DE102011088864A1 - Method for manufacturing material-deforming tool i.e. calibrating press, for manufacturing and calibrating mono block ratchet wheels, involves processing embossing surfaces by high speed cutting milling process for calibrating teeth - Google Patents

Abstract

The method involves installing mono block ratchet wheels with clutch teeth (20). Embossing surfaces of a material-deforming tool i.e. calibrating press, are processed by high speed cutting milling process for calibrating the coupling teeth. The embossing surfaces include negative teeth for the clutch teeth with a tooth head radius of less than 0.35 mm preferably 0.25 mm. Large rounding milling heads are smoothened, and forming tool segments have the embossing surfaces for converting the clutch teeth of the mono block ratchet wheels. An independent claimS are also included for the following: (1) a material-deforming tool for manufacturing of mono block ratchet wheels with clutch teeth (2) a mono block ratchet wheel.

Description

Technical area

The present invention relates to a method for producing a forming tool, in particular a Kaltkalibrierpresse, Monoblockschalträder with ready-to-install clutch teeth, such a forming tool, in particular such Kaltkalibrierpresse, and a monoblock gear wheel thus produced.

State of the art

For the production of gears a variety of methods is known. Here, a distinction is made between non-cutting and machining processes. The present application focuses on chipless manufacturing processes in which a calibration, which is a fine forging process, is performed in one manufacturing step. Such a forming production has cost advantages over a machining production. Furthermore, process steps and process tools for machining can be omitted, thereby shortening the process chain is made possible.

In manual and double clutch transmissions for passenger cars, the gear wheels are provided with coupling teeth, which have an undercut. The engagement behavior during the gear change is largely determined by the tooth shape and the dimensional tolerance of the coupling teeth. For this reason, in the case of using a non-cutting method, a final finishing step in the form of calibration is common.

The EP 0 189 447 B1 describes a method for producing a short-toothed synchronous component with undercut teeth for manual transmission by Genauschmieden, the teeth, which are each attached with its radially inner side to a common cylindrical surface and placed with her foot on a common lower face, initially with parallel running tooth flanks produced and then compressed. First, a semi-finished product is produced by pre-forging, the short teeth of which have teeth with an oversize which exceeds the finished tooth head. Thereafter, the semifinished product is acted upon by one or more calibration strokes so that the tooth tips receive a roof shape and the tooth flanks receive an oblique position corresponding to their undercut.

Another forging process for the production of synchronous parts for manual transmission is in the DE 31 34 857 A1 described. Therein, the forging is first forged and then subjected to a cold calibration.

For calibration, which is a forming operation to produce the final geometry, a cold-sizing press may be used. In the case of the production of Monoblockschalträdern with ready-to-install clutch teeth, the sizing has a toothed die for forming the coupling teeth, which corresponds to the trainees coupling teeth as a negative. Usually the calibration is preceded by a soft machining of the workpiece.

High demands are placed on the calibration tool for precision forging. In addition to the force-locking closing of the upper and lower tool, or depending on the design of the tool segments, the precision and the surface finish of the functional surfaces have a direct effect on the final shape of the product to be forged. The negative toothing in the sizing press is engraved by erosion in the tool segments in the prior art. The erosion causes a rounding of edges of the coupling teeth on the forged ratchet with tooth head radii of more than 0.35 mm.

Description of the invention

An object of the invention is to provide a method for producing a forming tool, in particular a sizing press, and a forming tool, in particular a sizing press, with which monoblock scarf wheels with ready-to-install coupling teeth with improved engagement characteristics can be produced.

The object is achieved by a method according to claim 1, a forming tool according to claim 5 and a Monoblockschaltrad according to claim 9.

The method for producing the forming tool according to the invention, in particular the sizing press, is characterized in that the engraving of the stamping surfaces takes place at least partially by means of HSC milling (high-speed cutting). By means of the HSC technology, an excellent surface quality of the surfaces forming the toothing is achieved. The improved accuracy allows the production of complex three-dimensional contours with finer rounding of edges. Thus, tooth head radii on the coupling teeth of the monoblock gears can be less than 0.35 mm, even less than about 0.25 mm. The HSC milling precision tool can be easily and flexibly made on the basis of CAD data. Due to the surface quality and the more precise Representation of the edges, in particular the head radii, the Einkuppelverhalten the Monoblockschalträder is improved. Furthermore, less wear occurs due to the smaller dimensional tolerance.

Preferably, to further improve the manufacturing accuracy, the stamping surfaces are produced exclusively by HSC milling.

The tool produced according to the invention is preferably a press and preferably designed for cold calibration, i. H. for forging cold steel, which can be heated up to a maximum temperature of about 150 ° C by the energy of the forming process. By cold forging particularly tight dimensional tolerances can be achieved.

As a forming tool are a hydraulic press, a mechanically acting press, a hammer, a hybrid tool, d. H. on the one hand hydraulically and on the other hand mechanically acting tool suitable. The forming can be done as cold forming, warm forging or as Lauwarmumformen, with this forming process certain temperature ranges are connected. In cold forming, forming takes place well below the recrystallization temperature. In warm forging, a temperature below the Curie temperature, in particular a temperature range of between 700 ° C and 900 ° C, used and in Lauwarmumformen the forming takes place in the temperature range of between 600 ° C and 700 ° C.

Brief description of the figures

1A to 1D show different Monoblockschalträder;

2 shows an enlarged detail of the coupling teeth of a Monoblockschaltrades;

3 shows the 3D contour of the negative toothing in a sizing press.

Ways to carry out the invention

1A to 1D show embodiments of Monoblockschalträdern with ready to install clutch teeth. 1A shows a gear wheel with a 3-cone synchronization with the corresponding recesses 10 for fixing the synchronizer ring, which is not shown. The teeth of the undercut coupling teeth are with the reference sign 20 designated. An alternative ratchet wheel is in the 1B shown, which is also designed for a 3-cone synchronization. A Monoblockschaltrad for a 1-Konus synchronization is in the 1C shown. In the 1A and 1C are also oil grooves 11 in the shaft 2 introduced, to improve the lubricant supply. A ratchet wheel for a 2-cone synchronization with breaks 12 the coupling teeth is in the 1D shown.

To produce such Monoblockschalträder a blank is first separated from a solid round rod made of steel. The blank is heated and forged for hot forging, the coupling teeth being made coarse. Subsequently, the preformed intermediate product is removed from the forging press and fed to a Kaltkalibrierpresse. Between the hot forging and the cold calibration, further process steps may be provided, such as a deburring process. The intermediate product is inserted into the sizing press and cold-formed by a force-locking closing of the tool segments.

In 3 the contour of the toothing is shown in the calibration tool. Here, the reference sign denotes 20 ' the negative contour for a tooth 20 , It should be noted that the names of the negative features of the 3 , which correspond to the characteristics of the monoblock gear, are provided with a "'".

In the 2 is an enlarged section of the coupling teeth shown from the shape of the teeth 20 after calibration. As it is in 2 is shown has a tooth 20 for the toothing tooth flanks 21 on, possibly from a lower plane 22 extend. To the tooth flanks 21 the tooth head closes 23 at.

The work hardening allows the formation of dimensionally accurate, the coupling surfaces forming tooth flanks with a desired inclination and broadening the tooth head 23 out.

The tooth tip radius at the point R of less than 0.35 mm, preferably 0.25 mm, allows an improved engagement of the gear wheel.

To achieve such tooth head radii, the negative toothing is introduced by means of HSC milling into the embossing segments of the sizing press.

For example, a high precision and dynamic 5-axis HSC milling machine of the DMC105V type from Deckel Maho Gildermeister is used. This is a milling machine with a high-speed spindle with speeds of up to 60,000 rpm. The 5-axis CAM system offers the possibility to program smallest tools in a stress-optimized way. This is a milling head with a smallest diameter of 0.2 mm, which can handle a material hardness of up to 58 HRC. The milling machine offers the possibility of highly precise measuring of tooth contours with an undercut, the resulting measured values being used for the milling strategy outlined below.

In the following description of the milling strategy, the methods "roughing", "pre-finishing" and "finishing" are used. These are to be characterized as follows:
When roughing most of the material to be removed is milled and an allowance to the finished contour between 0.03 mm to 0.2 mm maintained. On the other hand, during pre-finishing, a uniform allowance of 0.015 mm to 0.03 mm is milled to the finished contour. During finishing, the finished contour is finally produced with the required surface quality and accuracy.

First, the tool to be processed in the sizing press is roughed in four steps with different sized milling heads, namely with a D16 / R4 milling head (figures in mm), then a D8 / R4 milling head and then a D6 / R3 milling head and then with a D2 / R1 Milling head roughed and pre-painted. Then the teeth of the tool are preassembled with a D2 / R1 milling head and then a D1 / R0.5 milling head. In the case of the milling heads mentioned, D denotes the diameter of the milling head with respect to the axis of rotation of the milling head, and R denotes the radius of curvature of the milling head in the axial direction.

Pre-finishing is further applied to the teeth and teeth plane with the D1 / R0.5 milling head.

This is followed by two finishing programs, initially with a D0.6 / R0.3 milling head for the teeth and the tooth plane as well as the tooth roof. Then a sizing of a pitch with a D2 / R1 and then a D1 / R0.5 cutter is inserted.

Finally, a final sizing with a D0,4 / R0,2 milling head takes place on the teeth.

• 1. Schruppbearbeitung aller Bereiche des Werkzeugrohlings mit Aufmaß, Messerkopf mit Wendeplatten: Durchmesser 16 mm, Eckenradius 4 mm, Aufmaß 0,18 mm;
• 2. Schruppbearbeitung aller Bereiche mit Aufmaß, Vollhartmetallkugelfräser: Durchmesser 8 mm, Eckenradius 4 mm, Aufmaß 0,1 mm;
• 3. Schruppbearbeitung aller Bereiche mit Aufmaß, Vollhartmetallkugelfräser: Durchmesser 6 mm, Eckenradius 3 mm, Aufmaß 0,1 mm;
• 4. Schruppbearbeitung aller Bereiche mit Aufmaß, Vollhartmetallkugelfräser: Durchmesser 2 mm, Eckenradius 1 mm, Aufmaß 0,03 mm;
• 5. Vorschlichten der flachen Bereiche der Kupplungsverzahnung, Vollhartmetallkugelfräser: Durchmesser 2 mm, Eckenradius 1 mm, Aufmaß 0,02 mm;
• 6. Schruppen der Kupplungsverzahnung, Vollhartmetallkugelfräser: Durchmesser 1 mm, Eckenradius 0,5 mm, Aufmaß 0,03 mm;
• 7. Vorschlichten der steilen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt, Vollhartmetallkugelfräser: Durchmesser 1 mm, Eckenradius 0,5 mm, Aufmaß 0,015 mm;
• 8. Vorschlichten der flachen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt, Vollhartmetallkugelfräser: Durchmesser 1 mm, Eckenradius 0,5 mm, Aufmaß 0,015 mm;
• 9. Schlichten der steilen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt, Vollhartmetallkugelfräser: Durchmesser 0,6 mm, Eckenradius 0,3 mm, Aufmaß 0,000 mm;
• 10. Schlichten der flachen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt, Vollhartmetallkugelfräser: Durchmesser 0,6 mm, Eckenradius 0,3 mm, Aufmaß 0,000 mm;
• 11. Schlichten des Zahndachs, Vollhartmetallkugelfräser: Durchmesser 0,6 mm, Eckenradius 0,3 mm, Aufmaß 0,000 mm;
• 12. Schlichten der oberen Kontur (Teilung) Vollhartmetallkugelfräser: Durchmesser 2 mm, Eckenradius 1 mm, Aufmaß 0,000 mm;
• 13. Schlichten Restmaterial der oberen Kontur (Teilung), Vollhartmetallkugelfräser: Durchmesser 1 mm, Eckenradius 0,5 mm, Aufmaß 0,000 mm;
• 14. Schlichten der steilen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt 1. Teilbereich, Vollhartmetallkugelfräser: Durchmesser 0,4 mm, Eckenradius 0,2 mm, Aufmaß 0,000 mm;
• 15. Schlichten der steilen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt 2. Teilbereich, Vollhartmetallkugelfräser: Durchmesser 0,4 mm, Eckenradius 0,2 mm, Aufmaß 0,000 mm;
• 16. Schlichten der steilen Bereiche der Kupplungsverzahnung mit dem Hinterschnitt 3. Teilbereich, Vollhartmetallkugelfräser: Durchmesser 0,4 mm, Eckenradius 0,2 mm, Aufmaß 0,000 mm.

In detail, the manufacturing strategy is:

• 1. Roughing of all areas of the tool blank with allowance, cutter head with inserts: diameter 16 mm, corner radius 4 mm, allowance 0.18 mm;
• 2. Roughing of all areas with allowance, solid carbide ball end mill: diameter 8 mm, corner radius 4 mm, allowance 0.1 mm;
• 3. Roughing of all areas with allowance, solid carbide ball end mill: diameter 6 mm, corner radius 3 mm, allowance 0.1 mm;
• 4. Roughing of all areas with allowance, solid carbide ball end mill: diameter 2 mm, corner radius 1 mm, allowance 0.03 mm;
• 5. Semi-finishing of the flat areas of the coupling teeth, solid carbide ball end mill: diameter 2 mm, corner radius 1 mm, allowance 0.02 mm;
• 6. Roughing of the coupling teeth, solid carbide ball end mill: diameter 1 mm, corner radius 0.5 mm, allowance 0.03 mm;
• 7. Pre-finishing of the steep areas of the coupling teeth with the undercut, solid carbide ball end mill: diameter 1 mm, corner radius 0.5 mm, allowance 0.015 mm;
• 8. Semi-finishing of the flat areas of the coupling teeth with the undercut, solid carbide ball end mill: diameter 1 mm, corner radius 0.5 mm, allowance 0.015 mm;
• 9. Finishing of the steep areas of the coupling teeth with the undercut, solid carbide ball end mill: diameter 0.6 mm, corner radius 0.3 mm, allowance 0.000 mm;
• 10. Finishing the flat areas of the coupling teeth with the undercut, solid carbide ball end mill: diameter 0.6 mm, corner radius 0.3 mm, allowance 0.000 mm;
• 11. Finishing of the tooth roof, solid carbide ball end mill: diameter 0.6 mm, corner radius 0.3 mm, allowance 0.000 mm;
• 12. Finishing the upper contour (pitch) Solid carbide ball end mill: diameter 2 mm, corner radius 1 mm, allowance 0.000 mm;
• 13. Finishing residual material of the upper contour (pitch), solid carbide ball end mill: diameter 1 mm, corner radius 0.5 mm, allowance 0.000 mm;
• 14. Finishing of the steep areas of the coupling toothing with the undercut 1st partial area, solid carbide ball end mill: diameter 0.4 mm, corner radius 0.2 mm, allowance 0.000 mm;
• 15. Finishing of the steep areas of the coupling toothing with the undercut 2nd partial area, solid carbide ball end mill: diameter 0.4 mm, corner radius 0.2 mm, allowance 0.000 mm;
• 16. Finishing the steep areas of the coupling teeth with the undercut 3. Sub-area, solid carbide ball end mill: diameter 0.4 mm, corner radius 0.2 mm, allowance 0.000 mm.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0189447 B1 [0004]
• DE 3134857 A1 [0005]

Claims (11)

Method for producing a forming tool, in particular a sizing press, for producing, in particular calibrating, monoblock scrapers with ready-to-install coupling teeth, in which the stamping surfaces of the tool for calibrating the coupling teeth are machined by means of HSC milling. A method according to claim 1, characterized in that the stamping surfaces are produced exclusively by HSC milling. A method according to claim 1 or 2, characterized in that the embossing surfaces negative teeth ( 20 ' ) for the coupling teeth with a tooth tip radius (R ') of less than 0.35 mm. A method according to claim 3, characterized in that the tooth tip radius (R ') is 0.25 mm or less. Method according to one of the preceding claims, characterized in that with different sized Abrundfräsköpfen initially scrubbed, then pre-classified and then sized. Forming tool for producing Monoblockschalträdern with ready-to-install clutch teeth, wherein the forming tool has tool segments with stamping surfaces for forming the coupling teeth of Monoblockschalträder and the stamping surfaces negative teeth ( 20 ' ) having a tooth tip radius (R ') of less than 0.35 mm. Forming tool according to claim 6, characterized in that the forming tool is a Kalibrierpresse for calibrating Monoblockschalträdern. Forming tool according to claim 6 or 7, characterized in that the tooth tip radius (R ') is 0.25 mm or less. Forming tool according to claim 6, 7 or 8, characterized in that it is designed for cold calibration. Monoblock Schaltrad with a ready-to-install clutch teeth, the teeth ( 20 ) with a tooth tip radius (R) of less than 0.35 mm. Monoblock Schaltrad according to claim 10, characterized in that the Zahnkopfradius (R) is 0.25 mm or less.

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