TOOL FOR PRODUCEING RECORDS ON THE TEETH OF A GEAR-SHAPED WORKPIECE AND METHOD FOR SIMULTANEOUSLY PRODUCE AT LEAST TWO RECORDS ON THE TEETH OF THE WORKPIECE

Description

[0001] The invention relates to a tool for producing deposits on teeth of a gearing of a gear-shaped workpiece, wherein the tool comprises a tool holder which is elongated in the manner of a pin and aligned coaxially with the central longitudinal axis of the tool and at least two cutting edges which, during use, come into cutting engagement with the tooth to be machined, wherein the cutting edges are held on the tool holder at a distance from one another in the longitudinal direction of the tool holder and each extend over a partial length of the tool holder.

[0002] The invention also relates to a method for simultaneously producing at least two deposits on each of the teeth of a gearing of a gear-shaped workpiece by means of a tool of the type explained above.

[0003] Typically, the gears to be machined with a tool according to the invention or by applying a method according to the invention are so-called "sliding sleeves." These are required in manual transmissions of vehicles powered by an internal combustion engine. To ensure that the gear-shaped workpiece, which is brought into engagement with the sliding sleeve for power transmission, remains in engagement with the sliding sleeve even under the high loads encountered during use, so-called "backings" are usually formed on the tooth flanks of at least some of the teeth of the sliding sleeve. These shaped elements, designed as recesses or shoulders with a precisely defined geometry, prevent unwanted axial displacement of the gear-shaped workpiece meshing with the sliding sleeve.The backings are typically formed into the end regions of the tooth flanks of the teeth of the gearing adjacent to the respective end face of the gear-shaped workpiece.

[0004] A tool according to the preamble of claim 1 and a method according to the preamble of claim 5 of the type specified at the outset are known, for example, from DE 101 27 973 A1. The use of a tool comprising two cutting edges described therein allows two backings to be created on a gear wheel simultaneously. For this purpose, in the prior art, the cutting edges are arranged in a line that is aligned axially parallel to the central longitudinal axis of the tool, which coincides with its axis of rotation. The width of the cutting edges, measured in the longitudinal direction of the tool carrier, corresponds to the width of the backing they are to cut into the respective tooth flank, and the distance between the cutting edges corresponds to the distance that is to exist between the backings to be formed on the respective tooth flank. At the same time, the cutting edges can also be designed to match the shape of the backings to be formed.If, for example, deposits are to be produced whose depth increases from the edge of the deposit assigned to the respective end face of the gear in the direction of the width center of the tooth flank provided with the deposits, this can be achieved by cutting edges whose thickness increases in a corresponding manner from their narrow side assigned to the respective end face of the gear in the direction of the opposite narrow side, so that the cutting edge has a cutting edge which runs obliquely in a plan view of the cutting edge.

[0005] To ensure proper function of a gear-shaped workpiece with backing, the shape, position, and alignment of the backing must precisely match the specifications resulting from the gear's design. Compliance with this specification proves difficult when the loads encountered during use are so great that the tool itself or the tool holder in which the tool is clamped deforms. Such deformations occur particularly when the tool holder is very long, leading to high bending or torsional loads as a result of the transverse forces occurring during machining of the teeth of the gear-shaped component.

[0006] Tools with tool holders that are longer and therefore have an increased overhang relative to the clamping device in which they are held are required, for example, for machining the tooth flanks of teeth on sliding sleeves or similar gears that are of a similar width. Such wide gears are required, for example, in the gearboxes of heavy machinery in order to be able to absorb the loads that occur during their use. In order to be able to create two backings on selected teeth at the same time on such wide gears, a tool must be used whose tool holder has a length that corresponds to the width of the gear-shaped workpiece. In particular, the resulting slim, elongated shape of the tool holder brings with it the risk that the tool holder or the tool holder holding the tool will deform during machining.This deformation can consist of a bending transverse to its central longitudinal axis or a twisting of the tool around its central longitudinal axis, whereby these types of deformation can also overlap.

[0007] DE 10 2005 025 000 A1 is also known from the state of the art; this discloses a tool with fine adjustment.

[0008] Against the background of the state of the art explained above, the task arose to create a tool that enables the high-precision, simultaneous production of two deposits on the tooth flanks of the teeth of a gear-shaped workpiece, regardless of their width.

[0009] A process should also be mentioned that allows two deposits to be produced simultaneously and with high precision on the tooth flanks of teeth of a gear-shaped workpiece, even with a tool that has a delicately shaped, elongated tool carrier.

[0010] The invention has solved this problem by the tool specified in claim 1 and the method specified in claim 5.

[0011] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below, as is the general inventive concept.

[0012] A tool according to the invention for producing deposits on teeth of a gearing of a gear-shaped workpiece therefore comprises, in accordance with the prior art set out at the outset, a tool carrier which is elongated in the manner of a pin and aligned coaxially with the central longitudinal axis of the tool, and at least two cutting edges which, during use, come into machining engagement with the tooth of the gear-shaped workpiece to be machined, wherein the cutting edges are held on the tool carrier at a distance from one another in the longitudinal direction of the tool carrier, and their width each extends over a partial length of the tool carrier.

[0013] According to the invention, in such a tool, the position of at least one of the cutting edges is adjustable in relation to the other cutting edge to compensate for deformations of the tool carrier that occur during use.

[0014] In a corresponding manner, in a method according to the invention, at least two deposits are produced simultaneously on the teeth of a toothing of a gear-shaped workpiece by means of a tool rotating about its central longitudinal axis, wherein the tool comprises a tool holder which is elongated in the manner of a pin and aligned coaxially with the central longitudinal axis of the tool and at least two cutting edges which, during use, come into machining engagement with the tooth to be machined, wherein the cutting edges are held on the tool holder at a distance from one another in the longitudinal direction of the tool holder and each extend over a partial length of the tool holder.

[0015] According to the invention, a tool according to the invention is used for such a method and, based on this, at least the following work steps are carried out: a) Determining the bending and / or torsional deformation experienced by the tool holder or the clamping device in which the tool is held during the creation of the backings; b) Adjusting the position of an adjustable cutting edge of the tool in relation to the other cutting edge of the tool, taking into account the deformation determined in step a), such that the position and shape of the backings to be created on the teeth of the gear type each meet a target specification; c) Creating the backings on the teeth of the gear-shaped workpiece.

[0016] The invention thus provides a backing tool that enables the simultaneous creation of two backings on the teeth of a gear-shaped workpiece, typically a sliding sleeve for a manual transmission. The tool according to the invention allows the creation of backings that meet even the most stringent requirements regarding their geometry, position, and alignment, even for particularly wide teeth that require an elongated, slender tool carrier. This particularly applies to the angular positions of the backings, for which optimal compliance with the respective target specifications can be ensured using a tool according to the invention.

[0017] The invention is based on the finding that, for an exact reproduction of two deposits on a tooth flank of a gear tooth, it is not necessary to stiffen the tool carrier or the tool holder so that they do not deform under the loads occurring during use. Rather, according to the findings of the invention, it is sufficient to align at least one of the cutting edges on the tool carrier of a tool according to the invention with respect to the other cutting edge in such a way that geometric errors are compensated for, which would inevitably occur without suitable countermeasures as a result of the deformation of the tool or the tool holder accepted according to the invention.

[0018] In order to enable such an alignment with the greatest possible variability and, consequently, to make a tool according to the invention suitable for machining different types of gear-shaped workpieces, in particular sliding sleeves, and for use in different machines with different workpiece holders, the position of at least one of the cutting edges in a tool according to the invention can be changed with respect to the other.

[0019] Typically, in a tool according to the invention, the first cutting edge is fastened in a region arranged at the free end of the tool carrier, while the second cutting edge is arranged in the end region associated with the opposite end of the tool carrier, which is usually connected to a clamping pin used to clamp the tool in a tool holder. A circumferential shoulder can be provided between the clamping pin and the tool carrier, which forms the transition between the tool carrier and the clamping pin. The circumferential shoulder can be designed like a collar protruding radially from the pin and forming a stop up to which the clamping pin can be inserted into the tool holder.

[0020] In a tool according to the invention, the greatest deformations occur in the area of ​​the free end of the tool due to its slender shape. Therefore, at least the position of the cutting edge provided there is preferably adjustable in the manner according to the invention in order to compensate for the shape errors of the backings to be produced that would otherwise be caused by the deformation of the tool carrier or the tool holder. In contrast, the other cutting edge, which is arranged near the tool clamping point during use, can generally be fixedly mounted, since in practice only negligible deformations of the tool carrier occur in the area closely adjacent to the clamping point. In this embodiment, the cutting edge, which is fixed and invariably mounted near the clamping pin on the tool carrier provided for clamping, then forms a fixed reference for the adjustment of the variably positionable cutting edge.This makes adjusting the position of the adjustable cutting edge particularly easy. However, in cases where the significant portion of the deformation takes place in the tool holder, it may also be expedient to make each of the cutting edges of a tool according to the invention adjustable. This also makes it possible to compensate for the complex shape errors of the deposits to be produced, which would be caused by the deformation of the tool holder and the resulting deviation of the tool from its desired position.

[0021] Depending on the deformations of the tool holder occurring during use, it may be expedient to provide an adjustability of the adjustable cutting edge in the radial direction relative to the central longitudinal axis of the tool (to compensate for a bending of the tool holder or the tool holder) or, according to patent claim 1, an adjustability of the adjustable cutting edge in the circumferential direction of the tool holder (to compensate for a twisting of the tool holder), whereby these two possibilities for adjusting the position of the respectively adjustable cutting edge can also be combined with one another.

[0022] The deformation of the tool or tool holder occurring during use as a result of bending and / or torsional deformation and the associated deviation of the position of the cutting edges, in particular of the adjustable cutting edge, from the target position, which results during use due to the loads occurring during use, can be determined in step a) of the method according to the invention by practical tests or computationally, for example by a computer-aided simulation, in a manner known per se.

[0023] The adjustment of the position of at least one adjustable cutting edge of the tool in relation to the other cutting edge of the tool is then carried out in step b) taking into account the deformation determined in step a) in such a way that the position and shape of the deposit to be created on the teeth of the gear type each meet a target specification.

[0024] For adjustment, the respective adjustable cutting edge can be held on a carrier which can be positioned in different positions on the tool carrier, for example by means of a detachable, force-locking and / or form-locking connection, such as a screw or clamp connection.

[0025] With a correspondingly adjusted tool according to the invention, the position of at least one of the cutting edges deviates from the target position when unused and unloaded. However, this target position automatically adjusts during machining of the gear-shaped workpiece (work step c)) in use due to the deformations of the tool or tool holder that occur during this process. As a result, optimal work results are achieved during the subsequent machining of the gears without the need for further measures.Thus, the tool according to the invention and the method according to the invention are particularly suitable for series machining of gear-shaped workpieces, since the adjustment of the position of the respectively adjustable cutting edge carried out in work step b) on the basis of the determination of the deformation of the workpiece or workpiece holder once carried out in work step a) applies to all similarly designed workpieces in a series (work step c)).

[0026] According to a practical embodiment of the invention, the distance between the cutting edges measured in the longitudinal direction of the tool carrier, ie axially parallel to the central longitudinal axis of the tool, is at least four times the length of the cutting edges, with distances between the cutting edges corresponding to at most fifteen times the width of the cutting edges covering the machining tasks commonly occurring in practice.

[0027] The width B of the cutting edges, measured in the longitudinal direction, typically amounts to at most 20% of the length of the tool holder, with the cutting edges typically having a width of at least 5 mm in practice. Thus, the tool holder of a tool according to the invention typically has a length of at least 25 mm, in particular at least 30 mm, with lengths of up to 200 mm covering the machining tasks encountered in practice. The diameters of the tool holders of tools according to the invention are typically up to 50 mm, so that the ratio Lwt / Dwt formed from the length Lwt and the diameter Dwt is typically 0.5 - 4.

[0028] The invention is explained in more detail below with reference to an exemplary embodiment. The drawings are schematic and not to scale: Fig. 1 shows a tool for producing deposits on the teeth of a sliding sleeve in a perspective view; Fig. 2 shows the tool according to Fig. 1 in a frontal view; Fig. 3 the tool according to Fig. 1 in a top view.

[0029] The tool 1 for producing deposits comprises a pin-like, elongated tool carrier 2, which has a cylindrical basic shape and is aligned coaxially with the central longitudinal axis L of the tool 1. The central longitudinal axis L of the tool 1 coincides with the axis of rotation around which the tool 1 rotates in use.

[0030] The tool carrier 2 is carried by a clamping pin 3, which serves to clamp the tool 1 in a tool holder (not shown here) of a conventionally designed machine tool (also not shown). The diameter Dz of the clamping pin 3 is greater than the diameter Dwt of the tool carrier 2, while the length Lwt of the tool carrier 2, measured axially parallel to the longitudinal axis L, is approximately 3.5 times greater than the length Lz of the clamping pin 3, also measured axially parallel to the longitudinal axis L. The transition between the tool carrier 2 and the clamping pin 3 is formed by a shoulder 4 designed like a circumferential collar, the diameter of which is greater than the diameter Dz of the clamping pin 3, so that the shoulder 4 projects radially outwards beyond the clamping pin 3 and forms a stop up to which the clamping pin 3 can be pushed into the tool holder (not shown) for use.

[0031] Two cutting edges 5, 6 are attached to the tool carrier 2. During use, these cutting edges simultaneously create two deposits on a tooth flank of the respective machined tooth of a sliding sleeve (not shown here) by removing material from the tooth. In the example shown here, the deposits are mirror-symmetrical relative to the center of the width of the tooth surface. However, they can also be arranged or designed asymmetrically.

[0032] For this purpose, a recess 7 is provided in an end region of the tool carrier 2 adjacent to the shoulder 4 and assigned to the clamping pin 3, in which recess a carrier element 8 is precisely seated. This carrier element 8 has a curved outer surface that fits into the outer contour of the cylindrical tool carrier 2. The carrier element 8 is fixed to the tool carrier 2 by means of screws 9, 10. At one of its edges, which is aligned parallel to the longitudinal axis L, the cutting edge 5 is seated in a cutout 11 of the carrier element 8 and is fixed there by the carrier element 8 in its position and angular position β with respect to the longitudinal axis L of the tool carrier 2.

[0033] For fastening the second cutting edge 6, a further recess 13 is provided in an end region adjacent to the free end face 12 of the tool carrier 2, in which recess a carrier element 14 sits precisely. The carrier element 14 is shaped corresponding to the carrier element 8 such that its outer surface fits into the outer contour of the tool carrier 2 and is fixed to the tool carrier 2 by means of a screw. The cutting edge 6 is held by an insert piece 15 which sits in a recess 16 of the carrier element 14. The recess 16 extends in the circumferential direction U of the tool carrier 2 and is supplemented by a recess 17 which is formed in the tool carrier 2. By moving the insert piece 15 in the circumferential direction U within the recesses 16, 17, the angular position ß' of the cutting edge 6 with respect to the central longitudinal axis L and thus with respect to the angular position β of the fixed first cutting edge 5 can be adjusted.

[0034] In addition, the insert 15, with the cutting edge 6 carried by it and adjustable in position, can be adjusted in the radial direction R relative to the central longitudinal axis L. The fixation of the insert 15 and the cutting edge 6 in the respective angular position ß' and the respective radial position on the tool carrier 2 is again effected by a screw 18.

[0035] The cutting edges 5, 6 are each aligned in the longitudinal direction LR of the tool carrier 3 and mirror-symmetrically to each other. The cutting edges 5, 6 have a smaller thickness on their narrow sides facing away from each other than on their narrow sides facing each other, so that the cutting edges 5a, 6a of the cutting edges 5, 6 are aligned obliquely with respect to the orientation of the central longitudinal axis L.

[0036] The distance A between the mutually associated wider narrow sides of the cutting edges 5,6 corresponds approximately to six times the width B of the cutting edges 5,6 measured axially parallel to the longitudinal axis L, the width B of which in turn corresponds approximately 10% of the length Lwt of the tool carrier 3.

[0037] In the nominal position, the center lines MS of the cutting edges 5, 6 are aligned on a line ML that is axially parallel to the central longitudinal axis L. In this alignment, optimally uniform backings are obtained on the tooth flank of the respective tooth to be machined.

[0038] During use, the transverse forces and moments that occur during the machining of the teeth of the gearing to be machined may cause the tool carrier 2 to deform due to torsion ( Fig. 2 ) or bend ( Fig. 3 ) come.

[0039] In the case of torsion, the tool carrier 2 rotates more strongly towards its front free end face 12 against the direction of rotation DR than in its end region associated with the clamping pin 3. Consequently, without countermeasures, the angular position ß' of the cutting edge 6 associated with the free end face 12 with respect to the central longitudinal axis L would deviate from the angular position β = 0° of the non-adjustable cutting edge 5 associated with the clamping pin 3, which is also related to the central longitudinal axis L, against the direction of rotation DR by an angular amount Δß. The resulting position of the cutting edge 6 is shown in Fig. 2 indicated by dashed lines.

[0040] To compensate for this change in the position of the adjustable cutting edge 6 compared to the target position caused by the torsional deformation of the tool holder 2, the insert piece 15 with the cutting edge 6 is displaced in the direction of rotation DR by the angular amount Δß in the circumferential direction U. When not in use and unloaded, the position of the cutting edge 6 therefore deviates from the target position. During use, however, due to the then occurring torsional deformation of the tool holder 2, the cutting edge 6 is in its target position, in which it is aligned in line with the fixed cutting edge 5. In the case of small deviations, the change in position of the cutting edge 6 caused by the torsional deformation, which basically follows a circular arc, can be approximated by a linear adjustment transverse to the longitudinal axis L of the tool.If it turns out that, despite the adjustment carried out in this way, the change in position of the cutting edge 6 caused by the torsion cannot be compensated, the cutting edge 6 can be repositioned to follow the arc shape to compensate.

[0041] In the case of bending, either the tool carrier 2 itself is bent towards the free end face 12 or the tool holder (not shown here) is deformed in such a way that the longitudinal alignment of the longitudinal axis of the tool carrier 2 deviates from the desired position of the central longitudinal axis L. The resulting deformation is in Fig. 3 illustrated by dashed lines. Consequently, without countermeasures, the radial position r' of the cutting edge 6 with respect to the longitudinal axis L would deviate by a distance Δr from its radial target position r.

[0042] To compensate for this deviation, the insert piece 15 with the cutting edge 6 is displaced outwards by the amount Δr in the radial direction R relative to the central longitudinal axis L, so that when the tool 1 is not in use, the position of the adjustable cutting edge 6 deviates from its target position, but the cutting edge 6 is in the target position during use, ie during machining of the teeth of the sliding sleeve, due to the change in its position caused by the resulting bending deformation. REFERENCE SYMBOL

[0043] 1Tool for creating backings 2Tool holder of tool 1 3Clamping pin of tool 1 4Circumferential shoulder of tool 1 5Fixed, non-adjustable cutting edge of tool 1 5a, 6aCutting edges of cutting edges 5, 6 6Variably adjustable cutting edge of tool 1 7Recess of tool holder 2 8Carrier element 9, 10Screws for fastening the carrier element 8 11Cutout of the carrier element 8 12Free end face of tool holder 2 13Recess of tool holder 2 14Carrier element 15Insert supporting cutting edge 6 16Recess of carrier element 14 17Recess of tool holder 2 18Screw for fixing insert 15 ßAngular position of the cutting edge 5 in relation to the longitudinal axis L ß'Angular position of the cutting edge 6 in relation to the longitudinal axis L ΔßAngular amount ΔrDistance AAspacing between the cutting edges 5.6 BWidth of the cutting edges 5.6 DRDirection of rotation of the tool 1 DwtDiameter of the tool holder DzDiameter of the clamping pin 3 LCentral longitudinal axis of the tool 1 LRLongitudinal direction LwtLength of the tool holder 2 LzLength of the clamping pin 3 MSCenter lines of the cutting edges 5.6 MLaxle parallel to the central longitudinal axis L UCircumferential direction of the tool holder 2 Rradial direction R

Claims

1. Tool for producing undercuts on teeth of a toothing of a gear-shaped workpiece, the tool (1) comprising a tool carrier (2) which is designed elongated like a pin and is aligned coaxially with the central longitudinal axis (L) of the tool (1) and at least two cutting edges (5, 6) which, in use, come into chip-removing engagement with the respective tooth of the gear-shaped workpiece to be machined, the cutting edges (5,6) are held on the tool carrier (2) at a distance from one another in the longitudinal direction (LR) of the tool carrier (2) and their width (B) extends in each case over a partial length of the tool carrier (2), characterized in that the position of at least one of the cutting edges (6) is adjustable in relation to the other cutting edge (5) in order to compensate for deformations of the tool carrier (2) which occur during use, and that the position of the adjustable cutting edge (6) is adjustable in the circumferential direction (U) of the tool carrier (2).

2. Tool according to claim 1, characterized in that the position of the adjustable cutting edge (6) is adjustable in a radial direction (R) relative to the central longitudinal axis (L).

3. Tool according to one of the preceding claims, characterized in that the distance (A) between the cutting edges (5, 6) measured in the longitudinal direction (LR) of the tool carrier (2) corresponds to at least four times the width (B) of the cutting edges measured in the longitudinal direction (LR) of the tool carrier (2).

4. Tool according to one of the preceding claims, characterized in that the width (B) of the cutting edges (5, 6) measured in the longitudinal direction (LR) of the tool carrier (2) is at most 20% of the length (Lwt) of the tool carrier (2).

5. Method for simultaneously producing at least two undercuts on the teeth of a toothing of a gear-shaped workpiece by means of a tool (1) rotating about its central longitudinal axis (L), wherein the tool (1) comprises a tool carrier (2), which is which is designed elongated like a pin and is aligned coaxially to the central longitudinal axis (L) of the tool (1), and at least two cutting edges (5, 6), which in use come into chip-removing engagement with the respective tooth to be machined, wherein the cutting edges (5,6) are held on the tool carrier (2) at a distance from one another in the longitudinal direction of the tool carrier (2) and each extend over a partial length of the tool carrier (2), characterized in that with the tool (1) used, the position of at least one of the cutting edges (6) can be adjusted in relation to the other cutting edge (5) to compensate for deformations of the tool carrier (2) which occur during use and that at least the following steps are carried out to produce the undercuts: a) Determining the bending and / or torsional deformation which the tool carrier (2) or the clamping in which the tool (1) is held undergoes when the undercuts are produced; b) Setting the position of an adjustable cutting edge (6) of the tool (1) in relation to the respective other cutting edge (5) of the tool (1), taking into account the deformation determined in step a), in such a way that the position and shape of the undercuts to be produced on the teeth of the gear type each fulfill a target specification; c) Creating the undercuts on the teeth of the gear-shaped workpiece.

6. Method according to claim 5, characterized in that the gear-shaped workpiece is a sliding sleeve for a gearbox.