in another partially assembled state according to a third embodiment.

[0077] In contrast to the Fig. 1 and Fig. 2 and the first embodiment shown in Fig. In the second embodiment shown in Fig. 8, the shaft 12 is not formed in one piece, but has a first shaft section 46 and a second shaft section 48.

[0078] The first shaft section 46 has the first free end 22 and simultaneously functions as an axial lock 18. A free end 50 opposite the first free end 22 serves as a centering fit 52. An (internal) thread 54 is formed at this free end 50.

[0079] The second shaft section 48 has a cross-sectional shape that deviates from a circular cylindrical shape, which serves to implement the anti-rotation device 19. Furthermore, the second shaft section 48 has the second free end 26, on which the shaft shoulder 28 is arranged. At the end opposite the second free end 26, the second shaft section 48 has a fourth free end 56, on which an (external) thread 58 is formed and which serves as a centering fit 52.

[0080] In the Fig. 11, the cutting insert 14 and the spacer element 16 are in accordance with the embodiment shown in Fig. 3-7 shown first embodiment.

[0081] For the assembly of the broach 10, the spacer elements 16, to each of which a cutting insert 14 is attached ( Fig. 6) is pushed onto the second shaft section 48 from the fourth free end 56. At the second free end 26, the spacer element 16 and the cutting inserts 14 are secured in the axial direction by means of the shaft shoulder 28.

[0082] After the spacer elements 16 and the cutting inserts 14 have been pushed onto the second shaft section 48, the first shaft section 46 and the second shaft section 48 are aligned with each other by means of the centering fit 52 (also referred to as “guide fit”) and the thread 54 of the first shaft section 46 is screwed onto the thread 58 of the second shaft section 48.

[0083] The first shaft section 46 advantageously also functions as an axial lock 18, so that the number of components of the broach 10 is reduced.

[0084] When screwed on, the first shaft section 46 can exert a force on the mounted cutting inserts 14 and the mounted spacer elements 16, so that they are pressed against the shaft shoulder 28. Thus, the cutting inserts 14 and the spacer elements 16 can be held in a fixed position along the longitudinal axis 20 of the shaft 12 under complex loads that act particularly on the cutting inserts 14 during broaching operation.

[0085] Fig. 13 shows a sectional view of the broach 10 in a partially assembled state according to a fourth embodiment of the present invention. In contrast to the Fig. 11 and Fig. 12, the cutting inserts 14 and the spacer elements 16 are according to the second embodiment ( Fig. 9 and Fig. 10) trained.

[0086] It is understood that the exemplary embodiments shown in the figures merely represent exemplary configurations of the broach according to the invention, which are intended to illustrate the advantages of the broach according to the invention. Various modifications can be made to these exemplary embodiments without departing from the scope of the present invention. For example, the chip chambers can be formed on the cutting inserts and / or the spacer elements.

[0087] Furthermore, the cutting insert can be formed integrally (monolithic, one-piece) with the spacer element. The complementary shape to the outer contour of the shaft can also be formed on the cutting inserts and / or the spacer elements. Furthermore, spacer elements and cutting inserts can have different complementary shapes that partially correspond to the outer contour of the shaft. Furthermore, the cutting insert and the spacer element can have different numbers of first receptacles, second receptacles, third receptacles, and fourth receptacles. Furthermore, the centering device can also be formed on the cutting insert instead of on the spacer element. It is understood that the broach according to the invention can be used for internal and external broaching. List of reference symbols 10 broach 11 Workpiece 12 Wave 13 Through opening of the workpiece 14 cutting insert 16 spacer element 18 Axial locking 19 Anti-twist device 20 Longitudinal axis of the shaft 22 first free end 24 (external) thread 26 second free end 28 wave shoulder 30 (internal) thread 32 Longitudinal axis of the cutting insert 33 Through hole of the cutting insert 34 first recordings 35 Surface of the cutting insert 36 second shot 37 cutting edge 38 Longitudinal axis of the spacer element 39 Passage opening of the spacer element 40 third shots 41 Front side of the cutting insert 42 fourth recording 43 first cutting wheel 44 Centering device 45 second cutting wheel 46 first wave section 47 Front side of the spacer element 48 second wave section 50 third free end 52 Centering fit 54 (internal) thread 56 fourth free end 58 (external) thread 60 cutting edge 62 Dowel pin QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 44 22 573 A1

[0002]

Claims

[1] Broach (10) for machining a workpiece (11) by broaching, with a shaft (12) extending along a longitudinal axis (20) and a plurality of cutting inserts (14) which can be detachably mounted on the shaft (12) so that, in an assembled state, they are lined up one behind the other along the longitudinal axis (20), wherein the shaft (12) has a cross-sectional shape which deviates from a circular-cylindrical shape in order to implement a rotation lock (19) of the cutting inserts (14). [2] Broach needle (10) according to claim 1, wherein a spacer element (16) is arranged between two adjacent cutting inserts of the plurality of cutting inserts (14) on the shaft (12). [3] Broach (10) according to claim 2, wherein the spacer elements (16) are each detachably or integrally connected to one of their two adjacent cutting inserts (14). [4] Broach needle (10) according to claim 2 or 3, wherein a complementary shape to an outer contour of the shaft (12) is formed on the cutting inserts (14) and / or the spacer elements (16) to realize the anti-rotation device (19). [5] Broach needle (10) according to claim 4, wherein the complementary shape is formed on a through-opening (33) of the cutting inserts (14) and / or on a through-opening (39) of the spacer elements (16). [6] Broach (10) according to claim 4 or 5, wherein the complementary shape is formed on the spacer elements (16) and the spacer elements (16) are each connected to one of the two adjacent cutting inserts (14) in a rotationally secure manner. [7] Broach (10) according to one of claims 2 to 6, wherein the spacer elements (16) each have a centering device (44), in particular a conical section, wherein the centering device (44) is designed to center one of the two adjacent cutting inserts (14) of the respective spacer element (16) with respect to the longitudinal axis (20). [8] Broach needle (10) according to one of the preceding claims, wherein the shaft (12) has a polygonal cross-sectional shape, a star-shaped cross-sectional shape, a keyway or a cam for realizing the anti-rotation device (19). [9] Broach (10) according to one of the preceding claims, wherein the cutting inserts (14) are each annular. [10] Broach (10) according to one of the preceding claims, wherein outer diameters of the cutting inserts (14) increase along the longitudinal axis (20) of the shaft (12) from cutting insert (14) to cutting insert (14). [11] Broach (10) according to one of the preceding claims, wherein a first cutting insert (14, 43) of the cutting inserts (14) has a first cutting geometry and a second cutting insert (14, 45) of the cutting inserts (14) has a second cutting geometry which differs from the first cutting geometry. [12] Broach (10) according to one of the preceding claims, comprising an axial securing means (18) which secures the cutting inserts (14) axially along the longitudinal axis (20) of the shaft (12), wherein the axial securing means (18) is detachably attachable to the shaft (12) at a first free end (22) of the shaft (12). [13] Broach (10) according to one of the preceding claims, wherein the shaft (12) has a first shaft portion (46) and a second shaft portion (48), wherein the first shaft portion (46) is releasably attachable to the second shaft portion (48) and is adapted to secure the cutting inserts (14) axially along the longitudinal axis (20) of the shaft (12). [14] Broach (10) according to one of claims 2 to 13, wherein the cutting inserts (14) comprise hard metal and / or the spacer elements (16) comprise steel and / or the shaft (12) comprises steel.

Images