Method for manufacturing a rotary cutting tool

Abstract

A method for manufacturing a rolling tool with cutting teeth is provided, the method including the steps of: determining a tooth profile to be formed using the rolling tool to create a tooth portion from a workpiece; determining a cutting tooth geometry including cutting edges of the cutting tooth geometry that can form the determined tooth profile formed from the workpiece by a rolling process; dividing the cutting tooth geometry into at least two different partial cutting tooth geometries, the different partial cutting tooth geometries being formed such that at least one of the partial cutting tooth geometries has a segment that recedes behind the outer contour of the cutting tooth geometry and such that an overlap between the different partial cutting tooth geometries reproduces the cutting tooth geometry; providing a rolling tool blank; and forming cutting teeth having the different partial cutting tooth geometries from the rolling tool blank. The method also includes the steps of a rolling tool and a method for creating a tooth portion using the rolling tool.

Description

[Technical Field]

[0001] The present invention provides Rotary cutting Tool manufacturers By law Regarding. [Background technology]

[0002] Rotary cutting Machining methods, in particular the hobbing method and the skiving method known from patent document 1, play an important role in producing teeth by cutting. Rotary cutting With the aid of a tool, inter-tooth gaps are formed in the workpiece blank in a series of cutting processes in which the cutting teeth each remove chips of material, usually from the workpiece blank, thereby producing teeth, where a given machining geometry is defined by the contour shape of the cutting edges, hereinafter referred to as the cutting tooth geometry. Rotary cutting The shape of the cutting teeth of the tool is predetermined by the shape of the intertooth gap to be formed in the work blank.

[0003] Basically, all Rotary cutting In machining processes, the achievable precision and the surface quality of the produced teeth are influenced by chip formation. Up until now, attempts have been made to optimize precision and quality, particularly by improving the cutting teeth. For example, attempts have been made to use rounded teeth to minimize the uncontrolled force action of the teeth and to obtain tools with improved service life. However, this has proven to create new problems, particularly with regard to the precise positioning of the teeth and the start of the cut of the mating teeth. The sliding of the teeth on the material being cut and / or the "peeling" of the material leads to indeterminate surface texture, and in addition, the "peeling" and the pressing of the teeth against the material result in undesirable heat input and friction losses associated with this. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] German Patent No. 243514 Summary of the Invention

[0005] Therefore, the object of the present invention is to improve the quality of the teeth. Rotary cutting Tool manufacturers The law The purpose is to provide.

[0006] The above problem is solved by a method having the features of claim 1. By law So it is solved 。

[0007] Equipped with cutting teeth Rotary cutting The method according to the invention for producing a tool particularly comprises the steps already required up to now, namely: - Rotary cutting determining a tooth profile to be formed from a workpiece using a tool; - A predetermined tooth profile formed to create a tooth portion from a workpiece Rotary cutting determining cutting tooth geometries, including cutting edges of the cutting tooth geometries, that can be formed by the machining process; - Rotary cutting providing a tool blank; - Rotary cutting forming cutting teeth from the tool blank; Includes.

[0008] It is important to the present invention that the cutting tooth geometry is divided into at least two different partial cutting tooth geometries, and the different partial cutting tooth geometries are formed such that at least one of the partial cutting tooth geometries has a segment that recedes behind the outer contour of the cutting tooth geometry, and the overlap of the different partial cutting tooth geometries reproduces the cutting tooth geometry, preferably each of the partial cutting tooth geometries having these segments.

[0009] That is, each segment of the cutting edge of a cutting tooth geometry required to form a predetermined intertooth gap is a component of at least one partial cutting tooth geometry, but conversely, there is at least one partial cutting tooth geometry that does not have at least one of these segments. Preferably, at least a portion of the cutting edge of the cutting tooth geometry is missing in each of the partial cutting tooth geometries.

[0010] That is, the conventional technique of introducing a desired shape of inter-tooth gap into the workpiece. Rotary cutting In the present invention, the cutting edges of the identically shaped cutting teeth of the tool are distributed among several cutting teeth, at least one of which, preferably several of which, in addition to one or more such cutting edge segments, has further cutting edge segments located within the cutting tooth geometry whose contour is predetermined by the cutting edge.

[0011] In this case, when forming the cutting teeth, cutting teeth with various partial cutting tooth geometries may be used. Rotary cutting It is formed from a tool blank. That is, the compound produced by the present invention Rotary cutting The tool has cutting teeth of various shapes, and these cutting teeth are Rotary cutting When machining a workpiece using a tool, the tools are each at least partially engaged in succession to form tooth gaps with a defined tooth profile when creating teeth from the workpiece, which can be ensured, for example, by matching the ratio between the number of teeth on the tool and the teeth to be created, in which case material can be removed by cutting.

[0012] This can result in that only a portion of the already partially formed tooth profile of the respective tooth gap being formed is subsequently machined, i.e., material is removed only there, particularly when these cutting teeth interact with the workpiece at least several times, and in this case at least one segment of the tooth flank of the tooth gap already partially formed from the workpiece has a tooth profile that remains unmachined after completion.

[0013] Intuitively, one might think that dividing the cutting tooth geometry into partial cutting tooth geometries would increase the machining time. However, in practice, this has proven to be largely inappropriate. Rotary cutting The tool interacts with the workpiece being machined Rotary cutting Reducing the number or length of tooth flanks of the tool tooth flank segments has a positive effect on the machining speed, on the one hand reducing the force required during cutting and on the other hand improving the chip flow characteristics.

[0014] At the same time, this procedure can result in a significantly improved machining quality, especially with regard to the quality of the tooth flanks, which the inventors have realised is due to the change in the chip generation process that accompanies this splitting.

[0015] An improvement in machining quality, especially tooth surface quality, is brought about by the division of the cutting tooth geometry into partial cutting tooth geometries, which influences the engagement of the individual segments of the cutting edge when penetrating the material and allows for control of chip thickness or chip thickness variations in different sections of the chip.

[0016] In order to obtain a reliable prediction resulting in an optimized partial cutting tooth geometry, it is preferred if the method further comprises a step of calculating the theoretical material removal when the cutting tooth interacts with a predetermined cutting tooth geometry and / or the partial cutting tooth geometry interacts with the workpiece.

[0017] In particular, the compounds produced according to the present invention Rotary cutting Tool and method according to the present invention Rotary cutting By adapting the partial cutting tooth geometry of the tool in such a way that tooth surfaces capable of removing only very fine chips in (at least) one partial cutting tooth geometry are not used, and therefore cutting teeth with this partial cutting geometry are skipped in the cutting process being carried out, it can be ensured that the chips removed have a minimum thickness at every point.

[0018] In practice, this can be achieved by dividing the cutting tooth geometry into partial cutting tooth geometries and not using cutting edges or segments of cutting edges of cutting tooth geometries whose theoretical material removal falls below a predetermined limit value in the partial cutting tooth geometries.

[0019] According to a further advantageous embodiment of the method, cutting teeth with different partial cutting tooth geometries are provided. Rotary cutting The forming of the tool blank is carried out using a grinding machine with a standardized profile or a standard grinding machine, so that different cutting tooth profiles can be machined / produced using the same grinding machine, especially in line processing. This is less expensive than the previously common use of profile grinding machines, which are individually produced for each cutting tooth profile, and in addition, makes it easy to individualize cutting teeth with various partial cutting tooth geometries.

[0020] Rotary Cutting A method for producing a toothed portion on a workpiece by forming a tooth profile by a method according to the present invention Rotary cutting The tools are Rotary cutting The tool has cutting teeth with at least two different partial cutting tooth geometries, which together define a predetermined tooth profile formed from the workpiece. Rotary Cutting The cutting tooth geometries, including the cutting edges of the cutting tooth geometries, can be formed by the method, and the different partial cutting tooth geometries are formed such that when at least one cutting tooth having one of the partial cutting tooth geometries interacts with the workpiece, only a portion of the cutting edge of the cutting tooth geometry interacts with the workpiece.

[0021] The different partial cutting geometries are particularly preferred when the cutting teeth having the respective partial cutting tooth geometries are formed in such a way that when they interact with the workpiece, only a portion of the cutting edge of the cutting tooth geometry interacts with the workpiece.

[0022] Like this Rotary cuttingUsing a tool Rotary cutting In the method according to the invention for producing a toothed portion on a workpiece by forming a tooth profile by machining, when successively forming a predetermined gap between two teeth of the tooth profile, having different partial cutting tooth geometries Rotary cutting characterized in that the cutting teeth of the tool are successively used. This can be done, in particular, by adapting them when the number of teeth of the toothed portion and Rotary cutting the tool is appropriately selected.

[0023] The present invention will be described in detail below based on the drawings showing embodiments.

Brief Description of the Drawings

[0024] [Figure 1a] A view showing a workpiece having external teeth and a tool having a cutting tooth geometry capable of producing this toothed portion on the workpiece by a rotary cutting method. [Figure 1b] A view showing a workpiece having internal teeth and a tool having a cutting tooth geometry capable of producing this toothed portion on the workpiece by a rotary cutting method. [Figure 2a] A view showing a series of intermediate states when teeth are produced on the workpiece according to FIG. 1a using a rotary cutting tool having cutting teeth including the cutting tooth geometry according to FIG. 1a. [Figure 2b] A view showing a series of intermediate states when teeth are produced on the workpiece according to FIG. 1b using a rotary cutting tool having cutting teeth including the cutting tooth geometry according to FIG. 1b. [Figure 3a] A view showing the cutting tooth geometry of FIG. 1a and the possibility of division into two partial cutting tooth geometries according to the invention. [Figure 3b] A view showing the overlap of the two partial cutting tooth geometries of FIG. 3a. [Figure 4a] A view showing the cutting tooth geometry of FIG. 1b and the possibility of division into two partial cutting tooth geometries according to the invention. [Figure 4b] A view showing the overlap of the two partial cutting tooth geometries of FIG. 4a. [Figure 5a]3b shows a series of intermediate states when producing an external tooth on a workpiece according to FIG. 1a using a rotary cutting tool with cutting teeth in a partial cutting tooth geometry (divided) according to the present invention. [Figure 5b] 4b-4c show a series of intermediate states when producing an internal tooth on a workpiece according to FIG. 1b using a rotary cutting tool with (divided) cutting teeth in a partial cutting tooth geometry according to FIG. 4b. DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1a shows, on the left, a workpiece 1 with external teeth already fully introduced into the workpiece 1 by forming tooth gaps 1a, and, on the right, a workpiece 1 with a plurality of identical cutting teeth 101. Rotary cutting 1 shows a tool 100, the cutting teeth of which are defined by the contours of the cutting edges. As can be clearly seen in FIG. 1, the cutting teeth 101 are much narrower than the tooth gaps 1a, but the fact that the cutting teeth are able to introduce the tooth gaps 1a into the workpiece 1 means that the tooth gaps 1a are continuously cut into the workpiece 1. Rotary cutting Typical of processing methods Rotary cutting This is the result of the operation of the tool 100 on the workpiece 1.

[0026] FIG. 1b shows, on the right, a workpiece 2 with an internal tooth already fully introduced into the workpiece 2 by forming tooth gaps 2a, and, on the right, a workpiece 2 with a plurality of identical cutting teeth 201. Rotary cutting 1a and 1b, the cutting teeth geometry of the tool 200 is defined by the contours of the cutting edges. Rotary cutting The radius ratio of tool 2 is Rotary cutting This is much more similar than in the case of tool 1, whereby the width of the cutting teeth 201 is much more similar to the width of the tooth gap 2a.

[0027] 2a or 2b show a prior art cutting tooth geometry according to FIG. 1a or 1b only. Rotary cuttingA series of intermediate states are shown when using a tool to introduce a tooth into a workpiece according to Figure 1a or 1b. These illustrations are greatly enlarged, and the simulations shown here each show the formation of a tooth gap with a total depth of 4 mm, achieved by a series of approximately 80 cuts.

[0028] In that case, in Figure 2a, the tooth gap is gradually cut from right to left, so that after the cut to remove the first material, cutting line 11, and after the cut to remove the second material, cutting line 12, etc. form part of the workpiece surface. In Figure 2b, the tooth gap is gradually cut from left to right, so that after the cut to remove the first material, cutting line 21, and after the cut to remove the second material, cutting line 22, etc. form part of the workpiece surface.

[0029] Thus, each area between two adjacent cutting lines represents the tooth resulting from the next cut following in the direction of the root of the tooth gap, in its "ideal shape", i.e., free from chips while they are being removed. It can be seen that both in the case of the external tooth cut shown in Figure 2a and in the case of the internal tooth cut shown in Figure 2b, there are several cutting lines that are very closely spaced. Accordingly, from Figures 2a and 2b, it can be seen that, as is known from the prior art, Rotary cutting When creating tooth gaps with a tool, a large number of chips are generated, which have very small fragments and are therefore easily deformed during cutting, while also being cut inconsistently, which leads to suboptimal chip generation and, as a result, suboptimal tooth quality.

[0030] 3a and 3b show an example for dividing a cutting tooth geometry 30 for forming external teeth into two partial cutting tooth geometries 31, 32 according to the invention. Rotary cuttingThe tool has only cutting teeth whose cutting edges each include one of the partial cutting tooth geometries 31, 32, and these cutting teeth are arranged in such a way that successive cuts are made using cutting teeth of different partial cutting tooth geometries, although of course a division into more partial cutting tooth geometries can also be made if this proves to be meaningful, and in addition, as can be seen in particular in Figures 2a and 2b, the first chips to be cut do not yet have the problem of fine chip fragments, so that the cutting edges only include cutting teeth corresponding to the cutting tooth geometries. Rotary cutting It can also be provided on the tool.

[0031] 3a, cutting tooth geometry 30, partial cutting tooth geometry 31, and partial cutting tooth geometry 32 are shown offset from one another by a fixed offset. As can be seen in this figure, partial cutting tooth geometry 31 is created by shortening cutting tooth geometry 30 by its tip but has the sides of the cutting tooth geometry, while partial cutting tooth geometry 32 reproduces the tip of cutting tooth geometry 30 but with a narrower side area.

[0032] As can be seen in Figure 3b, where the partial cutting tooth geometries 31, 32 are shown superimposed on one another, the partial cutting tooth geometries 31 and 32 jointly reproduce the cutting tooth geometry 30, which corresponds to the outer contour of the superimposed partial cutting tooth geometries 31 and 32. Segments 31a and 31c of the partial cutting tooth geometry 31 form the sides of the cutting tooth geometry 30, and segment 32b of the partial cutting tooth geometry 32 forms the tip of the cutting tooth geometry 30.

[0033] Conversely, therefore, partial cutting tooth geometry 31 has a recessed segment 31b at the rear of cutting tooth geometry 30, and partial cutting tooth geometry 32 has recessed segments 32a, 32c at the rear of cutting tooth geometry 30.

[0034] Figures 4a and 4b show a similar situation of a cutting tooth geometry 40 introducing internal teeth and the associated partial cutting tooth geometries 41 and 42, respectively, with segments 41a, 41b, 41c or 42a, 42b, 42c, and therefore in this respect reference can be made to the description of Figures 3a and 3b, respectively, in which the reference numbers have been adapted.

[0035] However, it should be clearly emphasized that other divisions of the cutting tooth geometry 30, 40 into two or more partial cutting tooth geometries 31, 32, 41, 42 are also possible, and one partial cutting tooth geometry does not necessarily have to reproduce the tip and the second partial cutting tooth geometry the flank of the cutting tooth geometry.

[0036] The effect of this measure can be seen in Figures 5a and 5b, which show a series of intermediate states represented by cutting lines 51, 52, 61, 62, respectively, when introducing external or internal teeth into workpieces 1 or 2, as in Figures 2a and 2b. However, unlike Figures 2a and 2b, here, in the illustrated example, cutting teeth with partial cutting tooth geometry 31 or 41 and cutting teeth with partial cutting tooth geometry 32 or 42, respectively, are used alternately. Rotary cutting The tool has different types of cutting teeth, including partial cutting tooth geometries 31, 32 or 41, 42. Rotary cutting The total tooth depth and feed are then the same as in Figure 2a or 2b.

[0037] It is immediately apparent that the areas where only very fine chips are removed have been significantly reduced. In these areas, a consistent chip formation can be expected, which results in a significantly higher tooth quality. [Explanation of symbols]

[0038] 1, 2...Work 100, 200... Rotary cutting tool 101, 201...Cutting teeth 1a, 2a...Interdental space 11, 12, 21, 22, 51, 52, 61, 62...cutting line 30, 40...Cutting tooth geometry 31, 32, 41, 42...Partial cutting tooth geometry 31a, 31b, 31c, 32a, 32b, 32c...segments of partial cutting tooth geometry 41a, 41b, 41c, 42a, 42b, 42c...segments of partial cutting tooth geometry

Claims

[Claim 1] A method for manufacturing a rotary cutting tool (100, 200) with cutting teeth (101, 201), comprising the steps of: - determining a tooth profile to be formed to produce a tooth portion from the workpiece (1, 2) using said rotary cutting tool (100, 200); - determining a cutting tooth geometry (30, 40) including the cutting edges of said cutting tooth geometry (30, 40) that allows the defined tooth profile to be formed from said workpiece (1, 2) by a rotary cutting method; - dividing the cutting tooth geometry (30, 40) into at least two different partial cutting tooth geometries (31, 32, 41, 42), the different partial cutting tooth geometries (31, 32, 41, 42) being formed in such a way that at least one of the partial cutting tooth geometries (31, 32, 41, 42) has a segment (31b, 32a, 32c, 41b, 32a, 32c) located inside the contour of the cutting tooth geometry (30, 40) and such that the overlap of the different partial cutting tooth geometries (31, 32, 41, 42) reproduces the cutting tooth geometry (30, 40); - providing a rotary cutting tool blank; - forming cutting teeth (101, 201) with said different partial cutting tooth geometries (31, 32, 41, 41) from said rotary cutting tool blank; calculating the amount of material that would theoretically be removed when a cutting tooth (101, 201) having a predetermined cutting tooth geometry (30, 40) and / or a predetermined partial cutting tooth geometry (31, 32, 41, 42) interacts with the workpiece (1, 2), When dividing the cutting tooth geometry (30, 40) into the partial cutting tooth geometries (31, 32, 41, 42), a segment of at least one partial cutting tooth geometry (31, 32, 41, 42) corresponding to a segment of the cutting tooth geometry (30, 40) whose theoretical amount of material removed when interacting with the workpiece (1, 2) is below a predetermined lower limit value but greater than zero is positioned inside the contour of the cutting tooth geometry.

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