Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23F—MAKING GEARS OR TOOTHED RACKS
  • B23F5/00—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made
  • B23F5/12—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made by planing or slotting
  • B23F5/16—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made by planing or slotting the tool having a shape similar to that of a spur wheel or part thereof
  • B23F5/163—Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made by planing or slotting the tool having a shape similar to that of a spur wheel or part thereof the tool and workpiece being in crossed axis arrangement, e.g. skiving, i.e. "Waelzschaelen"
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B5/00—Turning-machines or devices specially adapted for particular work; Accessories specially adapted therefor
  • B23B5/36—Turning-machines or devices specially adapted for particular work; Accessories specially adapted therefor for turning specially-shaped surfaces by making use of relative movement of the tool and work produced by geometrical mechanisms, i.e. forming-lathes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
  • B23G9/00—Working screws, bolt heads, or nuts in conjunction with thread cutting, e.g. slotting screw heads or shanks, removing burrs from screw heads or shanks; Finishing, e.g. polishing, any screw-thread
  • B23G9/001—Working screws
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q27/00—Geometrical mechanisms for the production of work of particular shapes, not fully provided for in another subclass
  • B23Q27/006—Geometrical mechanisms for the production of work of particular shapes, not fully provided for in another subclass by rolling without slippage two bodies of particular shape relative to each other
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2265/00—Details of general geometric configurations
  • B23B2265/32—Polygonal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2265/00—Details of general geometric configurations
  • B23B2265/32—Polygonal
  • B23B2265/326—Hexagonal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23F—MAKING GEARS OR TOOTHED RACKS
  • B23F21/00—Tools specially adapted for use in machines for manufacturing gear teeth
  • B23F21/04—Planing or slotting tools

Definitions

• the present invention relates to a tool and a method for machining a workpiece.
• the tool according to the invention and the method according to the invention are particularly suitable for producing an outer contour on a workpiece which essentially corresponds to a regular convex polygon in the cross-sectional profile of the workpiece.
• a regular convex polygon is understood to be a polygon whose edges touch or intersect only in the corner points, in which all interior angles are less than 180 ° and which is both equilateral and equiangular. Examples of such regular convex polygons are equilateral triangles, squares, equilateral pentagons, equilateral hexagons, etc.
• a typical application of such a cross-sectional profile is the production of a hexagon on a workpiece.
• the workpiece can be a screw or a bolt with a hexagon.
• the workpiece otherwise has a round cross-section and only has flat surfaces on the circumference of the otherwise round or cylindrical workpiece in the area in which the hexagon or polygon is arranged.
• the polygon hitting enables the production of flat surfaces on an otherwise round outer surface of the workpiece.
• This machining process typically takes place on a lathe, with not only the workpiece but also the tool being driven.
• the workpiece in the main spindle and the rotating impact tool in the turret of the machine run in a synchronous transmission ratio to each other.
• the number of surfaces generated on the workpiece depends on this transmission ratio of workpiece to tool and the number the cutting edge on the tool.
• the case which is practically significant in the prior art, provides, for example, that the tool rotates at twice the speed compared to the workpiece, the number of cutting edges multiplied by a factor of 2 resulting in the number of polygonal flat surfaces generated.
• a hexagonal profile can be produced by means of polygonal hammering with a tool that has three cutting blades regularly distributed over the circumference.
• this object is achieved by a skiving tool, with a shank that extends along a longitudinal axis of the tool, and a cutting head which is arranged at a front end of the shank, the cutting head having a plurality of circumferentially angeord designated teeth, each of the teeth viewed in a cross-section orthogonal to the longitudinal axis has a convex rounded contour, the contour at a first end either directly or via an interposed first concave transition into the convex rounded contour of a first adjacent tooth the plurality of teeth merges and at a second end opposite the first end either directly or via a second concave transitional contour arranged between them merges into the convex rounded contour of a second adjacent tooth of the plurality of teeth, and one in the cross section as a distance between d
• the width of each tooth of the plurality of teeth measured at the first end and the second end is greater than a height of the respective tooth measured in the cross section orthogonal to the width
• the object is achieved by a method for machining a workpiece, which has the following steps:
• an outer contour on the workpiece with the help of the skiving tool during skiving, the outer contour to be produced in the cross-sectional profile of the workpiece essentially corresponding to a regular convex polygon, and with skiving, the skiving tool and the workpiece rotating with opposite directions of rotation, an axis of rotation of the skiving tool is aligned at a defined cross-axis angle with respect to an axis of rotation of the workpiece and the skiving tool and / or the workpiece are simultaneously moved in a translatory manner to generate a feed movement.
• the skiving tool used in the method according to the invention is preferably the skiving tool according to the invention.
• the present invention is thus a completely new way. Instead of the previously known manufacturing processes such as milling and polygon hitting, a skiving process using a corresponding skiving tool is used to produce the polygonal profile. Skiving has been known per se for a long time. However, the idea of using power skiving to produce a polygonal profile is completely new.
• Power skiving is typically used for the production of gears, be it
• Skiving is typically used in the manufacture of gears as an alternative to hobbing or gear shaping. Compared to hobbing and gear shaping, it enables a significant reduction in machining times. In addition, a very high processing quality can be achieved. Power skiving therefore enables a very productive and at the same time high-precision manufacture of gears.
• the workpiece and the tool are driven with a coordinated (synchronized) speed ratio.
• the workpiece and tool are operated in opposite directions or in opposite directions. opposite direction of rotation driven.
• the workpiece and tool are driven in the same direction of rotation.
• the tool is employed obliquely, at a predetermined angle, which is usually referred to as the cross-axis angle, relative to the workpiece.
• the axis cross angle denotes the angle between the axis of rotation of the power skiving tool and the axis of rotation of the workpiece to be machined.
• the tool and / or the workpiece is also moved in a translatory manner.
• the resulting relative movement between the roller skiving tool and the workpiece is therefore a type of screwing movement that has a rotational component (rotary component) and a thrust component (translational component).
• the workpiece is machined with the teeth arranged on the circumference of the cutting head of the peeling tool.
• the crossed axis arrangement creates a relative speed between tool and workpiece. This relative movement is used as a cutting movement and has its main cutting direction along the tooth gap of the workpiece. It is therefore said that the chip is "peeled off” during machining.
• the size of the cutting speed depends on the size of the axis intersection angle of the feed movement and on the speed of the machining spindles.
• the power skiving tool according to the invention is equipped with convex rounded teeth that are significantly flatter or less curved.
• the individual teeth are preferably continuously curved.
• the teeth have no kinks or corners when viewed in cross-section orthogonal to the longitudinal axis of the tool. In the cross section, each tooth therefore has a continuously and steadily running tangent slope.
• a "convexly rounded" contour is understood to mean any type of outwardly curved contour that is rounded, that is to say without clear corners and edges.
• this contour is not necessarily adapted to a circular shape or exactly circular, but can also be elliptical or oval or have some other rounded free shape.
• a convexly rounded free form is actually used as the contour in said cross section orthogonal to the longitudinal axis.
• a concave transition contour can be provided or a direct transition between the individual teeth can be implemented. If a concave transition structure is provided between the individual teeth, this is preferably designed to be small compared to the teeth. The smaller this transition structure, the easier it is to create the corners of the polygonal profile on the workpiece.
• the concave transition structure can also be quite angular and, unlike the convexly rounded contour of the teeth, does not have to be rounded.
• an essential feature of the power skiving tool according to the invention lies in the type of configuration of the individual teeth, which, viewed in the cross-section orthogonally to the longitudinal axis, are preferably significantly wider than they are high.
• the width b is measured as the distance between the first end and the second end of each tooth.
• the height h is measured as a height of the respective tooth measured orthogonally to the width and centrally between the first end and the second end in the same cross section.
• the height h is preferably the distance from a point on the contour of the tooth, which is equidistant from the first and the second end, to a connecting line between the first and the second end.
• the length of the last-mentioned connecting line corresponds to the width of the tooth.
• the corner machining of the polygonal profiles is essentially carried out through the transitions between the individual teeth.
• the power skiving tool is preferably rotated at a first speed and the workpiece at a second Speed rotates, the second speed being an integral multiple of the first speed.
• the workpiece is therefore typically rotated faster than the tool.
• this per se as well as the other parameters of the skiving process correspond to the conventional skiving process, which is used for the production of gears.
• the width of each tooth of the plurality of teeth is more than twice as large as the height of the respective tooth. Particularly before given to the width of each tooth is more than three times as large as the height of the respective tooth.
• the teeth are thus extremely flat compared to the teeth of a classic power skiving tool. This is particularly advantageous in order to ensure that the planarity of the flat surfaces to be produced on a polygonal profile is as precise as possible. According to the invention it can even be provided that the ratio of width to height of each tooth is even greater than 5: 1, 6: 1 or 7: 1.
• Another feature of the described flat or slightly curved configuration of the individual teeth can be that a first tangent applied in the cross section to the first end of the convex rounded contour of each tooth in the cross section orthogonal to the longitudinal axis of the tool the second end of the convexly rounded contour intersects the second tangent at an angle a, where 60 ° ⁇ a ⁇ 140 ° applies. Preferably even 80 ° ⁇ a ⁇ 130 ° applies.
• teeth of conventional skiving tools typically have two opposite side flanks, which are aligned almost parallel or even exactly parallel to one another at the transition between the individual teeth, so that the tangents described in this case either have no intersection point or below would enclose a much smaller angle.
• the first and the second concave transition structure that is, the transition structure between the individual teeth of the Skiving tool, viewed in the cross section orthogonal to the longitudinal axis, a radius.
• This radius designed as a transition contour, also cuts with the machining, as already mentioned, and thus machines the workpiece.
• each tooth of the plurality of teeth has an identical shape to the other teeth of the plurality of teeth.
• the power skiving tool cuts that is on the entire circumference during the skiving processing, each tooth being rolled over one of the flat surfaces during the production of a polygonal profile in order to machine them.
• each of the plurality of teeth on a front end of the cutting head facing away from the shank has a planar rake face which is inclined at an angle other than 90 ° with respect to the longitudinal axis.
• the rake faces are thus typically arranged on an upper side of the teeth; they form the front end of the cutting head, which faces away from the shank of the power skiving tool.
• the rake faces are typically designed as planar surfaces.
• the rake faces are preferably inclined, that is to say not arranged perpendicular to the longitudinal axis.
• the rake faces of all teeth can be arranged in a common conical surface which is rotationally symmetrical to the longitudinal axis.
• a transition surface is arranged between the clamping surfaces of two adjacent teeth, which is also arranged at the front end of the cutting head and directly adjoins the chip surfaces of the two adjacent teeth.
• the individual rake faces of the teeth are then in different planes. Individual step-like steps are then created between the individual teeth on the face or between the rake faces. The latter comes about in particular because the rake faces of the teeth are typically produced with a grinding wheel.
• the inventive According to the power skiving tool can, as already mentioned, however, also be designed in such a way that all rake faces are arranged in a common conical surface.
• the power skiving tool has a total of twenty-four teeth. Due to this relatively high number of teeth, the production of polygonal profiles is significantly faster than using classic milling and even faster than using polygon turning.
• the teeth each have a circumferentially arranged flank which is aligned obliquely to the longitudinal axis.
• the flanks of the teeth therefore preferably run non-parallel to the longitudinal axis.
• the cutting head can be releasably attached to the shaft.
• the entire cutting head can be exchanged when worn and replaced with a new one.
• Various interfaces come into consideration as the interface between the cutting head and the shaft.
• the interface preferably has a screw connection.
• the cutting head or at least the teeth arranged on it are preferably made of hard metal, whereas the shaft of the power skiving tool according to the invention is typically made of steel. Depending on the size of the skiving tool, however, the entire tool can also be made of hard metal. It is also possible to equip the cutting head of the power skiving tool with individual indexable inserts that form the teeth. Furthermore, hard metal cutting edges, which form the teeth, can be soldered onto the replaceable head.
• FIG. 1 is a perspective view of an embodiment of the skiving tool according to the invention.
• FIG. 2 shows a side view of the power skiving tool shown in FIG. 1;
• FIG. 3 shows a detailed view from FIG. 2;
• Fig. 4 is a plan view from below of the tool skiving tool shown in Figures 1 and 2;
• FIG. 5 shows a detail from FIG. 4
• FIG. 6 shows the detail shown in FIG. 5 in a sectional view orthogonal to the longitudinal axis of the power skiving tool
• FIG. 7 shows a perspective view of the cutting head of the power skiving tool shown in FIG. 1;
• FIG. 8 shows a detail from FIG. 7;
• FIG. 9 shows a perspective view of the power skiving tool shown in FIG. 1 together with a workpiece to be machined
• FIG. 10a-d shows several views to illustrate a skiving machining of a workpiece with the aid of the skiving tool according to the invention.
• 1 shows a perspective view of an exemplary embodiment of the power skiving tool according to the invention.
• the power skiving tool is identified therein in its entirety with the reference number 10.
• the power skiving tool 10 has a shank 12 which extends along a longitudinal axis 14.
• the shaft 12 is cylindrical. In principle, however, this can also have a different shape, that is, for example, be designed in the shape of a cuboid.
• the power skiving tool 10 has a cutting head 16 which is arranged on a front end of the shaft.
• a multiplicity of teeth 18, which are distributed over the circumference of the cutting head 16, are arranged on the cutting head 12.
• the teeth 18 have a convexly rounded contour. More precisely, the teeth 18 have this convex rounded contour in a cross section orthogonal to the longitudinal axis 14, as is shown in FIG. 6.
• the teeth 18 of the power skiving tool 10 according to the invention are neither angular nor tapering to a point. They are designed much more rounded, which means that they have no corners or sharp edges. Another feature of the skiving tool 10 according to the invention can be seen in the fact that the teeth 18 are significantly flatter or less strongly curved than is the case with conventional skiving tools that are used to produce gears.
• the teeth 18 have a rake face 20 on an end of the teeth 18 facing away from the shaft 12.
• the rake faces 20 of all teeth 18 in the power skiving tool 10 according to the exemplary embodiment shown here lie in a common plane.
• This plane is a conical plane which runs all around at a constant angle relative to the longitudinal axis 14.
• the rake face Chen 20 of the individual teeth are arranged in different planes, then between the rake faces 20 of two adjacent teeth 18 a kind of stair step is created.
• the power skiving tool 10 has a total of twenty-four such teeth 18. These twenty-four teeth 18 are evenly distributed over the circumference of the cutting head 16 and protrude in a star shape from its circumference. As can be seen from the figures, however, the teeth 18 do not project exactly in the radial direction (orthogonal to the longitudinal axis 14) from the circumference of the cutting head 16.
• each of the teeth 18 has a flank 22 which represents the radially outermost part of each tooth 18 and thus also the radially outermost part of the cutting head 16.
• These flanks 22 are skewed with respect to the longitudinal axis 14, which can be seen in particular from FIG. 3.
• FIG. 5 and 6 illustrate the slight curvature and flat configuration of the teeth 18, which is characteristic of the power skiving tool 10 according to the invention.
• FIG. 6 shows a detail of the cutting head 16 in a cross section which is oriented orthogonally to the longitudinal axis 14.
• the teeth 18, according to the exemplary embodiment shown here merge directly into one another.
• each tooth 18 in the cross section shown in FIG. 6 merges directly into the convex rounded contour of an adjacent tooth 18 'at its first end 24 and directly into the convex rounded contour at its second end 26 opposite the first end 24 Contour of its second adjacent tooth 18 "passes.
• concave transition contours can also be provided between the individual teeth 18, but compared to the convexly rounded contours that form the teeth 18 in the cross section shown comparatively are small. Radii, for example, come into consideration as concave transition contours between the individual teeth 18.
• a width b of each tooth 18 measured as the distance between the first end 24 and the second end 26 in the cross section shown in FIG is significantly greater than a height h of the respective tooth 18 measured in the cross section orthogonal to the width b and centrally between the first end 24 and the second end 26.
• a width b of each tooth 18 measured as the distance between the first end 24 and the second end 26 in the cross section shown in FIG is significantly greater than a height h of the respective tooth 18 measured in the cross section orthogonal to the width b and centrally between the first end 24 and the second end 26.
• the length of the connecting line 30 corresponds to the width b of the tooth 18.
• the point 28 is a point at the zenith of the tooth, which is the same distance from the first end 24 and the second end 26.
• a first tangent 32 applied in the cross section shown in FIG. 6 to the first end 24 of the convex rounded contour of the tooth 18 and a second tangent 34 applied in the cross section to the second end 26 of the convex rounded contour of the tooth 18 intersect at an angle ⁇ , which is preferably in the range of 60 ° ⁇ a ⁇ 140 °.
• the angle a is an interior angle measured at the intersection of the two tangents 32, 34 within the imaginary triangle, the triangles of which are the intersection 36 of the two tangents 32, 34, the first end 24 and the second end are 26.
• the individual teeth 18 preferably all have an identical shape, which corresponds to the shape mentioned above.
• the teeth 18 are preferably made of hard metal, while the shaft 12 is preferably made of steel.
• the power skiving tool 10 according to the invention is particularly suitable for producing an outer contour which essentially corresponds to a regular convex polygon in the cross-sectional profile of the workpiece.
• the term "essentially”, which is assigned to the term “regular convex polygon”, is intended to clarify at this point that the contour to be produced on the workpiece in the overall view is a regular polygonal cross-sectional profile, which at the microscopic level or already In the detailed view, however, it does not necessarily correspond exactly to a regular polygon due to manufacturing inaccuracies. For example, individual roundings can occur in the corners of the polygonal profile.
• FIG. 9 illustrates quite generally the type of interaction of the skiving tool 10 with a workpiece 38.
• both the skiving tool 10 and the workpiece 38 are rotated.
• the power skiving tool 10 and the workpiece 38 are rotated with mutually opposite or opposite directions of rotation.
• the workpiece 38 is rotated clockwise and the skiving tool 10 is rotated counterclockwise.
• the power skiving tool 10 is rotated about its longitudinal axis 14.
• the longitudinal axis of the workpiece 38 serves as the axis of rotation 40 of the workpiece 38.
• the two axes of rotation 14, 40 are not parallel, but transverse to one another at a so-called cross-axis angle.
• This oblique arrangement of the axes of rotation 14, 40 to one another is characteristic of power skiving.
• the crossed axis arrangement creates a relative speed between the power skiving tool 10 and workpiece 38.
• FIGS. 10a-10d which serves to illustrate the power skiving process.
• tool 10 and / or workpiece 38 is also moved in a translatory manner. In this manner and way, a kind of screwing movement is created through which the chip lifted from the workpiece 38 is "peeled out".
• an outer contour is generated on the workpiece 38 with the aid of the power skiving tool 10 in the manner mentioned, which, viewed in cross section, corresponds to a regular hexagon.
• Such an outer contour corresponds, for example, to the outer contour of a hexagon on a screw or a bolt.
• the flat surfaces of the hexagonal profile are generated with the aid of the teeth 18, which have the previously described flat and comparatively slightly curved, convexly rounded contour.
• the corners of the hexagonal profile are, however, generated with the aid of the transition contours between the teeth 18 or with the spaces between the teeth, which results in more or less exact corners on the workpiece 38.
• the workpiece 38 is preferably rotated at a higher speed than the skiving tool 10.
• a speed ratio of 3: 1 can be provided, for example.
• the power skiving tool 10 can be rotated at a speed in the range of 3,000 rpm, while the workpiece 38 is rotated at a speed in the range of 12,000 rpm.
• the axis crossing angle ⁇ which is only shown schematically in FIG. 9, can be, for example, 25 °.
• the cutting speed can be set to 100 m / min.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Geometry (AREA)
• Gear Processing (AREA)
• Milling Processes (AREA)
• Turning (AREA)

Applications Claiming Priority (2)

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• 2019
  • 2019-12-20 DE DE102019135435.8A patent/DE102019135435A1/de active Pending
• 2020
  • 2020-10-19 MX MX2022006268A patent/MX2022006268A/es unknown
  • 2020-10-19 CN CN202080089880.8A patent/CN114867573A/zh active Pending
  • 2020-10-19 WO PCT/EP2020/079368 patent/WO2021121730A1/de unknown
  • 2020-10-19 EP EP20793657.6A patent/EP4076808A1/de active Pending
  • 2020-10-19 JP JP2022537565A patent/JP7407942B2/ja active Active
• 2022
  • 2022-05-11 US US17/741,731 patent/US20220266364A1/en active Pending

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