Machining tool

Abstract

Machining tool with which machining can be carried out on a workpiece surface (25) or in a workpiece bore when the tool is rotated about a tool axis (W), wherein the machining tool has at least one compliant damping element (9), and wherein during machining the machining tool is in contact with the workpiece surface (25) or the workpiece bore via its damping element (9), whereby tool and workpiece vibrations can be reduced, characterized in that the tool has a coolant channel (27) with at least one channel outlet (29) in the area of ​​the contact point of the damping element (9) with the workpiece surface (25).

Description

[0001] The invention relates to a machining tool according to the preamble of claim 1.

[0002] For example, such a machining tool could be a milling tool for plunge milling or face milling. In this case, the tool can have end cutting edges. During the milling process, the milling tool rotates around a tool axis perpendicular to the workpiece surface and moves along the workpiece surface with a feed motion transverse to the tool axis.

[0003] During the milling process, the cutting edges of the milling tool are subjected to a cutting force. This force attempts to displace the tool translationally, resulting in tool flexion. The tool bends until it builds up sufficient preload, causing it to briefly return to its original state. This process repeats very rapidly during milling, which can lead to tool vibrations and impair the surface quality of the workpiece.

[0004] From EP 2 399 698 B1, a tool holder equipped with a damping element is known. From EP 1 339 517 B1, a tool for machining metals with a vibration damping element is known. From EP 1 292 417 B1, a drill with a vibration damper is known. DD 1 07 401 A1 discloses a milling tool, such as a face milling head, corner milling head, end mill, or face mill for high material removal rates. From DE 24 16 157 A1, a drilling tool is known. US 2010 / 0 172 708 A1 discloses a solution for reducing workpiece vibrations. From DD 2 05 635 A1, a drilling tool for reaming is known. GB 2 574 437 A discloses a cutting tool.

[0005] The object of the invention is to provide a machining tool in which tool vibration during machining can be avoided in a structurally simple manner.

[0006] The problem is solved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0007] The invention generally relates to a machining tool with which machining can be performed on a workpiece surface or in a workpiece bore during tool rotation about a tool axis. According to claim 1, the machining tool has at least one compliant damping element. During machining, the machining tool is in contact, in particular pressure contact, with the workpiece surface or the workpiece bore via its damping element, thereby reducing tool and workpiece vibrations.

[0008] The core of the invention lies in the fact that, to prevent / dampe vibrations, the workpiece is pre-tensioned by means of a damping element attached to the machining tool, thus preventing it from vibrating. For example, the machining tool can be used in plunge milling. In this case, the machining tool makes initial contact with the workpiece via the damping element. The contact force exerted by the damping element increases with the tool feed rate.

[0009] Alternatively, the machining tool can be used when milling the workpiece from one side (in one plane). In this case, the initial contact of the milling tool with the workpiece occurs via the cutting edges. As the tool continues to plunge into the workpiece material, the damping element collides with the workpiece. The resulting pressure force prevents the workpiece or the tool from vibrating.

[0010] In one technical implementation, the damping element, when not in use, can protrude beyond at least one cutting edge or tool tip. During machining, the damping element can be moved into a working position in which, by utilizing the protrusion and preferably by building up a restoring force, it is adjusted to the level of the cutting edge to ensure chip engagement between the cutting edge and the workpiece surface.

[0011] Preferably, the damping element can be mounted in the machining tool with adjustable stroke. In the non-use position, the damping element can be supported against a pre-stroke stop of the tool by means of a damping mass. Furthermore, in the use position, particularly when the restoring force builds up, the damping element can be retracted from the pre-stroke stop. When a force is applied during machining, energy is absorbed, causing the damping mass to deform and thereby at least partially dissipate the applied forces.

[0012] In a preferred embodiment, the damping element can be brought into contact, particularly pressure contact, with the workpiece surface or the workpiece bore during machining in the axial and / or radial direction. In this case, the damping element can be adjusted by stroke in the axial and / or radial direction between the operating position and the non-operating position.

[0013] In one specific embodiment, the cutting edge of the tool can be a face cutting edge, which is arranged together with the damping element at a tool tip of the machining tool.

[0014] To achieve the lifting motion, the damping element between the forward stroke stop and a return stroke stop can be adjusted. The axial or radial distance between the forward stroke stop and the return stroke stop defines a maximum stroke length.

[0015] In a technical implementation, the damping element, the forward stroke stop, the return stroke stop, and / or the damping mass can be part of a stroke adjustment unit. This unit can be arranged in a, in particular, hollow cylindrical mounting profile of the machining tool. The hollow cylindrical mounting profile can be open at the end face of the tool tip.

[0016] Preferably, the forward stroke stop can be implemented as a stop sleeve through which the damping element is guided in a stroke-adjustable manner. The return stroke stop can be spaced axially from the forward stroke stop, forming an axial gap. Furthermore, the damping element can have a larger-diameter annular collar that interacts with both the forward stroke stop and the return stroke stop. The larger-diameter annular collar can overlap an end face of the stop sleeve and be guided in a stroke-adjustable manner between the end face of the stop sleeve and the return stroke stop.

[0017] The damping mass can, for example, be an elastomer body and / or be supported between the return stroke stop and the damping element, in particular the larger diameter ring collar of the damping element.

[0018] With regard to functional expansion, it is preferred if the forward stroke stop and / or the return stroke stop are height-adjustable, for example, along the tool axis. In this case, the forward stroke stop and / or the return stroke stop can be positioned, thereby allowing the position of the working position and / or the non-working position to be varied in the axial direction.

[0019] In one embodiment, the damping element can be a sleeve-shaped hollow profile section that is guided coaxially along the tool axis with adjustable stroke. Alternatively or additionally, the damping element can have an element head that can be brought into contact with the workpiece surface during machining.

[0020] It is preferred that the machining tool be provided with a coolant supply to cool or lubricate the contact point between the damping element and the workpiece. Preferably, the coolant supply can have a coolant channel within the tool. According to the invention, the coolant channel has at least one outlet in the area of ​​the contact point between the damping element and the workpiece surface. It is preferred that the hollow profile of the damping element is part of the coolant channel. In this case, at least one outlet can be formed in the element head of the damping element.

[0021] In a first embodiment, the head of the damping element can be spherical with its apex lying on the tool axis. During machining, the head of the damping element is in point contact with the workpiece surface at its apex.

[0022] Alternatively, the damping element can be ring-shaped, resulting in a ring-shaped pressure system during machining.

[0023] Exemplary embodiments of the invention are described below with reference to the accompanying figures.

[0024] They show: Fig. 1 and Fig. Two different views of a milling tool, Fig. Figures 3 to 9 each show different views of further exemplary embodiments.

[0025] In the Fig. Figure 1 shows a partial perspective view of a milling tool in the region of its tool tip 1. The milling tool has a cylindrical body which has a clamping shank (not shown) on the side facing away from the tool tip 1. A total of three circumferentially distributed end cutting edges 3, 5, 7 are arranged at the tool tip 1 of the milling tool.

[0026] The damping element 9 is located between a forward stroke stop 11 and a return stroke stop 13 by a maximum stroke distance h ( Fig. 2) Height adjustable. In the Fig. 2 The forward stroke stop 11 is implemented as a stop sleeve within which the damping element 9 is guided. The stop sleeve 11 is screwed into a hollow cylindrical receptacle 10 of the milling tool, which is open at the end face at the tool tip 1. The return stroke stop 13 is spaced from a stop sleeve end face 15 by an axial distance a, forming an axial gap 14. The damping element 9 is implemented as a sleeve-shaped hollow profile part that is coaxially adjustable along the tool axis W. The damping element 9 has, on the one hand, a large-diameter ring collar 17 that overlaps the stop sleeve end face 15 and is adjustable between the stop sleeve end face 15 and the return stroke stop 13. In addition, according to the Fig. 2 the damping mass 19 is designed as an elastomer body which is supported between the return stroke stop 13 and the large diameter ring collar 17 of the damping element 9.

[0027] In the Fig. 2 is both the stop sleeve 11 and the return stroke stop 13 in threaded engagement 21 with the hollow cylindrical tool holder 10. In this way, the axial position of the stop sleeve 11 and / or the return stroke stop 13 can be adjusted.

[0028] In the Fig. Figure 2 shows the damping element 9 in a non-use position N. In the non-use position N, an element head 23 of the damping element projects beyond the end faces 3, 5, 7 with a projection Δx.

[0029] In the Fig. Figure 3 shows the milling tool during machining of a workpiece surface 25. In this case, the damping element 9 is in a service position G in which the damping element 9 is adjusted up to the level of the tool cutting edges 3, 5, 7 by using up the overhang Δx and building up a restoring force in order to ensure chip engagement of the tool cutting edges 3, 5, 7 with the workpiece surface 25.

[0030] In the, in the Fig. In the operating position G shown in Figure 3, the damping element 9 with its element head 23 is in pressure with the workpiece surface 25, thereby reducing tool and workpiece vibrations.

[0031] To prevent damage to the workpiece surface 25 at the contact point between the element head 23 of the damping element 9 and the workpiece surface 25, the milling tool is provided with a coolant supply via a coolant channel 27. This channel extends coaxially to the tool axis W within the milling tool. The coolant channel 27 also incorporates the inner hollow profile of the damping element 9, through which the coolant is guided directly to the element head 23 and from there to the contact point via channel outlets 29.

[0032] The stroke h of the damping element provided by the stroke adjustment unit must be larger than the overhang Δx of the damping element 9 present in the non-use position N.

[0033] In the Fig. 4 is in a view according to the Fig. Figure 2 shows a further embodiment variant. Its structure and function are identical to those in the previous embodiment. In contrast to the Fig. 1 or Fig. 2 is in the Fig. 4 The element head 23 is not flat, but rather spherically bulged, with an apex S lying on the tool axis W. The channel outlet 29 is located directly at the apex S. In this way, compared to the previous embodiment, a substantially point-like pressure system is created between the damping element 9 and the workpiece surface 25.

[0034] In the Fig. Figure 5 shows a further embodiment in which the milling tool does not have end cutting edges 3, 5, 7, but rather side cutting edges 31, 33 spaced axially from the tool tip 1. With the in the Fig. Using the milling tool indicated in section 5, a workpiece side 35 is milled, which is aligned parallel to the tool axis W. At the start of the machining process, initial tool contact with the workpiece surface 25 occurs via the lateral tool cutting edges 31, 33 during a feed movement. As the tool continues to plunge into the workpiece material, pressure contact between the damping element 9 and the workpiece surface 25 occurs only after a time delay.

[0035] In the Fig. Figure 6 indicates another machining tool. In contrast to the previous embodiments, in the Fig. 6 the damping element 9 is ring-shaped. In this case, a ring-shaped pressure system results during machining, with the cutting edges 37 forming radially outside the ring-shaped damping element 9. In the Fig. 6 The channel outlets 29 of the coolant channel 27 are positioned directly in the annular damping element 9. In the Fig. In contrast, the channel outlets 29 are positioned both in the annular damping element 9 and radially within the annular damping element 9. Unlike in the Fig. 8 the damping element 9 is free of channel outlets 29, while only radially within the annular damping element 9 is a channel outlet 29 of the coolant channel 27 positioned.

[0036] In the Fig. Figure 9 shows a further embodiment in which the damping element 9 is not only flexibly mounted in the axial direction, but also flexibly mounted in the radial direction. In this way, the milling tool can also be supported laterally against the workpiece during machining. REFERENCE MARK: 1 tool tip 3, 5, 7 cutting edges 9 damping element 10 Recording profile 11 Stop sleeve 13 Return stroke stop 15 Stop sleeve end face 17 ring bundles with a larger diameter 19 Damping mass 21 Thread engagement 23 Element head 25 workpiece surface 27 Coolant channel 29 Canal outlet 31, 33 Tool cutting edges 35 workpiece side 37 Tool cutting edge a axial distance h Hubweg Δx overhang G Operating position N Non-use position S vertex

Claims

[1] Machining tool with which, during tool rotation about a tool axis (W), machining can be carried out on a workpiece surface (25) or in a workpiece bore, wherein the machining tool has at least one flexible damping element (9), and wherein during machining, the machining tool is in contact with the workpiece surface (25) or the workpiece bore via its damping element (9), whereby tool and workpiece vibrations can be reduced, characterized by that the tool has a coolant channel (27) with at least one channel outlet (29) in the region of the contact point of the damping element (9) with the workpiece surface (25). [2] Machining tool according to claim 1, characterized byin that the damping element (9) projects beyond at least one tool cutting edge (3, 5, 7) or a tool tip (1) in a non-use position (N) with a projection (Δx) in the axial direction and / or in the radial direction, and in that the damping element (9) is adjusted in a use position (G) during chip machining, specifically by utilizing the axial and / or radial projection (Δx) and by building up a restoring force, and / or in that in the use position (G) the damping element (9) is adjusted to the level of the tool cutting edge (3, 5, 7) in order to ensure chip engagement of the tool cutting edge (3, 5, 7) with the workpiece surface (25) or the workpiece bore. [3] Machining tool according to claim 1 or 2, characterized bythat the damping element (9) is mounted in the machining tool so that its stroke can be adjusted, and that the damping element (9) presses against a pre-stroke stop (11) of the tool in the non-use position (N) by means of a damping mass (19), and that the damping mass (19) dissipates the energy introduced during machining by deformation, and / or that in the use position (G) the damping element (9) is set back from the pre-stroke stop (11) by a stroke distance (h), and / or that during machining the damping element (9) can be brought into contact, namely pressure contact, with the workpiece surface (25) or with the workpiece bore in the axial direction and / or in the radial direction, and / or that the damping element (9) is stroke-adjustable in the axial direction and / or in the radial direction. [4] Machining tool according to one of the preceding claims, characterized bythat the tool cutting edge (3, 5, 7) is a front cutting edge, and that both the damping element (9) and the front cutting edge (3, 5, 7) are arranged on a tool tip (1) of the machining tool, and / or that the damping element (9), the forward stroke stop (11), a return stroke stop (13) and / or the damper mass (19) are components of a stroke adjustment unit which can be used in a hollow cylindrical receiving profile (10) of the machining tool which is open at the end face of the tool tip (1). [5] Machining tool according to one of claims 3 or 4, characterized bythat the forward stroke stop (11) is implemented as a stop sleeve through which the damping element (9) is guided in a stroke-adjustable manner, and / or that the return stroke stop (13) is spaced apart from the forward stroke stop (11) by an axial distance (a) to form an axial gap (14), and that the damping element (9) has a large-diameter annular collar (17) which engages over an end face (15) of the stop sleeve (11) and is adjustable by a stroke distance (h) between the stop sleeve end face (15) and the return stroke stop (13), and / or that the damper mass (19) can be supported between the return stroke stop (13) and the damping element (9), and / or that the forward stroke stop (11) and / or the return stroke stop (13) are height-adjustable, specifically in the axial direction and / or in the radial direction, namely to adjust the use position (G) and / or the non-use position (N). [6] Machining tool according to one of the preceding claims, characterized bythat the damping element (9) is a sleeve-shaped hollow profile part which is adjustable at least along the tool axis (W), and / or that the damping element (9) has an element head (23) which can be brought into contact with the workpiece surface (25) or the workpiece bore, and / or that the hollow profile of the damping element (9) is a component of the coolant channel (27), and / or that at least one channel outlet (29) is formed in the region of the element head (23) of the damping element (9). [7] Machining tool according to one of the preceding claims, characterized by that the element head (23) of the damping element (9) is dome-shaped with a vertex (S) lying on the tool axis (W), by means of which a point-like contact with the workpiece surface (25) or the workpiece bore can be produced. [8] Machining tool according to one of the preceding claims, characterized bythat the damping element (9) is annular, so that an annular contact is produced during machining, and that the tool cutting edge (37) is arranged radially outside the annular damping element (9), and / or that the at least one channel outlet (29) of the coolant channel (27) is positioned in the annular damping element (9) and / or radially inside the annular damping element (9). [9] Machining tool according to one of the preceding claims, characterized by that the machining tool is a milling tool for plunge milling, in which a first tool contact with the workpiece surface (25) or the workpiece bore takes place via the damping element (9) in a feed movement, and that the pressing force building up in the damping element (9) increases with progressive tool feed. [10] Machining tool according to one of claims 1 to 8, characterized bythat the tool is a milling tool by means of which a milling of a workpiece side (35) is carried out which is aligned parallel to the tool axis (W), and that in a feed movement a first tool contact with the workpiece surface (25) or the workpiece bore takes place via the tool cutting edge (35), wherein upon further tool immersion into the workpiece material the damping element (9) comes into contact with the workpiece surface (25) or the workpiece bore.

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