Method for enabling or improving the pullability of a bevel gear, a suitably equipped device and a suitably modified transmission

Abstract

Method for enabling or improving the pullability of a first bevel gear (20) which together with at least one second bevel gear (30) is to form a transmission (10) which is to be mounted in a housing (11) in such a way that a rotary motion (ω1) of the first bevel gear (20) can be transmitted into a rotary motion (ω2) of the second bevel gear (30), or vice versa, comprising the following steps: - Performing a drawability procedure (ZV) with the following sub-steps (TS1, TS2): o Calculating whether, during assembly in the housing (11), the first bevel gear (20) can be brought into engagement with the second bevel gear (30) by an axial insertion movement and / or whether the first bevel gear (20) can be separated from engagement with the second bevel gear (30) by an axial pulling movement, o if the calculation results in a collision during engagement or separation between a tooth (22) of the first bevel gear (20) and a tooth (32) of the second bevel gear (30), ▪ Computational determination of a flank modification (FM) on the teeth of the first bevel gear (20) or the second bevel gear (30) to avoid collision, ▪ Determining second machine data (MD2) based on this flank modification (FM), - Performing a post-processing operation in a bevel gear cutting machine (100) to carry out the flank modification (FM) according to the second machine data (MD2) on the existing teeth (22) of the first bevel gear (20) or on the existing teeth (32) of the second bevel gear (30).

Description

[0001] The present invention relates to the drawability of bevel gears in a bevel gear transmission. It also relates to a device comprising a gear cutting machine and a correspondingly equipped development environment. Furthermore, it relates to a correspondingly modified bevel gear transmission. State of the art

[0002] The document WO 2006 / 133 727 A1 describes a method for optimising the surface geometry of bevel or hypoid gears for their production on a free-form machine.

[0003] Document EP 2 485 170 A2 describes a method for generating a design drawing for a design variant, wherein this design variant is composed of components of a construction kit, wherein a computer system uses a parts list for the design variant to determine a command sequence for generating a CAD drawing or a 3D model of the design variant.

[0004] The document KLINGELNBERG J.: Bevel Gears. Berlin Heidelberg : Springer-Verlag, 2008, ISBN 978-3-540-71860-4 describes processes for the manufacture and design of bevel gears.

[0005] The document "Gear Design Innovation" in: Transmission Technology International, 2013, describes processes for the manufacturing and design of bevel gears.

[0006] There are different types of bevel gears. Each of these bevel gears comprises at least two bevel gears that mesh with each other. Bevel gears are also called angular gears because the rotational axes of the two bevel gears are at an angle to each other.

[0007] In Fig. 1 shows a perspective view of details of an exemplary (bevel gear) transmission 10, such as is used in a crusher. The housing of this transmission 10 is not shown here. Two bevel gears 20, 30 are used, which are mounted in the housing (not shown) such that they are in engagement. The first bevel gear 20 (here a pinion) is mounted on a shaft 21, and the second bevel gear 30 (here a ring gear) is mounted on a shaft 31. In Fig. 1, the arcuate teeth 22 of the first bevel gear 20 and the arcuate teeth 32 of the second bevel gear 30 can be seen.

[0008] In Fig. 2 shows a side view of details of a similarly constructed (bevel) gear 10. This illustration is highly schematic. A rectangular housing 11 is used, in which two bevel gears 20, 30 are mounted so that they are in engagement. On the side of the housing 11, for example, an assembly / inspection opening can be provided, which here is sealed oil-tight with a plate 12 and a suitable seal (not shown). During assembly, the second bevel gear 30 can first be inserted into the housing 11 through the assembly / inspection opening and there can be screwed or plugged together, for example, with a shaft stub or a shaft 31. Then, the first bevel gear 20 is pushed in the axial direction, ie parallel to the first shaft 21, through the assembly / inspection opening into the housing 11, taking care that the teeth of the first bevel gear 20 are brought into clean engagement with the teeth of the second bevel gear 30.The corresponding bearings and seals for shafts 21 and 31 are not shown here. After completing the assembly steps mentioned above, oil can be added and the plate 12, including the seal, can be attached to the housing 11.

[0009] Disassembly typically takes place in the reverse order of the steps mentioned above.

[0010] During both assembly and disassembly, the teeth of the two bevel gears can collide. This type of collision occurs primarily with helical and spiral-toothed bevel gears. In practice, a hammer is sometimes used when inserting the first bevel gear 20 to overcome the mechanical resistance that can result from such a collision, even if this procedure is not professional. It is also known to use an angle grinder, for example, to remove parts of the tooth flanks of one or two teeth of the first bevel gear 20, so that they no longer collide and jam during insertion.

[0011] It's obvious that such approaches have disadvantages. Grinding or grinding away parts of a tooth flank weakens that tooth. This reduces the ability to transfer load from one bevel gear to the other. This can lead to cracking and failure of the affected tooth. Furthermore, removing material from one or two teeth leads to imbalance, which in turn can affect smooth running.

[0012] Even if after grinding or grinding away no further problems should arise when inserting the first bevel gear 20, since one can ensure during insertion that the first bevel gear 20 with the modified tooth(s) is brought into exact engagement with the tooth gaps of the second bevel gear 30 in a suitable angular position, separating (also called pulling) the two bevel gears 20, 30 can still be difficult or even impossible if one cannot find the same angular position again.

[0013] To avoid the problems mentioned above when assembling or pulling bevel gears in a bevel gear transmission, the pullability can be taken into account from the outset when designing the transmission. In some cases, it is possible to prevent jamming from the outset by making a small adjustment to the macrogeometry of the two bevel gears in the bevel gear transmission. For example, if the spiral tooth flanks have a radius of curvature that is too tight, a gear cutting tool with a larger nominal tool radius can be used for gear cutting. The larger nominal radius results in a less curved tooth flank and thus also a lower tendency to jam. However, especially for large-module bevel gears, such as those used in stone mills and the like, gear cutting tools with a sufficiently large nominal tool radius are not available.In addition, such changes in macrogeometry are often “bought” at the cost of a reduced degree of cover and, consequently, a reduced load-bearing capacity.

[0014] Therefore, there are always situations in which an adjustment of the macrogeometry does not enable drawability or in which the computationally determined adjustment of the macrogeometry is undesirable.

[0015] The task therefore arises to find a way to reliably enable the pullability when separating two bevel gears without relying on manual post-processing.

[0016] The object is achieved according to the invention by a method according to claim 1, a device according to claim 7, and a bevel gear transmission according to claim 9. Advantageous embodiments of the invention form the subject matter of the dependent claims.

[0017] The method according to the invention was specifically developed to enable or improve the pullability of a first bevel gear which, together with at least one second bevel gear, is to form a gear, wherein the gear is to be mounted in a housing in such a way that a rotational movement of the first bevel gear can be transmitted into a rotational movement of the second bevel gear, or vice versa.

[0018] The method of the invention comprises the following steps: - Carrying out a drawability procedure with the following sub-steps: o calculating whether, during assembly in the housing, the first bevel gear can be brought into engagement with the second bevel gear by an axial insertion movement and / or whether the first bevel gear can be separated from the engagement with the second bevel gear by an axial pulling movement, o if the calculation results in a collision during engagement or separation between a tooth of the first bevel gear and a tooth of the second bevel gear, ▪ Calculating a flank modification on the teeth of the first or second bevel gear to avoid the collision, ▪ Determination of second machine data based on this flank modification, - carrying out a gear cutting operation in the bevel gear cutting machine in order to provide the first or the second bevel gear with a toothing according to first machine data; - Carrying out a post-processing operation in the bevel gear cutting machine in order to carry out the flank modification according to the second machine data on the existing teeth of the first or second bevel gear.

[0019] In all embodiments, the post-processing in the bevel gear cutting machine can be carried out as a continuously dividing post-processing or as a discontinuous dividing post-processing (also called single-part process).

[0020] Preferably, in all embodiments, in a preparatory method step which takes place before the first machine data are determined, design data for the first or the second bevel gear are provided, wherein the first machine data are then derived from these design data.

[0021] Preferably, in all embodiments, the preparatory method step is carried out in a development environment equipped with software for designing a transmission.

[0022] In all embodiments, the development environment preferably comprises a computer equipped with software for designing gears.

[0023] The invention is also achieved by a (complete) device comprising a CNC-controlled gear cutting machine and a development environment, wherein the development environment can be brought into communication with the gear cutting machine. The gear cutting machine comprises a CNC control and several CNC-controlled axes in order to provide a bevel gear with a toothing based on machine data within the framework of a continuous gear cutting process. The (complete) device is characterized in that - the development environment is equipped with software for designing a gear with a first bevel gear and a second bevel gear to be paired with it, in order to be able to provide design data for the first and / or the second bevel gear within the scope of this design; - the development environment is designed to carry out a drawability procedure in order to calculate a flank modification on the teeth of the first or second bevel gear within the scope of this drawability procedure in order to avoid a collision of the teeth of the first bevel gear with the teeth of the second bevel gear during installation or removal, - the development environment provides second machine data when carrying out the drawability process, which can be used in the gear cutting machine for the CNC-controlled remachining of the teeth of the first or second bevel gear.

[0024] The invention enables a partially automated machining of at least one bevel gear of a bevel gear transmission in order to improve or enable the pullability.

[0025] According to the invention, the penetration area is removed in a targeted and precise manner using modified machine (setting) data (here referred to as second machine data). Preferably, the machining post-processing process uses a continuous milling or grinding process.

[0026] The post-processing used for flank modification can be used in all designs, e.g. on the thrust flanks of ring gears, if the gearbox is only to be used in traction operation.

[0027] The invention delivers reproducible and reliable results. A bevel gear that has been improved / optimized with the invention with regard to the pullability of all teeth of one of the bevel gears exhibits no imbalance, as is the case with bevel gears in which one of the pairing bevel gears has been manually reworked.

[0028] It is an advantage of the invention that a reproducible, since measurable, post-processing results.

[0029] Since the remachining is applied to all right and / or all left flanks of one of the two bevel gears, the pullability is ensured in any meshing position of the gear set.

[0030] The invention has the advantage that the load-bearing capacity of the teeth can be taken into account when carrying out the pullability process in order to avoid excessive local weakening of the teeth.

[0031] The invention has the advantage that even with large and heavy bevel gears, the bevel gear pinion can be pulled axially during disassembly without the need for an axial (lowering) movement of the ring gear.

[0032] The invention can be used in both continuous and discontinuous dividing processes on CNC-controlled gear cutting machines. Bevel gear milling machines and bevel gear grinding machines with at least five CNC-controlled axes are particularly suitable.

[0033] According to the invention, the post-machining for the purpose of flank modification can be carried out on the soft bevel gear (i.e. before hardening) or on the hardened bevel gear.

[0034] The invention is particularly suitable for industrial gears and for gears characterized by a high load capacity and for gears that have a module > 10.

[0035] The list of reference symbols is part of the disclosure. DRAWINGS

[0036] The figures are described in a coherent and comprehensive manner. Embodiments of the invention are described in more detail below with reference to the drawings. They show: Fig. 1 shows a schematic perspective view of an exemplary gearbox designed, for example, as part of the drive of a crusher; Fig. Figure 2 shows a highly schematic side view of an exemplary gearbox, which is mounted here in a rectangular housing; Fig. 3 shows a highly schematic perspective view of another exemplary gearbox, which is here mounted in a rectangular housing; Fig. Figure 4 shows a schematic flow diagram with the essential steps of the method of the invention; Fig. 5 shows a schematic flow diagram with further steps of the method of the invention; Fig. 6 a schematic block diagram of an (overall) device according to the invention; Fig. Figure 7 shows a schematic view of a curved tooth of a bevel gear in radial projection, in which the penetration area has been shown; Fig. Figure 8 shows a schematic perspective view of some curved teeth of a bevel gear modified according to the invention (in the example shown, the concave thrust flanks of a ring gear were modified). Detailed description

[0037] In connection with this description, terms are used that are also used in relevant publications and patents. However, it should be noted that the use of these terms is intended solely to facilitate understanding. The inventive concept and the scope of protection of the patent claims are not intended to be limited in interpretation by the specific choice of terms. The invention can be readily applied to other terminology systems and / or technical fields. In other technical fields, the terms are to be applied analogously.

[0038] In most cases, axial tensile motion is defined as the superposition of rotational and tensile motion. The term "axial tensile motion" is intended to indicate that the tensile motion includes a distinct axial component. An "axial insertion motion" is in most cases the superposition of rotational and shear motion.

[0039] In Fig. Figure 2 shows a side view of details of an exemplary (bevel) transmission 10. This illustration is schematic. As mentioned above, the transmission 10 comprises two paired bevel gears 20, 30.

[0040] A rectangular housing 11 is used, in which the two bevel gears 20, 30 are mounted (paired with each other) in such a way that they are in engagement. A mounting / inspection opening can be provided on the side of the housing 11, which is sealed oil-tight here with a plate 12 and a suitable seal (not shown). During disassembly, the mounting / inspection opening on the housing 11 is first opened and the oil is drained (partially or completely). Then, the first bevel gear 20 can be pulled out of the housing 11 through the mounting / inspection opening in the axial direction, i.e., parallel to the rotational axis R1 of the first shaft 21. The pulling is in the Fig. 2 and Fig. 3, each represented by a block arrow with the reference symbol Z1. In most cases, a rotational movement is superimposed on the axially directed pulling movement Z1 in order to separate the two bevel gears 20, 30. In most cases, the second bevel gear 30 (of the ring gear) is rotated slightly around the rotation axis R2, while the first bevel gear 20 (the pinion) is pulled.

[0041] If the second bevel gear 30 needs to be repaired or replaced, it can be unscrewed and removed through the assembly / inspection opening in the housing 11. However, the second bevel gear 30 can also be removed through another opening in the housing 11, e.g., by axially lowering it, which is only possible with considerable effort with extremely heavy crown gears. Often, the installation situation also does not allow the second bevel gear 30 to be lowered, meaning that in these cases, the first bevel gear 20 must be removed by pulling it in the axial direction.

[0042] If one of the bevel gears 20 or 30 has been modified according to the invention, the pulling Z1 can take place without problems and without clamping the teeth 22, 32 of the two bevel gears 20, 30.

[0043] In the Fig. 3 shows a schematic perspective view of another exemplary (bevel) gear 10. In the example shown, both bevel gears 20, 30 each have a shaft 21, 31, the ends of which protrude from the housing 11. When the first bevel gear 20 is driven clockwise, as in Fig. 3 by the arrow ω1, the second bevel gear 30 rotates counterclockwise, as shown by the arrow ω2. The direction of rotation is defined here with a view along the rotation axes R1, R2.

[0044] In order to enable or simplify the assembly and disassembly explained with reference to several exemplary figures, a method is proposed, the essential aspects of which are explained below with reference to the flow charts of the Fig. 4 and Fig. 5 are described.

[0045] Preferably, in a first step S1, first machine data MD1 are provided. This data MD1 can, for example, be loaded from a memory area 51 or provided by software SW1. The machine data MD1 are used for the CNC-controlled control of a bevel gear cutting machine 100 (see, for example, Fig. 6) when cutting the first bevel gear 20 or the second bevel gear 30. The individual CNC-controlled movements of the axes of the bevel gear cutting machine 100 are defined in the machine data MD1.

[0046] The machine data MD1 can be transferred to the bevel gear cutting machine 100 in an (intermediate) step, as in Fig. 4 is indicated by step S2. In Fig. 4, step S2 is represented merely by an interface or boundary point to the CNC control 101 of the bevel gear cutting machine 100.

[0047] In an essential method step of the invention, a pullability method ZV is now performed. The method step ZV uses either the machine data MD1 or the design data AD of the transmission 10. However, the pullability method ZV can also use a combination of the machine data MD1 and the design data AD. Fig. 4, it is therefore indicated by a node 52 that the machine data MD1 and the design data AD can be merged.

[0048] In Fig. 4, the drawability method ZV is shown merely as a process, designated by the reference symbol ZV. As a result, the drawability method ZV delivers machine data MD2 or—in a modified embodiment of the invention—modified first machine data MD1 in a step S3.

[0049] The machine data MD2, or if necessary the changed first machine data MD1, can be transferred to the bevel gear cutting machine 100 in an (intermediate) step, as in Fig. 4 is indicated by step S4. In Fig. 4, step S4 is represented merely by an interface or boundary point to the CNC control 101 of the bevel gear cutting machine 100.

[0050] In Fig. 5 shows exemplary details of a particularly preferred drawability method ZV of the invention.

[0051] The ZV drawability procedure can include, for example, the following sub-steps: Calculating whether, during assembly in the housing 11, the first bevel gear 20 can be brought into engagement with the second bevel gear 30 by an axial insertion movement and / or whether the first bevel gear 20 can be separated from engagement with the second bevel gear 30 by an axial pulling movement. In order to be able to determine a collision between the two bevel gears 20, 30 during assembly or disassembly, the design data AD of the gearbox 10 are preferably evaluated mathematically. In particular, the exact flank geometry and installation position must be known in order to be able to determine a collision between the two bevel gears 20, 30. This means that the design data AD used here should, in particular, contain information on the flank geometry and installation position. The design data AD can, for example, be loaded from a memory area 53, as in Fig. 5. In all embodiments, the memory areas 51 and 53 can be provided in one and the same memory (e.g., in the memory 102).

[0052] TS1. If the computational determination in step TS1 results in a collision during engagement or disengagement between a tooth 22 of the first bevel gear 20 and a tooth 32 of the second bevel gear 30, steps i. and ii. follow: i. Calculating a flank modification FM on the teeth 22 of the first bevel gear 20 or on the teeth 32 of the second bevel gear 30 in order to avoid the collision, ii. Determination of second machine data MD2 based on this flank modification FM.

[0053] In all embodiments of the invention, step TS2 i. can be based on a calculation approach in which, for example, the outlines of the second bevel gear 30 are statically defined in a coordinate system and in which, for example, the outlines of the first bevel gear 20 are moved relative to the second bevel gear 30 (e.g., by a successive coordinate transformation). In most cases, both bevel gears 20, 30 must be rotated while, for example, the first bevel gear 20 is axially displaced. In these cases, the relative movement comprises a superposition of rotational and linear movements. This relative movement (which here occurs computationally in the virtual realm) results in a type of collision region in the three-dimensional coordinate system. In all embodiments of the invention, this collision region preferably corresponds to the penetration region of the solid body of the first bevel gear 20 with the solid body of the second bevel gear 30.

[0054] Based on this penetration area, a flank modification FM of the tooth flanks of the teeth 22 of the first bevel gear 20 or the teeth 32 of the second bevel gear 30 can now be determined mathematically.

[0055] In all embodiments of the invention, step TS2 ii. can define the second machine data MD2 such that, when executing the corresponding CNC-controlled movements in the bevel gear cutting machine 100, the required flank modifications FM can be performed on the tooth flanks of the teeth 22 of the first bevel gear 20 or on the tooth flanks of the teeth 32 of the second bevel gear 30 by machining.

[0056] If the computational determination in step TS1 does not result in a collision, the pullability procedure ZV branches via an interface SS1 of the Fig. 5 back to Fig. 4. In this case, the first or second gear 20 or 30 is produced without flank modification FM, or no post-processing is required in the bevel gear cutting machine 100 to perform a flank modification FM.

[0057] Before or during the method of the invention, a continuously indexing or discontinuously indexing gear cutting operation is performed in the bevel gear cutting machine 100 to provide the first bevel gear 20 or the second bevel gear 30 with a toothing according to the first machine data MD1. It is not essential to the invention when this gear cutting operation is performed.

[0058] As part of the method of the invention, a continuously indexing or discontinuously indexing post-machining operation is performed in bevel gear cutting machine 100 to perform the flank modification FM according to the second machine data MD2 on the already existing teeth 22 of the first bevel gear 20 or on the already existing teeth 32 of the second bevel gear 30. This post-machining step is always performed after the original tooth cutting of the corresponding bevel gear 20 or 30. This means that the bevel gear 20 or 30 to be reworked has already been (pre-)toothed.

[0059] Fig. 6 shows a schematic block diagram of an (overall) device 200 according to the invention.

[0060] The (overall) device 200 comprises at least one CNC-controlled gear cutting machine 100 and a development environment 50, wherein the development environment 50 can be brought into a communication connection 54 with the gear cutting machine 100. In Fig. In Figure 6, this communication connection 54 is represented by a block arrow. In all embodiments, it can be, for example, a (company-internal) communication network that connects the gear cutting machine 100 to the development environment 50.

[0061] The gear cutting machine 100 comprises a CNC control 101 and several CNC-controlled axes X, Y, Z, B, R1, R2 (the number of these CNC-controlled axes and their axis designations are only an example). Fig. In Figure 6, each of the axes is represented by a block, and each of these blocks is connected to the CNC controller 101 by a double-headed arrow. This schematically indicates that the CNC controller 101 controls the individual axes and that the axes can send signals (e.g., signals or data from position sensors or angle sensors) back to the CNC controller 101.

[0062] The gear cutting machine 100 may include an internal and / or external memory 102, as shown in Fig. 6. The memory 102 can be connected to the CNC control 101 via a communication connection 103. The memory 102 can optionally be loaded with data (e.g., with the machine data MD1) via a further communication connection 104.

[0063] In order to be able to provide the first bevel gear 20 or the second bevel gear 30 with a toothing using the first machine data MD1 as part of a continuous gear cutting process, the first machine data MD1 is loaded, for example, from the memory 102 via the communication link 103 into the CNC control 101 so that the CNC control 101 can perform the continuous, cutting gear cutting on the corresponding bevel gear 20, 30 step by step. Such methods for gear cutting are well known and will therefore not be explained in detail here.

[0064] In all embodiments of the invention, the development environment 50 is preferably equipped with a software SW1 which is designed to design a transmission 10 with a first bevel gear 20 and a second bevel gear 30 to be paired therewith.

[0065] In all embodiments of the invention, the development environment 50 can be equipped with means 55 for (manual) input of data D1. The data D1 can, for example, include the basic information required for a design process that is necessary for defining a transmission 10.

[0066] From this data D1, the software SW1 can calculate and provide design data AD1 for the first bevel gear 20 as part of a design process. This design data AD1 can either be converted into machine-specific machine data MD1 in the development environment 50, or this conversion takes place in the gear cutting machine 100 itself (there, for example, using a software module SW2).

[0067] Preferably, the development environment 50 is designed in all embodiments to carry out a draggability method ZV. For this purpose, the development environment 50 can comprise, for example, a software module ZV, as in Fig. 6. In all embodiments, the software module ZV can provide modified design data AD1* and transmit them to the gear cutting machine 100 for conversion into machine data MD2, or the software module ZV can provide machine data MD2 in all embodiments, as shown in the example of Fig. 6. The provision of modified design data AD1* is not included in Fig. 6 shown.

[0068] The machine data MD1 and / or MD2 can be transferred from the software module SW2 to the memory 102, as schematically indicated by the communication connection 105, and / or the machine data MD1 and / or MD2 can be transferred directly (e.g., from the development environment 50) to the CNC controller 101, or they can be transferred from the software module SW2 to the CNC controller 101, as schematically indicated by the communication connection 106.

[0069] In all embodiments, the ZV software module can also be executed on a computer of the gear cutting machine 100. In this case, the aforementioned development environment 50 is part of the machine 100.

[0070] In all embodiments, the ZV software module is designed to computationally determine a flank modification FM on teeth 22 of the first bevel gear 20 or the second bevel gear 30 within the framework of the aforementioned ZV pullability method. This flank modification FM is determined in such a way that a collision of the teeth 22 of the first bevel gear 20 with the teeth 32 of the second bevel gear 30 is avoided during installation or removal.

[0071] After the computer-based execution of the drawability method ZV, the second machine data MD2 (or, in an alternative embodiment, the modified design data AD1*) are provided directly or indirectly. These second machine data MD2 are defined such that they can be used in the gear cutting machine 100 for the CNC-controlled remachining of the teeth 22 of the first bevel gear 20 or the teeth 32 of the second bevel gear 30.

[0072] In all embodiments, the drawability method ZV preferably also takes into account information on the counter flank clearance when determining the flank modification FM.

[0073] In the Fig. 7, the tooth flank 23 of a tooth 22 of an exemplary first bevel gear 20 is shown in a purely schematic form in a view in radial projection. On the left, in Fig. 7 the toe Z and on the right the heel F of the first bevel gear 20. The tooth tip 24 is at the top and the tooth base at the bottom. In the upper right corner in the heel area, the result of a computationally performed drawability method ZV is shown using several lines. The smaller and finer the dots or lines of the lines are, the less strong the penetration of the two solid bodies of the first bevel gear 20 and the second bevel gear 30. The longer the lines of the lines are, the stronger / deeper the penetration. In practice, a different type of representation can be chosen that is more descriptive than the representation in Fig. 7.

[0074] The ZV software module can assign a material removal rate to these lines. If, during post-processing, material is removed from tooth flanks 23, for example, according to the calculated material removal rate, collisions or jamming are avoided during axially aligned assembly or disassembly.

[0075] To illustrate this with a concrete example, Fig. 8 shows a section of a second bevel gear 30, whose teeth 32 have been provided with a flank modification FM. On the left, Fig. 8 shows the toe Z and, on the right, the heel F of the second bevel gear 30. Flank modifications FM are provided on the concave tooth flanks 33 in the transition area between the tooth tip 34 and the heel F.

[0076] As in Fig.8, which shows the result of post-processing according to the invention, the penetration area is removed in a targeted and precise manner by means of a machining post-processing process using modified machine (setting) data (here called second machine data MD2).

[0077] The simplest form of post-processing results from overlaying a previously created bevel gear geometry with the original target geometry of the tooth gap. By selecting the appropriate plunge position in conjunction with a gear rotation adjusted to the penetration depth, the "interfering" material portion can be removed very precisely from the flanks 33 of the bevel gear 30.

[0078] Alternatively, a modified rolled geometry can be superimposed on the original geometry of the bevel gear for post-machining purposes. List of reference symbols 10 gearboxes 11 housings 12 plates 20 first bevel gear 21 Wave 22 teeth 23 tooth flanks 24 tooth head 30 second bevel gear 31 Wave 32 teeth 33 tooth flanks 34 tooth head 50 development environment 51 Memory area 52 knots 53 Memory area 54 Communication connection 55 means of entering data 100 bevel gear cutting machines 101 CNC control 102 memory 103 Communication connection 104 Communication connection 105 Communication connection 200 (total) device AD, AD1 design data B Swivel axis D1 data F Heel FM flank modification i., ii. Steps MD1 first machine data MD2 second machine data R1 Rotation axis of the first shaft R2 rotation axis of the second shaft S1, S2, steps SS1 interface SW1 Software (module) SW2 software module TS1, TS2 (partial) steps ω1, ω2 rotational movements Z toe Z1 Pull / move ZV drawability procedure / software module X, Y, Z linear axes

Claims

[1] Method for enabling or improving the pullability of a first bevel gear (20) which, together with at least one second bevel gear (30), is to form a gear (10) which is to be mounted in a housing (11) in such a way that a rotary movement (ω1) of the first bevel gear (20) can be transmitted into a rotary movement (ω2) of the second bevel gear (30), or vice versa, comprising the following steps: - Carrying out a drawability procedure (ZV) with the following sub-steps (TS1, TS2): o calculating whether, during assembly in the housing (11), the first bevel gear (20) can be brought into engagement with the second bevel gear (30) by an axial insertion movement and / or whether the first bevel gear (20) can be separated from the engagement with the second bevel gear (30) by an axial pulling movement, o if the computational determination results in a collision during engagement or separation between a tooth (22) of the first bevel gear (20) and a tooth (32) of the second bevel gear (30), ▪ Calculating a flank modification (FM) on the teeth of the first bevel gear (20) or the second bevel gear (30) in order to avoid the collision, ▪ Determination of second machine data (MD2) based on this flank modification (FM), - carrying out a post-processing in a bevel gear cutting machine (100) in order to carry out the flank modification (FM) according to the second machine data (MD2) on the already existing teeth (22) of the first bevel gear (20) or on the already existing teeth (32) of the second bevel gear (30). [2] Method according to claim 1, characterized bythat in a preparatory method step, design data (AD) for the first bevel gear (20) and / or the second bevel gear (30) are provided and wherein first machine data (MD1) are determined or provided from these design data (AD). [3] Method according to claim 2, characterized by that based on the first machine data (MD1) in the bevel gear cutting machine (100) a pre-machining of the teeth (22) of the first bevel gear (20) or the teeth (32) of the second bevel gear (30) is carried out. [4] Method according to claim 2 or 3, characterized by that the preparatory method step is carried out in a development environment (50), preferably on a computer which is equipped with software (SW1) for designing the transmission (10). [5] Method according to claim 4, characterized by that the first machine data (MD1) are loaded into the bevel gear cutting machine (100). [6] Method according to one of claims 1 to 3, characterized by that the post-processing in the bevel gear cutting machine (100) is carried out on all teeth (22) of the first bevel gear (20) or on all teeth (32) of the second bevel gear (30). [7] Device (200) comprising a CNC-controllable gear cutting machine (100) and a development environment (50), wherein the development environment (50) can be brought into a communication connection (54) with the gear cutting machine (100), wherein the gear cutting machine (100) comprises a CNC control (101) and several CNC-controlled axes (X, Y, Z, B, R1, R2) in order to provide a bevel gear (20, 30) with a toothing on the basis of first machine data (MD1) within the framework of a continuous gear cutting process, characterized by , that - the development environment (50) is equipped with software (SW1) for designing a transmission (10) with a first bevel gear (20) and a second bevel gear (30) to be paired with it, in order to be able to provide design data (AD, AD1) within the scope of this design; - the development environment (50) is designed to carry out a drawability method (ZV) in order to computationally determine a flank modification (FM) on teeth (22) of the first bevel gear (20) or on teeth (32) of the second bevel gear (30) within the scope of this drawability method (ZV) in order to avoid a collision of the teeth (22) of the first bevel gear (20) with teeth (32) of the second bevel gear (30) during installation in the transmission (10) or during removal from the transmission (10), - the development environment (50) provides second machine data (MD2) when carrying out the drawability method (ZV), which second machine data can be used in the gear cutting machine (100) for the CNC-controlled remachining of the teeth (22) of the first bevel gear (20) or the teeth (32) of the second bevel gear (30). [8] Device (200) according to claim 7, characterized by that the gear cutting machine (100) is a bevel gear milling machine or a bevel gear grinding machine. [9] Bevel gear (10) with a housing (11), and a first bevel gear (20) and a second bevel gear (30), wherein these two bevel gears (20, 30) are in engagement with each other, arranged at an angle to each other and are rotatably mounted in the housing (11), characterized byin that either the first bevel gear (20) is provided with a flank modification (FM) on all right-hand or all left-hand tooth flanks (23), or in that the second bevel gear (30) is provided with a flank modification (FM) on all right-hand or all left-hand tooth flanks (33), wherein the flank modification (FM) prevents a collision of the tooth flanks (23, 33) during assembly of the two bevel gears (20, 30) in the housing (11) or during disassembly of the two bevel gears (20, 30) from the housing (11), wherein the flank modification (FM) is produced by CNC-controlled post-machining using second machine data (MD2) from the method for enabling or improving the drawability of the first and second bevel gears (20, 30) according to claim 1. [10] Bevel gear (10) according to claim 9, characterized bythat the second bevel gear (30) is a ring gear and that the flank modification (FM) is located on all right or all left tooth flanks (33) of the ring gear. [11] Bevel gear (10) according to claim 9 or 10, characterized by that the flank modification (FM) is located in a region near the heel of one of the two bevel gears (20, 30).

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