Reamer for machining a workpiece

Abstract

The invention relates to a reamer (1) comprising: - a tool body (3), which has a central axis (5) around which a circumferential direction runs, and an effective end (11) with an expansion recess (13) on the end face, wherein an expansion element (15) is positioned in the expansion recess (13) so as to be displaceable along the central axis (5); - an imaginary first tool body sector (7.1) of the tool body (3), said first tool body sector extending in regions along the circumferential direction and along the central axis (5) and having at least one cutting edge (17) positioned in it, which is positioned at the effective end (11) of the tool body (3); - an imaginary second tool body sector (7.2) which is different from the first tool body sector (7.1), extends in regions along the circumferential direction and along the central axis (5) and in which at least two support elements (19) are positioned, which are spaced apart from one another in the circumferential direction at the effective end (11) of the tool body (3), wherein - the first tool body sector (7.1) and the second tool body sector (7.2) are free of overlap, and - a displacement device (9) which is configured to displace the expansion element (15) along the central axis (5) in order to widen the tool body (3) at the effective end (11) so as to change a cutting circle diameter, running around the central axis (5), of the at least one cutting edge (17).

Description

[0001] DESCRIPTION

[0002] Reamer for machining a workpiece

[0003] The invention relates to a reamer for machining a workpiece by removing material.

[0004] Such a reamer is known from CZ 308960 B6. The reamer has a reaming element that can be removed from the tool body. The reaming element forms three grouped cutting edges and, offset circumferentially, three grouped support surfaces, with the reaming element, the three cutting edges, and the three support surfaces being formed as a single piece. To introduce a cutting torque into the end element, the end element has a drive groove. The drive groove is located opposite a central cutting edge and between two support surfaces. Depending on the internal diameter to be produced, an unsuitable end element, which has cutting edges with an unsuitable cutting circle diameter, can be removed from the tool body and a suitable reaming element, which has cutting edges with a suitable cutting circle diameter, can be mounted.

[0005] A disadvantage of this concept is the limited selection of possible internal diameters, as only those internal diameters can be produced for which there is an end element with precisely matched cutting edges and support surfaces, specifically ground, that precisely match the target cutting circle diameter. Furthermore, it is not possible to correct an actual cutting circle diameter that deviates from the target diameter – either before or during machining – for example, if the cutting edges are worn. Since the drive groove is located opposite a cutting edge, producing, and inspecting, especially measuring, a highly accurate cutting circle diameter on the cutting edges is comparatively complex and requires significant effort.

[0006] The invention is therefore based on the objective of creating a reamer for machining a workpiece, whereby the aforementioned disadvantages are at least reduced, and preferably avoided. This objective is achieved by providing the present technical teaching, in particular the teaching of the independent claims as well as the embodiments disclosed in the dependent claims and the description.

[0007] The problem is solved in particular by creating a reamer for machining a workpiece, comprising a tool body with a central axis, an imaginary first tool body sector extending partially along a circumferential direction encompassing the central axis and along the central axis, an imaginary second tool body sector distinct from the first tool body sector and extending partially along the circumferential direction and along the central axis, and a displacement device. The tool body further comprises an active end with an expansion recess on its face. An expansion element is displaceably arranged in the expansion recess along the central axis. At least one cutting edge is arranged in the first tool body sector. This at least one cutting edge is also arranged at the active end of the tool body.In the second tool body sector, at least two support elements are arranged. These at least two support elements are further spaced apart from each other in the circumferential direction at the working end of the tool body. The first and second tool body sectors are arranged without overlap, in particular without overlapping with each other. The displacement device is configured to displace the expansion element along the central axis in order to, in particular, expand the tool body at the working end, in order to, in particular, change the cutting circle diameter of the at least one cutting edge that encompasses the central axis.

[0008] Advantageously, the time-consuming replacement of the end element can be avoided. Furthermore, by expanding the tool body, the reamer's cutting circle diameter can be set with exceptional precision, particularly in the micrometer range. The cutting circle diameter can also be adjusted in comparatively very small increments, particularly steplessly, continuously, or continuously. It is also possible to correct an actual cutting circle diameter that deviates from the target diameter and is too small by forcing the expansion element into the tool body, thereby increasing the actual cutting circle diameter to the target diameter.Furthermore, it is possible to compensate for wear on at least one cutting edge, in particular by widening the flying circle diameter by a wear difference value, wherein the wear difference value specifically quantifies by what value the flying circle diameter is smaller with a worn cutting edge than with a non-worn, in particular new, cutting edge.

[0009] In the context of this technical teaching, a tool body sector, selected from the first tool body sector and the second tool body sector, is understood to be, in particular, a tool body volume formed, and especially bounded, by conceptually extruding a circular sector along the central axis to a specified extrusion length. The circular sector lies, in particular, in a plane perpendicular to the central axis of the reamer. Specifically, the extrusion length is freely selectable. Thus, the height of a tool body sector, selected from the first tool body sector and the second tool body sector, along the central axis is also freely selectable. Specifically, a tool body sector, selected from the first tool body sector and the second tool body sector, extends along a segment of the central axis.

[0010] In one embodiment, the at least one tool body sector extends from the working end along the central axis towards a shaft end, in particular a clamping end, of the reamer.

[0011] In one embodiment, the extrusion length of a tool body sector, selected from the first tool body sector and the second tool body sector, corresponds to an axial extent of an element selected from the at least one cutting edge and the at least two support elements. In particular, both tool body sectors have the same extrusion length.

[0012] In one embodiment, the first tool body sector is formed, in particular limited, by an effective end side of the at least one cutting edge facing the workpiece and a clamping end side of the at least one cutting edge opposite the effective end side and facing away from the workpiece.

[0013] In one embodiment, the second tool body sector is formed, and in particular limited, by an effective end side of the at least two support elements facing the workpiece and a clamping end side of the at least two support elements opposite the effective end side and facing away from the workpiece. In another embodiment, the first tool body sector and the second tool body sector are arranged at the same axial height in certain areas along the central axis.

[0014] In one embodiment, the first tool body sector extends further along the central axis towards the working end than the second tool body sector. Specifically, the first tool body sector extends along the central axis towards the working end beyond the second tool body sector. This is particularly because the at least one cutting edge projects from the tool body along the central axis towards the working end, while the support element does not project from the tool body along the central axis towards the working end. In this case, a tool body sector is understood to encompass not only the tool body volume up to an end face of the tool body facing the workpiece and oriented transversely on the central axis, but also the volume up to the working end face of the at least one cutting edge projecting from the tool body, which is located outside the tool body along the central axis.

[0015] The term "working end" refers in particular to the end of the tool body of the reamer that is intended to face the workpiece being machined. The term "shank end" refers in particular to the end of the tool that is intended to face away from the workpiece being machined and that lies opposite the working end along the central axis. In a preferred embodiment, the shank end is designed to be connected to a machine tool, an adapter, or the like. In particular, the shank end can be the clamping end or a clamping shank of the tool. "Extension towards the shank end" means in particular that the element so designated extends in the direction of the shank end; the element need not necessarily reach the shank end but can instead terminate at a distance from it.

[0016] In particular, the first tool body sector and the second tool body sector are arranged circumferentially offset from one another, especially such that the first tool body sector and the second tool body sector do not overlap, even partially. In particular, the first tool body sector and the second tool body sector are arranged adjacent to one another, especially directly or indirectly.

[0017] In the context of this technical teaching, the fact that a cutting edge is arranged in the first tool body sector means, in particular, that a cutting edge of the cutting edge, especially completely, is arranged in the first tool body sector. In particular, the cutting edge itself is also arranged completely in the first tool body sector. However, it is also possible that the cutting edge is not necessarily arranged completely in the first tool body sector. This is to be understood, in particular, as meaning that while the cutting edge is arranged in the first tool body sector, a back section of the cutting edge opposite the cutting edge is not arranged in the first tool body sector.

[0018] In the context of the present technical teaching, the fact that at least two support elements are arranged in the second tool body sector means, in particular, that one support element center, especially with respect to a circumferential direction, is arranged, and in particular completely, in the second tool body sector. In particular, the at least two support elements are also arranged completely in the second tool body sector.

[0019] In one embodiment, the reamer has exactly one and only one first tool body sector. In particular, the reamer has exactly one and only one second tool body sector.

[0020] In one embodiment, all support elements of the reamer are arranged in the same second tool body sector. In particular, the reamer has exactly one single second tool body sector. In particular, all cutting edges of the reamer are arranged in the same first tool body sector. In particular, the reamer has exactly one single first tool body sector. Advantageously, the reamer thus has an asymmetrical distribution of the cutting edges and the support elements—with the cutting edges in the first tool body sector and the support elements in the second tool body sector—which allows for the production of a particularly precise surface on a workpiece.

[0021] In one embodiment, the first tool body sector is free of support elements, so that in particular no support elements are arranged in the first tool body sector. In particular, the only first tool body sector is free of support elements, so that in particular no support elements are arranged in the only first tool body sector. In particular, no first tool body sector of the reamer has one or more support elements.

[0022] In one embodiment, the second tool body sector is free of cutting edges, so that in particular no cutting edges are arranged in the second tool body sector. In particular, the only second tool body sector is free of cutting edges, so that in particular no cutting edges are arranged in the only second tool body sector. In particular, no second tool body sector of the reamer has one or more cutting edges.

[0023] An axial direction extends, in particular, along the central axis of the reamer, especially in the feed direction of the reamer relative to a workpiece being machined by the reamer. Preferably, the axial direction corresponds to an axis of rotation of the reamer if the reamer is rotated to machine the workpiece. However, it is also possible that the workpiece is rotated while the reamer is held stationary or additionally rotated relative to the workpiece. In this case, the axial direction preferably coincides with the axis of rotation of the workpiece. A radial direction is perpendicular to the axial direction, in particular the central axis. A circumferential direction encompasses the axial direction, in particular the central axis, concentrically.

[0024] In one embodiment, the expansion recess is formed section by section as a cylindrical recess, in particular as a bore extending along the central axis. The expansion recess particularly has a thread. Additionally, the expansion recess particularly has a displacement section against which the expansion element rests and along which the expansion element can be displaced. The thread particularly has a diameter that is smaller than the diameter of the displacement section. In particular, the expansion recess is formed as a stepped bore. In particular, the thread adjoins the cylindrical recess. In particular, the expansion recess is section by section conically formed towards the effective end, thus in particular having a chamfer, which is formed in particular at an edge between the end face of the tool body and a cylindrical surface of the expansion recess.In one embodiment, the expansion element—when arranged as intended in the expansion recess—has a shape rotationally symmetrical about the central axis. In particular, the expansion element is frustoconical, specifically such that it is arranged with a smaller diameter end in the expansion recess, particularly so that it is inserted into the recess first. The expansion element further features, in particular, a through-opening extending along the central axis with a contact collar. In particular, the contact collar has a contact surface oriented transversely to the central axis.

[0025] In one embodiment, the displacement device comprises a screw element. The screw element extends, in particular, through the through-opening of the expansion element and rests with a screw head, specifically with a counter-contact surface of the screw head oriented transversely to the central axis, against the contact collar of the through-opening, specifically against the contact surface of the contact collar. The screw element further engages, in particular, in the thread of the expansion recess. Specifically, by screwing the screw element into the thread, the expansion element is displaced along the central axis and forced into the expansion recess. In this process, the tool body is expanded at the working end, particularly due to the frustoconical shape of the expansion element.

[0026] In one embodiment, the screw element has a retaining element that surrounds the screw element – ​​particularly along its central axis when arranged as intended. Specifically, the expansion element is arranged – along the central axis – between the retaining element and the screw head, in particular such that the expansion element is displaced, and especially pushed out, of the expansion recess, particularly along its central axis, when the screw element is unscrewed from the thread.

[0027] In one embodiment, the at least one cutting edge is a separate element from the tool body, which is attached to the tool body, in particular soldered to it. In particular, the at least one cutting edge is designed as a cutting element, especially as a cutting plate. In particular, the tool body has at least one cutting edge recess into which the at least one cutting element can be inserted and to which the at least one cutting element can be attached.

[0028] In one embodiment, the at least one cutting edge has a radial cutting section and, in particular, an axial cutting section. The radial cutting section projects, in particular, radially, and especially transversely to the central axis, from the tool body, while the axial cutting section projects, in particular, axially, and especially along the central axis, from the end face of the tool body at the working end. The radial cutting section is oriented approximately parallel, and in particular parallel to, the central axis. The axial cutting section is oriented approximately transversely, and in particular transversely to, the central axis. The radial cutting section transitions into the axial cutting section via a chamfer.

[0029] According to a further development of the invention, it is provided that a cutting edge of the at least one cutting edge and a support element, in particular a support element located at the rear in the cutting direction of rotation, of which at least two support elements are assigned to each other and opposite each other with respect to the central axis, in particular diametrically opposite each other.

[0030] The diametrically opposed arrangement, in particular, has the advantage that it is relatively easy to produce, especially by grinding, and to test, especially by measuring, a highly accurate flying circle diameter for the cutting edges. The at least one cutting edge and the at least two support elements can be ground simply, not twice, especially in a single grinding operation, which advantageously results in a highly accurate flying circle diameter.

[0031] In one embodiment, a cutting edge of a cutting edge of the at least one cutting edge and a support element center of the support element rearward in the cutting direction of rotation of the at least two support elements are assigned to each other and arranged opposite each other with respect to the central axis, in particular diametrically opposite each other.

[0032] According to a further development of the invention, the reamer has at least two cutting edges arranged at a distance from each other in the circumferential direction. This advantageously increases the efficiency of the reamer. In particular, machining time can be reduced because a higher material removal rate is possible with the reamer.

[0033] According to a further development of the invention, it is provided that a first cutting edge, in particular a first radial cutting section, of a first cutting edge of the at least one cutting edge and a second cutting edge, in particular a second radial cutting section, of a second cutting edge of the at least one cutting edge are arranged offset from each other along the central axis.

[0034] In one embodiment, the first cutting edge is a leading cutting edge with a leading cutting edge, in particular a leading radial cutting section, wherein the second cutting edge is a trailing cutting edge with a trailing cutting edge, in particular a trailing radial cutting section.

[0035] In particular, the circumferential arrangement of the cutting edges is uneven, as the cutting edges of at least one cutting edge are only located in the first sector of the tool body. This leads, in particular, to the leading cutting edge and the trailing cutting edge removing different amounts of workpiece material per revolution of the reamer. This is especially true because the trailing cutting edge, particularly the trailing radial cutting section, does not engage with the workpiece like the leading cutting edge, particularly the leading radial cutting section, since the workpiece material has already been removed by the leading cutting edge, particularly the leading radial cutting section.This effect can be reduced, and in particular avoided, by offsetting the cutting edges, especially the radial cutting sections, relative to each other along the central axis, so that the leading and lagging cutting edges remove approximately the same amount of material, or even the same amount. This is achieved in particular by having the lagging cutting edge project further from the tool body along the central axis than the leading cutting edge.

[0036] In particular, the leading cutting edge, especially the leading radial cutting section, projects from the tool body by a first distance, particularly a small one, along the central axis, and the lagging cutting edge, especially the lagging radial cutting section, projects from the tool body by a second distance, particularly a large one, along the central axis. In particular, the second distance is greater than the first distance.

[0037] The fact that the trailing cutting edge projects further from the tool body along the central axis than the leading cutting edge does not necessarily mean, in the context of the present technical teaching, that a trailing cutting element forming the trailing cutting edge projects further from the tool body along the central axis than a leading cutting element forming the leading cutting edge. The offset along the central axis can also be achieved, in particular, by having the leading cutting edge, especially the leading radial cutting section, and the trailing cutting edge, especially the trailing radial cutting section, originate at different axial positions along the central axis, particularly starting from the effective end face associated with the cutting element.In particular, the leading cutting element and the lagging cutting element terminate along the central axis in the direction of the effective end in the same plane oriented transversely to the central axis, and thus project the same distance from the tool body along the central axis. Specifically, a leading axial cutting section of the leading cutting edge and a lagging axial cutting section of the lagging cutting edge are located in the same plane oriented transversely to the central axis.

[0038] In particular, the leading cutting element has a leading cutting edge chamfer than the cutting edge chamfer, and the trailing cutting element has a trailing cutting edge chamfer than the cutting edge chamfer. In particular, the leading cutting edge chamfer is designed and arranged such that it results in the first gap. In particular, the trailing cutting edge chamfer is designed and arranged such that it results in the second gap.

[0039] This advantageously leads to uniform wear on the cutting edges, especially the radial cutting sections, and to uniform chip formation.

[0040] In one embodiment – ​​where the reamer additionally has a third cutting edge trailing the second cutting edge, with a third cutting edge, in particular a third radial cutting section – the third cutting edge projects from the tool body by a third, in particular a maximum, distance along the central axis. In particular, a third chamfer of the third cutting edge is designed and arranged such that this results in the third distance. In particular, the third distance is greater than the second distance. In particular, the second distance corresponds approximately to half, in particular exactly to half, of the sum of the first distance and the third distance.

[0041] In particular, the first cutting edge is arranged on a first axial position along the central axis, wherein the second cutting edge is arranged section by section on a second axial position along the central axis, which differs from the first axial position. Specifically, a first radial cutting section of the first cutting edge is arranged on the first axial position along the central axis, and a second radial cutting section of the second cutting edge is arranged section by section on the second axial position along the central axis, which differs from the first axial position.

[0042] According to a further development of the invention, the reamer has exactly three cutting edges as its at least one cutting edge, which are spaced apart from one another in the circumferential direction. The reamer has exactly three support elements as its at least two support elements. This represents a particularly advantageous embodiment, since the reamer is comparatively efficient, thus enabling a comparatively high material removal rate, while at the same time the quality, and in particular the accuracy, of the surface produced is comparatively high and is not impaired by the high material removal rate.

[0043] In one embodiment, the reamer has exactly three cutting edges as its at least one cutting edge, wherein the reamer has at least two support elements.

[0044] In one embodiment, the reamer has exactly three support elements as the at least two support elements, wherein the reamer has at least one cutting edge.

[0045] In one embodiment, the at least two cutting edges, in particular the exactly three cutting edges, are arranged in the same first tool body sector. In particular, the reamer has exactly one single first tool body sector. In particular, the at least two cutting edges, in particular the exactly three cutting edges, are arranged in this exactly single first tool body sector.

[0046] In one embodiment, the at least two support elements, in particular the exactly three support elements, are arranged in the same second tool body sector. In particular, the reamer has exactly one single second tool body sector. In particular, the at least two support elements, in particular the exactly three support elements, are arranged in this exactly single second tool body sector.

[0047] Advantageously, even in these embodiments, the reamer has an asymmetrical distribution of the cutting edges and support elements - with one or more cutting edges in the first tool body sector and the support elements in the second tool body sector - which also has the advantage that a particularly precise surface can be produced.

[0048] In one embodiment, the reamer has exactly three cutting edges: the front cutting edge (in the cutting direction), the middle cutting edge (in the cutting direction), and the rear cutting edge (in the cutting direction). In particular, the front cutting edge precedes the middle cutting edge, especially immediately. In particular, the middle cutting edge precedes the rear cutting edge, especially immediately. In particular, the second tool body sector is arranged between the front cutting edge and the rear cutting edge in the cutting direction.

[0049] In one embodiment, the reamer has exactly three support elements: a front support element in the cutting direction, a middle support element in the cutting direction, and a rear support element in the cutting direction. In particular, the front support element precedes the middle support element, especially immediately. In particular, the middle support element precedes the rear support element, especially immediately. In particular, the first tool body sector is arranged between the front support element and the rear support element in the cutting direction.

[0050] In one embodiment, the pre-cutting angle between the leading edge of the three cutting edges (in the cutting direction) and the middle edge of the three cutting edges (in the cutting direction) is 60° to 80°, particularly 65° to 75°. In particular, the post-cutting angle between the trailing edge of the three cutting edges (in the cutting direction) and the middle edge of the three cutting edges (in the cutting direction) is 60° to 80°, particularly 65° to 75°.

[0051] In one embodiment, the pre-support angle between the front support element of the three support elements (in the cutting direction) and the middle support element of the three support elements (in the cutting direction) is 40° to 80°, in particular 45° to 75°, or in particular 45° to 55°, or 55° to 65°, or 65° to 75°. In particular, the post-support angle between the rear support element of the three support elements (in the cutting direction) and the middle support element of the three support elements (in the cutting direction) is 40° to 70°, in particular 45° to 65°, or in particular 45° to 55°, or 55° to 65°. In a preferred embodiment, the pre-cutting angle and the post-cutting angle are each 65° to 75°, wherein the pre-support angle and the post-support angle are each 45° to 55°.

[0052] In another preferred embodiment, the pre-cutting angle and the post-cutting angle are each from 65° to 75°, wherein the pre-support angle is from 65° to 75° and the post-support angle is from 55° to 65°.

[0053] According to a further development of the invention, it is provided that one cutting edge of the three cutting edges and one support element of the three support elements are assigned to each other and are arranged opposite each other with respect to the central axis, in particular diametrically opposite each other.

[0054] The diametrically opposed arrangement, in particular, offers the advantage, even with three cutting edges, that it is relatively easy to produce a highly accurate trajectory diameter, especially by grinding, and to test and measure it. The three cutting edges and the three support elements can be ground simply, not twice, and especially in a single grinding operation, resulting advantageously in a highly accurate trajectory diameter.

[0055] In one embodiment, a cutting edge of the cutting edge and a support element center of the support element are arranged opposite each other, in particular diametrically opposite each other, with respect to the central axis.

[0056] In one embodiment - if the reamer has exactly three cutting edges and exactly three support elements - the middle cutting edge of the three cutting edges, in particular their cutting edge, is arranged in the circumferential direction opposite, in particular diametrically opposite, the middle support element of the three support elements in the circumferential direction, in particular its support element center, with reference to the central axis.

[0057] In particular, a first alignment angle between the cutting edge at the front in the cutting direction and the support element at the front in the cutting direction, viewed from the cutting edge in the cutting direction, is between 155° and 185°, in particular less than 185°, in particular less than 180°, in particular less than 175°, in particular less than 170°, in particular less than 165°. In particular, a second alignment angle between the cutting edge at the center in the cutting direction and the support element at the center in the cutting direction, viewed from the cutting edge in the cutting direction, is between 175° and 185°, in particular 180°, in particular exactly 180°.

[0058] In particular, a third alignment angle between the cutting edge located at the rear in the cutting direction and the support element located at the rear in the cutting direction, viewed from the cutting edge in the cutting direction, is from 185° to 205°, in particular less than 205°, in particular less than 200°, in particular less than 195°, in particular less than 190°.

[0059] According to a further development of the invention, the expansion recess has a varying wall thickness in the circumferential direction such that the diameter of the flight circle and the diameter of a support circle of the at least two support elements are changed differently during expansion, in particular during displacement, especially during the insertion of the expansion element. In particular, a wall having the specified wall thickness is formed by the tool body.

[0060] In one embodiment, the cutting circle diameter is increased more than the support circle diameter during expansion, particularly displacement, and especially the insertion of the expansion element. Specifically, the cutting circle diameter, and optionally the support circle diameter, is increased to such an extent that the cutting circle diameter, particularly in absolute terms, is larger than the support circle diameter. This has the particular advantage that the probability of the reamer becoming stuck, or jammed, in a workpiece, especially in a bore in the workpiece, is significantly reduced, preferably virtually eliminated.

[0061] In one embodiment, the flying circle diameter is expanded by up to 0.2% compared to an unexpanded flying circle diameter, particularly when the expansion element is not inserted into the expansion recess. Specifically, the support circle diameter is expanded by up to 0.06% compared to an unexpanded support circle diameter, particularly when the expansion element is not inserted into the expansion recess. In particular, the differential expansion results in a radial first cutting edge projection. The radial first cutting edge projection is, in particular, a value of a radial first projection, specifically a first radius difference value, between the flying circle diameter and the support circle diameter. Specifically, the cutting edge projects beyond the support circle diameter, in particular by the first radius difference value.

[0062] In one embodiment, the tool body has at least one chip space, in particular one chip space per cutting edge, and in particular, three chip spaces in the case of three cutting edges. In particular, each cutting edge is assigned its own chip space, wherein the respective chip space immediately precedes the assigned cutting edge.

[0063] In particular, the chip spaces create the varying wall thickness, especially because, due to the chip spaces, the wall thickness of the tool body in a chip space angle area encompassing the central axis, in which a chip space is arranged, is less than the wall thickness in a chip space-free angle area, in which no chip space is arranged.

[0064] According to a further development of the invention, the working end is designed and configured such that the tool body assumes a non-circular shape, particularly a shape deviating from a circular shape, when expanding, especially when shifting, and especially when the expansion element is forced inwards, with respect to the central axis. This particularly promotes the previously mentioned advantage that the probability of the reamer becoming stuck, or in particular jammed, in a workpiece to be machined, especially in a bore in the workpiece, is significantly reduced, preferably completely eliminated.

[0065] In one embodiment, the non-circular shape, in particular the shape deviating from the circular shape, results from the fact that the flight circle diameter and the support circle diameter are changed differently during expansion, in particular during displacement, in particular during the insertion of the expansion element.

[0066] According to a further development of the invention, the reamer has at least one expansion reinforcement recess which is arranged in the second tool body sector.

[0067] By means of at least one expansion reinforcement recess, it is advantageously possible to define the expansion characteristic of a reamer during its manufacture – in particular, once during the creation of the at least one expansion reinforcement recess – and thus an enlargement characteristic of the support circle diameter. Specifically, the support circle diameter of a reamer with an expansion reinforcement recess is enlarged more when a predetermined comparative expansion force is applied than the support circle diameter of a reamer without an expansion reinforcement recess when a predetermined comparative expansion force is applied, assuming otherwise identical design.

[0068] In one embodiment, a strain-reinforcing recess of the at least one strain-reinforcing recess is assigned to a support element of the at least two support elements and precedes the respective assigned support element, in particular immediately, in particular directly.

[0069] In one embodiment – ​​where the reamer has exactly two support elements – the reamer has exactly two expansion-reinforcing recesses. In particular, each individual support element is associated with exactly one expansion-reinforcing recess. In particular, the associated expansion-reinforcing recess precedes the respective support element, in particular immediately, in particular directly.

[0070] In one embodiment – ​​where the reamer has exactly three support elements – the reamer has exactly three expansion-reinforcing recesses, which are assigned to the three support elements in pairs. In particular, the assigned expansion-reinforcing recess precedes the respective support element, especially immediately, particularly directly.

[0071] In one embodiment—where the reamer has three expansion-reinforcing recesses—the cutting circle diameter is expanded by up to 0.16% compared to an unexpanded cutting circle diameter, particularly when the expansion element is not inserted into the expansion recess. Specifically, the support circle diameter is expanded by up to 0.09% compared to an unexpanded support circle diameter, particularly when the expansion element is not inserted into the expansion recess. This differential expansion results in a radial second cutting edge projection. Specifically, the radial second cutting edge projection of a reamer with an expansion-reinforcing recess is smaller than the radial first cutting edge projection of an otherwise identical reamer without an expansion-reinforcing recess.In particular, with a reinforcement recess, the support circle diameter expands more when the equivalent expansion force is applied than without a reinforcement recess. Conversely, with a reinforcement recess, the cutting circle diameter expands less when the equivalent expansion force is applied than without a reinforcement recess. This is primarily because, in a reamer without a reinforcement recess, the expansion element can be supported relatively well against the second tool body sector to expand the first tool body sector—and thus the cutting circle diameter. Therefore, the equivalent expansion force acts predominantly to expand the cutting circle diameter. Conversely, in a reamer with a reinforcement recess, the expansion element cannot be supported as effectively against the second tool body sector to expand the first tool body sector—and thus the cutting circle diameter.Consequently, the second tool body sector itself is significantly widened. Thus, the comparative widening force no longer acts predominantly to widen the cutting circle diameter, but also to widen the support circle diameter. The more significantly widened support circle diameter and the less significantly widened cutting circle diameter therefore lead in particular to the reduced radial second cutting edge overhang.

[0072] According to a further development of the invention, the reamer has at least one fluid line outlet, which is assigned to one of the at least two support elements and, particularly in the cutting direction, leads the respective assigned support element, especially directly. This ensures, in particular, that sufficient coolant is present between the support elements and a workpiece to be machined, especially a bore in the workpiece to be machined, so that friction is minimized and the probability of the reamer seizing, especially jamming, is significantly reduced, preferably virtually eliminated.

[0073] In one embodiment – ​​where the reamer has three support elements – the reamer has three fluid line outlets. In particular, the fluid line outlets and the support elements are paired, with each fluid line outlet leading the associated support element, in particular immediately, and especially directly.

[0074] In one embodiment, the reamer has at least one cutting edge fluid outlet assigned to the at least one cutting edge. In particular, each cutting edge of the at least one cutting edge has a separate cutting edge fluid outlet. In particular, the respective cutting edge fluid outlet leads the respective cutting edge, in particular immediately, and in particular directly. In particular, the respective cutting edge fluid outlet opens into the chip space assigned to the respective cutting edge, in particular immediately leading the respective cutting edge.In particular, this ensures that sufficient coolant is present between the cutting edges and a workpiece to be machined, especially a bore in the workpiece to be machined, so that there is as little friction as possible and that the risk of the reamer getting stuck, especially jammed, is significantly reduced, preferably almost non-existent.

[0075] In one embodiment - when the reamer has exactly three cutting edges - the reamer has exactly three cutting edge fluid line outlets that are paired together.

[0076] In one embodiment, the reamer has a fluid line configured to be fluidically connected to a fluid supply line of a machine tool, in particular such that the machine tool can introduce a machining fluid, especially a coolant / lubricant, into the fluid line and thus into the reamer. In particular, the fluid line branches within the reamer and opens into the cutting edge fluid line outlets and the fluid line outlets, so that the machining fluid supplied by the machine tool can exit the reamer through the cutting edge fluid line outlets and the fluid line outlets. In particular, the fluid line is arranged concentrically to the central axis in sections.

[0077] According to a further development of the invention, it is provided that the first tool body sector has a first sector angle ou with respect to the central axis, which is less than 180°.

[0078] In one embodiment, the first sector angle ou is less than 170°, in particular less than 165°, in particular less than 160°, in particular less than 155°, in particular less than 150°, in particular less than 145°. In particular, the first sector angle ou is greater than 100°, in particular greater than 110°, in particular greater than 120°, in particular greater than 130°. In particular, the first sector angle ou is from 145° to 155°.

[0079] Alternatively or additionally, it is provided that the second tool body sector, with respect to the central axis, has a second sector angle 012 that is less than 180°. In one embodiment, the second sector angle 012 is less than 170°, in particular less than 160°, in particular less than 150°, in particular less than 140°, in particular less than 130°, in particular less than 120°, in particular less than 110°. In particular, the second sector angle 012 is greater than 60°, in particular greater than 70°, in particular greater than 80°, in particular greater than 90°, in particular greater than 100°, in particular greater than 110°, in particular greater than 120°. In particular, the second sector angle 012 is from 95° to 105°, or from 105° to 115°, or from 115° to 125°, or from 125° to 135°.

[0080] According to a further development of the invention, it is provided that the at least two support elements are attached to the tool body.

[0081] According to a further development of the invention, it is provided that the working end comprises an alloyed heat-treatable steel or a hot-work steel.

[0082] In one embodiment, the tool body comprises an alloyed heat-treatable steel or a hot-work steel, or is formed from an alloyed heat-treatable steel or a hot-work steel.

[0083] Advantageously, both steels are relatively non-brittle and exhibit sufficient elastic deformability. In particular, the tool body expands elastically when the expansion element is forced in, without entering a plastic deformation range of the selected material, especially steel. Furthermore, when the expansion element is removed, particularly by unscrewing the screw element, the tool body returns to its original shape before the expansion element was forced in.

[0084] The invention will be explained in more detail below with reference to the drawing. The drawing shows:

[0085] Figure 1 shows a schematic representation of an embodiment of a reamer for machining a workpiece in a first view.

[0086] Figure 2 shows a schematic representation of the reamer according to Figure 1 in a second view,

[0087] Figure 3 shows a schematic representation of the reamer according to Figure 1 in a third view, and

[0088] Figure 4 is a schematic representation of the reamer according to Figure 1 in a fourth view. Figure 1 shows a schematic representation of an embodiment of a reamer 1 for machining a workpiece (not shown) in a first - isometric - view.

[0089] The reamer 1 has a tool body 3 with a central axis 5 shown in dashed lines, an imaginary first tool body sector 7.1 of the tool body 3, shown in dashed lines and extending in some areas along a circumferential direction encompassing the central axis 5 and along the central axis 5, an imaginary second tool body sector 7.2, shown in dashed lines and different from the first tool body sector 7.1 and extending in some areas along the circumferential direction and along the central axis 5, and a displacement device 9.

[0090] The tool body 3 further comprises a working end 11 with an end-face expansion recess 13 (see Figure 3). An expansion element 15 is displaceably arranged in the expansion recess 13 along the central axis 5. At least one cutting edge 17 – in this case, three cutting edges 17 – is arranged in the first tool body sector 7.1. The at least one cutting edge 17 is arranged at the working end 11 of the tool body 3. At least two support elements 19 – in this case, three support elements 19 – are arranged in the second tool body sector 7.2. The at least two support elements 19 are spaced apart from each other in the circumferential direction at the working end 11 of the tool body 3. The first tool body sector 7.1 and the second tool body sector 7.2 do not overlap.The displacement device 9 is designed to displace the expansion element 15 along the central axis 5 in order to widen the tool body 3 at the working end 11 in order to change the cutting circle diameter of the at least one cutting edge 17 encompassing the central axis 5. A cutting circle arc segment 21 of the cutting circle having the cutting circle diameter of the at least one cutting edge 17 is shown here in dashed lines.

[0091] The at least one tool body sector 7 extends from the working end 11 along the central axis 5 in the direction of a shank end 23, in particular a clamping end 67, of the reamer 1.

[0092] An extrusion length 25 of a tool body sector 7, selected from the first tool body sector 7.1 and the second tool body sector 7.2, corresponds to an axial extent of an element selected from the at least one cutting edge 17 and the at least two support elements 19. In particular, both tool body sectors 7 have the same extrusion length 25.

[0093] The first tool body sector 7.1 is formed, in particular limited, by an effective end side 27.1 of the at least one cutting edge 17 facing the workpiece and a clamping end side 29.2 of the at least one cutting edge 17 opposite the effective end side 27.1 and facing away from the workpiece.

[0094] The second tool body sector 7.2 is formed, in particular limited, by an effective end side 27.2 of the at least two support elements 19 facing the workpiece and a clamping end side 29.2 of the at least two support elements 19 opposite the effective end side 27.2 and facing away from the workpiece, with respect to the central axis 5.

[0095] The first tool body sector 7.1 and the second tool body sector 7.2 are arranged along the central axis 5 at the same axial height in certain areas.

[0096] The at least one cutting edge 17 has a radial cutting section 31 and, in particular, an axial cutting section 33. The radial cutting section 31 projects, in particular, in a radial direction from the tool body 3, while the axial cutting section 33 projects, in particular, in an axial direction, especially in the direction of the central axis 5, and especially from the end face 35 of the tool body 3 at the working end 11.

[0097] The reamer 1 has at least one fluid line outlet 37.2 - in this case three fluid line outlets 37.2 - which is assigned to a support element 19 of the three support elements 19 and, in particular in a cutting rotation direction 39 (see Figure 2), leads the respective assigned support element 19, in particular immediately, in particular directly.

[0098] The first tool body sector 7.1 has a first sector angle ou with respect to the central axis 5 that is less than 180°. In this case, the first sector angle ou is less than 145°. In particular, the first sector angle ou is greater than 130°.

[0099] Additionally, it is provided that the second tool body sector 7.2, with respect to the central axis 5, has a second sector angle 012 that is less than 180°. In this case, the second sector angle 012 is less than 110°. In particular, the second sector angle 012 is greater than 90°. The tool body 3 in this case is made of an alloy heat-treatable steel or a hot-work steel, or is formed from an alloy heat-treatable steel or a hot-work steel.

[0100] Figure 2 shows the reamer 1 according to Figure 1 in a second view of the end face 35 of the working end 11.

[0101] Identical and functionally equivalent elements are provided with the same reference symbols in all figures, so that reference is made to the preceding description in each case.

[0102] The first tool body sector 7.1 and the second tool body sector 7.2 are arranged offset from each other in the circumferential direction, in particular such that the first tool body sector 7.1 and the second tool body sector 7.2 do not overlap, especially not partially.

[0103] A cutting edge 41 of the cutting edge 17 is arranged in the first tool body sector 7.1. A support element center 43 of the support element 19, particularly with respect to the circumferential direction, is arranged in the second tool body sector 7.2.

[0104] In the present case, the reamer 1 has exactly one and only one first tool body sector 7.1 as the first tool body sector 7.1, and the reamer 1 has exactly one and only one second tool body sector 7.2 as the second tool body sector 7.2.

[0105] All cutting edges 17, in particular their respective cutting edges 41, of the reamer 1 are arranged in the single first tool body sector 7.1. The first tool body sector 7.1 is free of support elements 19, so that no support elements 19 are arranged in the first tool body sector 7.1.

[0106] Furthermore, all support elements 19, in particular their support element center 43, of the reamer 1 are arranged in the single second tool body sector 7.2. The second tool body sector 7.2 is free of cutting edges 17, so that no cutting edges 17 are arranged in the second tool body sector 7.2.

[0107] Advantageously, the reamer 1 has an asymmetrical distribution of the cutting edges 17 and the support elements 19 - with one or more cutting edges 17 in the first tool body sector 7.1 and the support elements 19 in the second tool body sector 7.2 - whereby the advantage is realized that a particularly precise surface can be produced on a workpiece.

[0108] The reamer 1 has three cutting edges 17: a first front cutting edge 17.1 in the cutting direction 39, a second middle cutting edge 17.2 in the cutting direction 39, and a third rear cutting edge 17.3 in the cutting direction 39. In particular, the front cutting edge 17.1 precedes the middle cutting edge 17.2, and in particular, the middle cutting edge 17.2 precedes the rear cutting edge 17.3. In particular, the second tool body sector 7.2 is arranged between the front cutting edge 17.1 and the rear cutting edge 17.3 in the cutting direction 39.

[0109] The reamer 1 has three support elements 19: a front support element 19.1 in the cutting direction 39, a middle support element 19.2 in the cutting direction 39, and a rear support element 19.3 in the cutting direction 39. In particular, the front support element 19.1 precedes the middle support element 19.2, and in particular, the middle support element 19.2 precedes the rear support element 19.3. In particular, the first tool body sector 7.1 is arranged between the front support element 19.1 and the rear support element 19.3 in the cutting direction 39.

[0110] Viewed in the circumferential direction, the middle cutting edge 17.2 of the three cutting edges 17, in particular its cutting edge 41, is arranged diametrically opposite the central axis 5 to the central support element 19.2 of the three support elements 19, in particular to its support element center 43, as viewed in the circumferential direction.

[0111] The expansion recess 13 has a varying wall thickness in the circumferential direction such that the cutting circle diameter and a support circle diameter of the three support elements 19 are changed differently during expansion, in particular during displacement, especially during the insertion of the expansion element 15. In particular, a wall 45, which has the specified wall thickness, is formed by the tool body 3. The cutting circle diameter is increased more than the support circle diameter during expansion, in particular during displacement, especially during insertion of the expansion element 15. The tool body 3 has at least one chip space 47, in particular one chip space 47 for each cutting edge 17, and in particular three chip spaces 47 if there are three cutting edges 17. In particular, each cutting edge 17 is assigned its own chip space 47, with the respective chip space 47 immediately leading the assigned cutting edge 17.

[0112] The chip spaces 47 form the varying wall thickness, in particular because, due to the chip spaces 47, the wall thickness of the tool body 3 in a chip space angle region 49 encompassing the central axis 5, in which a chip space 47 is arranged, is less than the wall thickness in a chip space-free angle region 51, in which no chip space 47 is arranged.

[0113] For clarity, only one of the angle ranges selected from the chip space angle range 49 and the chip space free angle range 51 is provided with a dimension line and a reference symbol, whereby the description also applies to the other angle ranges.

[0114] The working end 11 is designed and configured such that the tool body 3 assumes a non-circular shape, in particular a shape deviating from a circular shape, when expanding, especially when shifting, especially when the expansion element 15 is forced in, with respect to the central axis 5. This is illustrated here by means of a dashed circle 53.

[0115] In an embodiment not shown, the reamer 1 is provided to have at least one expansion reinforcement recess which is arranged in the second tool body sector 7.2.

[0116] The reamer 1 has at least one cutting edge fluid outlet 37.1 – in this case, three cutting edge fluid outlets 37.1 – which is assigned to the at least one cutting edge 17. In particular, each cutting edge 17 of the at least one cutting edge 17 is assigned a separate cutting edge fluid outlet 37.1. In particular, the respective cutting edge fluid outlet 37.1 leads the respective cutting edge 17, in particular immediately, and especially directly. In particular, the respective cutting edge fluid outlet 37.1 opens into the chip space 47 assigned to the respective cutting edge 17, in particular immediately leading the respective cutting edge 17. Figure 3 shows the reamer 1 according to Figure 1, in particular the working end 11, in an enlarged third view, which represents a sectional view along a longitudinal plane having the central axis 5.

[0117] The expansion recess 13 is partially configured as a cylindrical recess 55, in particular as a bore extending along the central axis 5. The expansion recess 13 particularly has a thread 57. Additionally, the expansion recess 13 particularly has a displacement section 59 against which the expansion element 15 rests and along which the expansion element 15 can be displaced. The thread 57 particularly has a diameter that is smaller than the diameter of the displacement section 59. In particular, the expansion recess 13 is configured as a stepped bore. In particular, the expansion recess 13 is conically shaped in sections towards the effective end 11, and in particular has a chamfer 61, which is formed in particular on an edge 63 between an end face 36 of the tool body 3 facing the workpiece and standing transversely on the central axis 5 and a cylindrical surface 65 of the expansion recess 13.

[0118] The expansion element 15 – when arranged as intended in the expansion recess 13 – has a shape rotationally symmetrical about the central axis 5. In particular, the expansion element 15 is frustoconical, specifically such that the expansion element 15 is arranged as intended with a smaller diameter end 67 in the expansion recess 13, in particular so that it is inserted into the expansion recess 13 first. The expansion element 15 further features, in particular, a through opening 69 extending along the central axis 5 with a contact collar 71. In particular, the contact collar 71 has a contact surface 73.1 oriented transversely to the central axis 5.

[0119] The displacement device 9 has a screw element 73. The screw element 73 extends, in particular, through the through-opening 69 of the expansion element 15 and rests with a screw head 75, in particular with a counter-contact surface 73.2 of the screw head 75 oriented transversely to the central axis 5, against the contact collar 71 of the through-opening 69, in particular against the contact surface 73.1 of the contact collar 71. The screw element 73 also engages, in particular, in the thread 57 of the expansion recess 13. In particular, by screwing the screw element 73 into the thread 57, the expansion element 15 is displaced along the central axis 5 and forced into the expansion recess 13. In this process, the tool body 3 is expanded at the working end 11, in particular due to the frustoconical shape of the expansion element 15.

[0120] The screw element 73 further comprises a retaining element 77 which engages the screw element 73 – particularly along the central axis 5 when arranged as intended. In particular, the expansion element 15 is arranged – along the central axis 5 – between the retaining element 77 and the screw head 75, in particular such that the expansion element 15 is displaced, in particular pushed out, of the expansion recess 13, particularly along the central axis 5, when the screw element 73 is unscrewed from the thread 57.

[0121] Figure 4 shows a schematic representation of the reamer 1 according to Figure 1 in a fourth view, which is intended to illustrate an offset of the cutting edges 41.1, 41.2, 41.3 along the central axis 5.

[0122] For this purpose, the working end 11 of the reamer 1 is shown enlarged. For the first cutting edge 17.1, a radial first cut along a first plane 18.1 (at the bottom of the figure) is shown with reference to Figure 2; for the second cutting edge 17.2, a radial second cut along a second plane 18.2 (in the middle of the figure); and for the third cutting edge 17.3, a radial third cut along a third plane 18.3 (at the top of the figure). The tool body 3 and the central axis 5 are also shown in partial detail in each case.

[0123] The first cutting edge 17.1 has a first cutting edge 41.1, which has a first radial cutting section 31.1 that transitions via a first cutting chamfer 20.1 into a first axial cutting section 33.1. The second cutting edge 17.2 has a second cutting edge 41.2, which has a second radial cutting section 31.2 that transitions via a second cutting chamfer 20.2 into a second axial cutting section 33.2. The third cutting edge 17.3 has a third cutting edge 41.3, which has a third radial cutting section.

[0124] 31.3, which has a third cutting edge 20.3 into a third axial cut.

[0125] 33.3 transitions.

[0126] The three axial cutting sections 33.1, 33.2, 33.3 are located along the central axis 5 in the direction of the working end 11 in the same working end-cutting plane 22, which is oriented transversely to the central axis 5. The tool body 3, on the other hand, terminates in a working end-tool body plane 24. The first cutting edge 41.1, in particular the first radial cutting section 31.1, projects along the central axis 5 by a small, initial distance 26.1 from the tool body 3. The first cutting chamfer 20.1 is designed and arranged such that the initial distance 26.1 results. The second cutting edge 41.2, in particular the second radial cutting section 31.2, projects along the central axis 5 by a medium, second distance 26.2 from the tool body 3. The second cutting edge chamfer 20.2 is designed and arranged such that the second distance 26.2 results. The third cutting edge 41.3, in particular the third radial cutting section 31.3, projects along the central axis 5 by a maximum third distance 26.3 from the tool body 3. The third cutting chamfer 20.3 is designed and arranged such that the third distance 26.3 results.

Claims

REQUIREMENTS 1. Reamer (1), comprising: - a tool body (3) having a central axis (5) encompassed by a circumferential direction and an effective end (11) with an end-face expansion recess (13), wherein an expansion element (15) is displaceably arranged in the expansion recess (13) along the central axis (5); - an imaginary first tool body sector (7.1) of the tool body (3) extending in some areas along the circumferential direction and along the central axis (5), in which at least one cutting edge (17) is arranged, which is located at the working end (11) of the tool body (3); - a second tool body sector (7.2) different from the first tool body sector (7.1), which is imagined to extend in some areas along the circumferential direction and along the central axis (5), in which at least two support elements (19) are arranged, which are spaced apart from each other in the circumferential direction at the working end (11) of the tool body (3), wherein - the first tool body sector (7.1) and the second tool body sector (7.2) are non-overlapping, and - a displacement device (9) which is configured to displace the expansion element (15) along the central axis (5) in order to widen the tool body (3) at the working end (11) in order to change a flight circle diameter encompassing the central axis (5) of the at least one cutting edge (17).

2. Reamer (1) according to claim 1, wherein - a cutting edge (17) of which at least one cutting edge (17) and a support element (19) of which at least two support elements (19) are assigned to each other and are arranged opposite each other with respect to the central axis (5).

3. Reamer (1) according to any one of the preceding claims, wherein - the reamer (1) comprising at least one cutting edge (17) or at least two cutting edges (17) which are spaced apart from each other in the circumferential direction.

4. Reamer (1) according to any one of the preceding claims, wherein - a first cutting edge of a first cutting edge (17.1) of the at least one cutting edge (17) and a second cutting edge of a second cutting edge (17.2) of the at least one cutting edge (17) are arranged offset from each other along the central axis (5).

5. Reamer (1) according to any one of the preceding claims, wherein - the reamer (1) having at least one cutting edge (17) having exactly three cutting edges (17) spaced apart from each other in the circumferential direction, wherein - the reamer (1) as having at least two support elements (19) exactly three support elements (19).

6. Reamer (1) according to claim 5, wherein - one cutting edge (17) of the three cutting edges (17) and one support element (19) of the three support elements (19) are assigned to each other and arranged opposite each other with respect to the central axis (5).

7. Reamer (1) according to any one of the preceding claims, wherein - the expansion recess (13) has a varying wall thickness in the circumferential direction such that the flight circle diameter and a support circle diameter of the at least two support elements (19) are changed differently during expansion.

8. Reamer (1) according to any one of the preceding claims, wherein - the working end (11) is designed and arranged in such a way that the tool body (3) assumes a non-circular shape when expanding with respect to the central axis (5).

9. Reamer (1) according to one of the preceding claims, wherein the reamer (1) has at least one expansion reinforcement recess arranged in the second tool body sector (7.2).

10. Reamer (1) according to any one of the preceding claims, wherein - the reamer (1) has at least one fluid line outlet (37.2) which is assigned to a support element (19) of at least two support elements (19) and leads the respective assigned support element (19).

11. Reamer (1) according to any one of the preceding claims, wherein - the first tool body sector (7.1) with respect to the central axis (5) has a first sector angle ou that is less than 180°, and / or - the second tool body sector (7.2) with respect to the central axis (5) has a second sector angle 012 which is less than 180°.

12. Reamer (1) according to any one of the preceding claims, wherein - which at least two support elements (19) are attached to the tool body (3).

13. Reamer (1) according to any one of the preceding claims, wherein - the working end (11) is made of an alloyed heat-treatable steel or a hot-work steel.

14. Reamer (1) according to any one of the preceding claims, wherein - the reamer (1) has exactly one first tool body sector (7.1) and / or exactly one second tool body sector (7.2) as the first tool body sector (7.2).

15. Reamer (1) according to one of the preceding claims, wherein the first tool body sector (7.1) is free of support elements (19) of the reamer (1), and / or wherein the second tool body sector (7.2) is free of cutting edges (17) of the reamer (1).

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