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WO2006131355A2 - Denture contenant un materiau fritte adapte - Google Patents

Denture contenant un materiau fritte adapte Download PDF

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Publication number
WO2006131355A2
WO2006131355A2 PCT/EP2006/005475 EP2006005475W WO2006131355A2 WO 2006131355 A2 WO2006131355 A2 WO 2006131355A2 EP 2006005475 W EP2006005475 W EP 2006005475W WO 2006131355 A2 WO2006131355 A2 WO 2006131355A2
Authority
WO
WIPO (PCT)
Prior art keywords
toothing
sintered material
tooth
component
sintered
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2006/005475
Other languages
German (de)
English (en)
Other versions
WO2006131355A3 (fr
Inventor
Gerhard Kotthoff
Volker Arnhold
Vladislav Kruzhanov
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GKN Sinter Metals Holding GmbH
Original Assignee
GKN Sinter Metals Holding GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GKN Sinter Metals Holding GmbH filed Critical GKN Sinter Metals Holding GmbH
Publication of WO2006131355A2 publication Critical patent/WO2006131355A2/fr
Publication of WO2006131355A3 publication Critical patent/WO2006131355A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F5/08—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of toothed articles, e.g. gear wheels; of cam discs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
    • B21H5/00—Making gear wheels, racks, spline shafts or worms
    • B21H5/02—Making gear wheels, racks, spline shafts or worms with cylindrical outline, e.g. by means of die rolls
    • B21H5/022—Finishing gear teeth with cylindrical outline, e.g. burnishing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/16—Both compacting and sintering in successive or repeated steps
    • B22F3/164—Partial deformation or calibration
    • B22F2003/166—Surface calibration, blasting, burnishing, sizing, coining
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/241—Chemical after-treatment on the surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/247—Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/248—Thermal after-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10—Processes characterised by the sequence of their steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H2057/0087—Computer aided design [CAD] specially adapted for gearing features; Analysis of gear systems

Definitions

  • the present invention relates to a component with a surface-compressed toothing of sintered material.
  • Sintered gear elements such as produced by powder metallurgy
  • Gears are used in some areas.
  • the demands on the component due to the toothing often determine the sintering materials to be used.
  • Object of the present invention is to provide a greater freedom with respect to usable sintered materials, with a toothing of the component is taken into account.
  • a component with a surface-compressed toothing of sintered material is proposed, wherein the component viewed over a cross-section, a gradient with respect to used sintered materials.
  • the component has a gradient that has a jump function.
  • the sintered materials are provided with a transition boundary at least in this area. According to one embodiment, this transition boundary is present along the entire surface between the first and second sintered material. Another embodiment provides that in a region there is no fixed boundary but a gradual transition. In particular, it can be provided that the component has different sintered materials which extend into each other without having a pronounced mixing zone of increasing or decreasing gradient.
  • a first development of the component includes that the sintered material of the toothing has a lower core density than the sintered material of a region of the component adjoining the toothing.
  • a second development of the component provides that the sintered material of the toothing has a higher core density than the sintered material of a region of the component adjoining the toothing.
  • a further embodiment has a component which has a first toothing with a first sintered material and has a second toothing with a second sintered material.
  • a toothing has different flank angles on a tooth of the same height.
  • a first sintered material can be arranged in an outer region of the component and form the toothing, and a second sintered material is arranged in an inner region of the component and forms a bore.
  • a method for producing a surface-compressed toothing on a component wherein a first sintered material is introduced into a mold before a second sintered material is added, followed by pressing and sintering and densified by means of a surface compression of the toothing only one of the two sintered materials, while the other sinter material undergoes no change.
  • a further embodiment provides that a second surface compaction is carried out, which relates only to the not yet surface-compressed sintered material. It is preferably provided that the first sintered material forms at least one surface of the toothed edges and the second material forms a relining of the toothing.
  • a further proposed method for producing a surface-compressed toothing on a component provides for introducing a first sintered material into a mold before a second sintered material is added, then pressing and Perform sintering and compacting the first and the second sintered material by means of a surface compression of the toothing.
  • a movement sequence for surface compaction is determined iteratively taking into account a material behavior of at least one of the two sintered materials.
  • a further development for both methods provides that a relative rotation acts between the mold, in particular a press mold, and a sintered material to be filled, so that the sintered material accumulates in an outer region of the mold as a function of a speed of the relative rotation.
  • first and at least the second sintered material are added to the mold overlapping at least over a period of time.
  • a preform of the toothed element is produced with a locally selective oversize relative to a final dimension of the toothed element and rolled to the final dimension by means of at least one rolling tool, wherein the Gear element is compressed locally varies at least in the region of at least one flank and / or a foot of a tooth of the toothed element to produce a compacted edge layer on a surface locally.
  • a toothed element is, for example, a toothed wheel, a rack, a cam, a P-rotor, a ring gear, a sprocket or the like.
  • the compacted sintered material is produced in particular by powder metallurgy methods.
  • a metal powder is sintered under pressure in conjunction with a heat treatment.
  • Plastic injection-molded and in particular under a pressure preferably with a Heat treatment sintered.
  • a sintered mold is used, which has at least almost the endmali of the toothed element to be produced.
  • the preform used is preferably the workpiece resulting directly from the sintering process. In another variant, however, at least one further surface treatment step can also be connected downstream. In this case, the preform has an allowance, which is to be understood as a difference to a final dimension, wherein the difference is preferably defined pointwise perpendicular to the surface.
  • a rolling tool for example, a roller is used, which is provided with a toothing, which is engageable with the toothing of the toothing element.
  • a rolling tool is in particular rolled off under pressure on an outer surface of the toothed element.
  • two or more such rolling tools are preferably used simultaneously.
  • a gear to be produced can be arranged centrally between two rolling tools.
  • first rolling tool under a first pressure substantially for coarse contour rolling and then a second rolling tool under a second pressure to achieve the surface compression to be set in a targeted manner.
  • the locally-selective allowance is in particular dimensioned such that the toothed element is densified locally at least in the area of at least one flank and / or one foot of a tooth of the toothed element in a peripheral layer on a surface.
  • a full density is achieved within the densified edge layer, wherein the full density is preferably based on a density of a comparable powder-forged tooth is to understand.
  • a preform made of a sintered material in a core has a density of at least 6.8 g / cm 3 , preferably at least 7.1 g / cm 3, and more preferably at least 7.3 g / cm 3 .
  • the preform has, for example, a density of at least 7.7 g / cm 3 , preferably of at least 7.8 g / cm 3 , which corresponds to the density of a powder-forged preform of the same material.
  • a load-bearing strength characteristic is achieved particularly advantageously.
  • a highly stressable sintered toothing is preferably provided with a locally variable and load-adapted density profile.
  • the density profile can have a greater degree of density over a larger area, in particular in the areas subject to higher stress, in comparison to areas of lesser load which are directly adjacent to one another.
  • the respective differently densified edge layer is co-produced via a different allowance along a flank and / or tooth bottom of the preform.
  • a depth of the compacted edge layer in each case viewed perpendicular to the surface, has a maximum of the density approximately at the location of maximum stress. This can be, for example, halfway up the tooth and steadily decrease towards the tooth head and tooth root to zero.
  • a particularly high compression in the sintering material is set.
  • other courses can be provided.
  • a force profile on a tooth flank of the toothed element in its intended use is taken into account.
  • the forces acting on teeth of a gear in a transmission are used and the resulting comparison voltage profiles are used below the surface. This procedure is also possible with other dovetails.
  • an allowance on a first flank of the tooth is selected differently than on a second flank of the tooth.
  • a force transmission direction is taken into account in the case of an intended use of a toothed element.
  • this takes into account, for example, that different ones depend on a direction of rotation in the direction of rotation Forces on the tooth flanks occur as counter to the direction of rotation.
  • a different compression due to a direction of rotation of a rolling tool can be compensated.
  • the oversizes are selected such that after a compression process an identical compression profile results along the first and second tooth flanks.
  • a locally compressed surface layer is also sought in these areas. It is particularly useful if an asymmetric allowance is selected in a tooth base. For example, a left tooth root area has a different compression depth than a right tooth root. In particular, between two teeth in each case a preferably continuous variation of a depth of a boundary layer can be provided by a corresponding variation of the oversize.
  • a different, in particular asymmetrical, measure is preferably provided not only with respect to one flank, but preferably with respect to two mutually opposite flanks.
  • a different measure in the tooth root is provided, which is preferably asymmetrical.
  • tooth flanks and tooth roots of a toothing can each be asymmetric.
  • an undersize By this is meant that less sintered material is provided in a Beeich than would have to be provided with respect to a final contour after a processing step.
  • the determined undersize ensures, for example, that no undesired elevations arise when displacing sintered material.
  • the undersize therefore represents a region of a preform with a toothing that is to be replenished by, in particular, displacement of sintered material.
  • the pressure angle of one flank of the tooth may differ by at least 15% from the pressure angle of the other flank of the tooth.
  • At least 20 .mu.m below a surface of a first flank of the tooth is generated by 2% to at least 15% higher density than on a second flank of the tooth at the same height.
  • a density is achieved on the first flank of the tooth, which corresponds at least approximately to the density, which is achieved for a powder-forged toothed element, whereas the second edge has a lower density.
  • at a density in a range between 7.2 g / cm 3 and 7.7 g / cm 3 is set an edge, while in the corresponding region of the second flank has a density between 7.5 g / cm 3 and 7.82 g / cm 3 is set.
  • rotational direction-dependent different loads of the two tooth flanks are taken into account.
  • a requirement-based elasticity and hardness profile is achieved. More preferably, this reduces a noise development, for example in a transmission.
  • a local allowance on a first flank of the tooth is selected larger by at least 10% than an allowance on a second flank of the tooth at the same height.
  • this achieves, for example, that an identical compression course is achieved on the first and the second tooth flank due to different pressure loading during compression as a function of the direction of rotation.
  • a different compression course is achieved on the first and the second tooth flank.
  • different maximum densities, their depths as well as their location in relation to the height of the toothing can be set specifically.
  • an amount of a maximum local allowance is at least 15 ⁇ m, preferably at least 100 ⁇ m and particularly preferably at least 400 ⁇ m. If the density of the preform in a range between 7.2 g / cm 3 and 7.5 g / cm 3 , preferably a maximum allowance between 20 and 150 microns is provided. If the density of the preform between 6.7 g / cm 3 and 7.2 g / cm 3 , preferably a maximum allowance between 50 microns and 500 microns is used.
  • An oversize may also be negative locally, taking into account, for example, a lateral redistribution of material. A lateral redistribution can be done by flowing material as a result of a rolling process.
  • an at least locally negative oversize can be provided, which lies locally below the final dimension.
  • the negative allowance is preferably at most 100 ⁇ m.
  • the negative measurement is at most less than 50 ⁇ m and in particular less than 20 ⁇ m.
  • the maximum negative allowance is in a range between 100 ⁇ m and 20 ⁇ m.
  • a compression is achieved, which reaches a depth between 1 mm and 1, 5 mm, at least in a region of a tooth flank of the toothing.
  • the compression in the tooth root may be lower.
  • the maximum depth of compaction of a tooth flank is greater by at least a factor of 6 than a maximum depth of compaction in a region of the associated tooth root. This allows the toothing on the one hand has sufficient strength, but on the other hand also retains a certain deformability. A tooth breakage is thereby avoided.
  • the preform and the rolling tool are rolled on each other until a final shaping movement between the toothed element produced thereby and the rolling tool is generated.
  • This is used for example for the production of intermeshing gears.
  • a distance between the rolling tool and preform is reduced during the rolling process with the rolling tool. Accordingly, in particular a rolling pressure is adjusted or adjusted.
  • a pure travel control can take place and in another section of the production a pure force control. These can also alternate several times.
  • gear elements in the sense of gears, other gear elements can also be produced.
  • a cam is produced as a toothed element.
  • a cam can be produced, as used for example for the mechanical actuation of an adjusting device, for example for adjusting a valve or the like.
  • an improved strength profile with a lower susceptibility to wear is provided.
  • a further improvement of a surface hardening can be achieved, in particular, by virtue of the fact that the method for producing an at least partially surface-sealed metal toothed element comprises a thermal and / or chemical surface hardening process.
  • case hardening is used as the thermal and / or chemical hardening process. Preference is given here in addition to an increase in hardness, a reduction of tension.
  • a carbonitriding process is used.
  • a nitration or nitrocaboration process as well as a boriding process can be used.
  • a reduction of a strain is also achieved.
  • By adjusting the prevailing pressure can also be influenced on the curing. For example, a vacuum can be set, especially if case hardening is performed. It is also possible to perform an induction hardening.
  • the curing is performed only partially according to an embodiment, for example, made only in the field of teeth.
  • a method for producing an at least partially surface-hardened metal toothed element which has a compacted sintered material comprises the steps "cold or hot pressing, sintering, dimensional and surface compacting rolls and case hardening". For example, at first a cold pressing of a metal powder takes place in a mold which has at least approximately the final dimension of the toothed element to be produced. In a second step, for example, the sintering process takes place under the action of heat with or without pressure. Preferably thereafter, the dimensional and surface compression takes place by means of rollers. As already mentioned above, dimensional and surface compacting rolls preferably take place simultaneously by means of at least two rolling tools. After this, finally, the curing, in particular case hardening can take place, which allows a further hardening of the surface.
  • iron powder is mixed with other preferably elemental powders.
  • elemental powders for example:
  • Distaloy AB, Distaloy 4600A, Distaloy AE, Distaloy 4800A pre-alloyed powders powders of two or more elements that are alloyed during powder production, with uniform distribution of powder particles.
  • Ancorsteel 4600V, Ancorsteel 2000, Ancorsteel 86, Ancorsteel 150HP hybrid alloy pre-alloyed or partially alloyed powders with elemental or iron-alloyed admixtures which are mixed to obtain the desired composition of materials.
  • Ancorsteel 4600V, Ancorsteel 2000, Ancorsteel 86, Ancorsteel 150HP hybrid alloy pre-alloyed or partially alloyed powders with elemental or iron-alloyed admixtures which are mixed to obtain the desired composition of materials.
  • Ancorsteel 4600V, Ancorsteel 2000, Ancorsteel 86, Ancorsteel 150HP hybrid alloy pre-alloyed or partially alloyed powders with elemental or iron-
  • the workpiece has a core density between 6.5 and 7.5 g / cm 3 .
  • the surface density is more than 7.5 g / cm 3 .
  • a maximum density is generated to a depth of 0.1 mm.
  • Starting materials for the preform are sintered metallic powders, in particular pre-alloyed materials, partially alloyed materials or hybrid alloys.
  • a partially alloyed metallic sintered material is a hot pressing at a press temperature in a range between 50 0 C and 80 0 C, a high temperature sintering in a range preferably between 1250 ° C and 128O 0 C, a surface compression, a subsequent vacuum case hardening and honing performed to achieve a final shape of a workpiece with toothing.
  • a hot pressing is carried out, in which preferably the powder and the tool are heated. Preferably these are heated in a range between 120 0 C and 150 °.
  • a sintering step for example as high-temperature sintering, surface compacting and then induction hardening.
  • An aftertreatment can be omitted, for example.
  • the preform is powder forged. This preform is at least partially surface-compacted in the region of the tooth flanks and / or the tooth root.
  • a core density of the workpiece is between 5.7 g / cm 3 and 7.7 g / cm 3 .
  • a surface density in the range of more than 7.8 g / cm 3 wherein preferably in this area all remaining pores are closed at the surface. However, a maximum density up to a depth of 1.5 mm can also be generated.
  • a production process can proceed as follows: choice of powder material, cold pressing of the powder material, sintering preferably with a temperature of about 112O 0 C, connect forging, preferably at a temperature around 1000 0 C, eventually removing an oxidation layer, surface compacting in particular by rolling, Surface hardening, in particular case hardening, and possibly subsequent partial grinding to a final contour.
  • the process can take place completely or partially in a production line.
  • a further embodiment provides that, during surface hardening, a vacuum case hardening is carried out, followed by a honing step for partial regions of the toothing.
  • a preform made of an aluminum-containing material is surface-compacted in the region of the tooth flanks and / or the tooth roots.
  • the core density of the workpiece is preferably between 2, 6 g / cm 3 and 2.8 g / cm 3 .
  • the sintered material is hot-pressed, for example, at a temperature between 40 0 C and 65 ° C, then dewaxed, for example, at a temperature of more than 400 0 C, in particular in a temperature range between 42O 0 C and 440 0 C then sintered, for example in a temperature range above 550 °, in particular in a temperature range between 600 0 C and 630 0 C, then homogenized and cooled, for example to a temperature between 480 0 C and 535 ° C, with subsequent surface densification is carried out in particular by rolling.
  • subse- Oxd curing can take place, for example in a temperature range between 12O 0 C and 185 ° C for a period between 6 h and 24 h.
  • the preform is preferably compressed along the tooth flank and the tooth root, in particular two rolling tools are used, in the middle of which the preform is rotatably arranged.
  • a core density of the workpiece is preferably between 7.2 g / cm 3 and 7.5 g / cm 3 ; depending on the material, a surface density, at least in sections, is greater than 7.8 g / cm 3 .
  • a maximum density is present in particular to a depth of 1 mm, possibly even beyond.
  • a further embodiment provides to compress a partially alloyed sintered material warm, in particular in a temperature range between 50 0 C and 90 0 C to carry out a high-temperature sintering, and in particular in a temperature range between 1240 0C and 1290 0C 1 perform a surface densification, a vacuum - To perform case hardening and possibly then to honing.
  • Another embodiment provides hot pressing a hybrid alloy, wherein the powder and the pressing tool are preferably heated in a temperature range between 120 0 C and 160 0 C. After a sintering step, a surface seal takes place followed by hardening, preferably induction hardening.
  • a pre-sintering follows a surface compression and then again a resintering is provided as a method step in the manufacture of a workpiece with teeth.
  • the pre-sintering can be carried out for example in a temperature range between 650 0 C to 950 0 C.
  • the sintering can be carried out for example in a manner conventional for the material sintering temperature, for example between 1,050 0 C and 118o 0 C.
  • high temperature sintering for example in the range between 1250 0C and 1280 0C
  • Thereafter may optionally curing and / or post-processing, for example honing or grinding.
  • the previous pressing can be done cold, warm or hot, in the latter preferably the pressing tool and the powder are heated.
  • the hot pressing takes place in a temperature range between 12O 0 C and 160 0 C.
  • a further development provides that a subsequent sintering step is followed by a sintering hardening. Optionally, this may be followed by grinding or honing.
  • a further production method envisages compacting the preform at a temperature which is above 150 ° C., in particular above 500 ° C.
  • the preform can be fed directly from a sintering furnace into a surface compacting machine.
  • the preform may have a temperature which is, for example, above 600 ° C., in particular also above 800 ° C.
  • the tool or tools are heated for surface compression, for example to a temperature of about 150 0 C.
  • the tool for surface compaction is cooled, preferably by a running inside the tool cooling.
  • Another production method provides that a surface compression takes place while the preform is at least partially heated.
  • the heating is carried out at a temperature that simplifies the surface compacting.
  • this induction heating is used.
  • rapid cooling is followed by rapid cooling to create a martensitic structure. In this way, for example, a molding process can be combined with surface compaction.
  • a further embodiment of the invention provides that a surface compression can be carried out using a wide variety of methods.
  • One embodiment provides, in particular, that in a first region the surface compression is carried out using a different method than in a second, different region.
  • beam hardening, shot peening, compacting by means of a ball, by means of a roller or by means of another rotatable body, by means of tooth-shaped tools, in particular rolling tools and the like can be used. These methods are also individually separately suitable for allowing a necessary surface densification.
  • the tooth root is not or only slightly compressed with a tool with which the tooth flank is compressed.
  • the surface in To compress a section so far that only the pores are closed at the surface.
  • the tooth root can be processed with another tool or remplinverdichtungshabilit.
  • the maximum surface depth may be different due to the different techniques.
  • the entire workpiece with the toothing receives a surface compression, such as surface blasting.
  • aluminum-containing sintered materials or other oxide-forming sintered materials can also be processed in particular, since surface densification additionally makes it possible to remove an oxide layer.
  • the invention further relates to a preform for a method for producing a metal surface-hardened at least partially toothed element, which has a compacted sintered material, wherein a first and a second edge of a tooth each have different asymmetric dimensions. Furthermore, it is also provided that a first and a second foot region of a tooth have divergent, in particular asymmetrical, measurements.
  • the invention relates to a toothed element with a metallic sintered material, wherein the toothed element has a locally varied compression at least in the region of at least one flank of a tooth of the toothed element.
  • an elasticity of the powder metallurgical material which is suitable for many applications is preferably made possible in conjunction with surface hardening.
  • a noise reduction in the power transmission allows and at the same time provided a good wear resistance.
  • the toothed element is a toothed gear.
  • the toothed element is a helical toothed gear.
  • a bevel gear can be provided. According to the above mentioned Description, it is expedient if opposing flanks of teeth of a toothed element have an asymmetric compression.
  • an asymmetrical compaction is present in a foot region.
  • This compression is adapted in particular to forces occurring during a use according to the application.
  • provision is made in particular for the depth of the locally densified edge layer to be only so high that sufficient elasticity or rigidity of the tooth is still ensured.
  • the depth of the compacted edge layer is less in the foot region than on a tooth flank.
  • the toothed element is a cam.
  • the above statements are to apply accordingly, for example, flanks of the cam occur in place of the edges of teeth.
  • a ferrous material is selected as the main constituent of the sintered material and at least one alloying constituent from the group carbon, molybdenum, nickel, copper, manganese, chromium and vanadium.
  • An iron alloy is, for example, Fe -1, 0 Cr -0.3 V +0.2 based on a reference 15CrNiMo6.
  • Another iron alloy is, for example, Fe -1.5 Mo + 0.2C based on 20MnCr5.
  • the iron-containing alloy Fe -3.5 Mo based on 16MnCr5 is provided.
  • the alloy C may be used 0.2% Cr 0.5% Mn 0.5% Mo 0.5%, with the balance iron and impurity.
  • other compositions may be provided.
  • a surface-compressed toothing made of sintered material has at least 80% aluminum and at least copper and magnesium as further sintering materials.
  • a first embodiment provides that additionally silicon is used as sintered material.
  • silicon may range from about 0.45% to about 0.8%, preferably between 0.6% and 0.75%.
  • silicon may also be present in a higher range, for example between 13% and 17%, in particular between 14.5% and 15.5%. Is the silicon higher proportion, the copper content of the sintered material is reduced.
  • a first mixture may comprise copper at 4% to 5%, silicon at 0.45% to about 0.8%, magnesium at about 0.35% to 0.7%, and the balance at least primarily aluminum.
  • a pressing aid is preferably added. This may be between 0.8 and 1.8%.
  • a second blend may comprise copper at 2.2% to 3%, silicon at 13% to about 17%, magnesium at about 0.4% to 0.9%, and the balance at least primarily aluminum.
  • a pressing aid can be used as exemplified above. After a surface compaction, at least one region of the toothing has a density of, for example, more than 2.5 g / cm 3, preferably up to the maximum density.
  • such a manufactured workpiece with a toothing has a tensile strength of at least 240 N / mm 2 and a hardness of at least 90HB. If the silicon is higher, the density may in particular also be more than 2.6 g / cm 3 .
  • a second embodiment provides that in addition at least zinc is used as the sintering material in addition to copper and magnesium as additives and aluminum.
  • copper has a content in a range between 1.2% and 2.1%, in particular between 1.5% and 1.65%, magnesium between 1.9% and 3.1%, preferably between 2.45% and 2.65%, zinc between 4.7% and 6.1%, in particular between 2.3% and 5.55%.
  • the rest is at least mainly aluminum.
  • a pressing aid as described above can also be used here.
  • a workpiece made from this mixture with a toothing preferably has, after the surface compaction, at least one region of the toothing in which a density of at least 2.58 g / cm 3 extends up to the maximum density.
  • a workpiece produced in this way with a toothing has a tensile strength of at least 280 N / mm 2 and a hardness of at least 120HB.
  • a toothed element is sintered with a further functional component, in particular a shaft or a further toothed wheel.
  • a further functional component in particular a shaft or a further toothed wheel.
  • the toothed element is part of a pump.
  • it is an involute gear, which is brought into engagement with another involute gear.
  • the invention relates to a device for producing an at least partially surface-compressed toothed element, in particular for carrying out a method described above with a tool control adapted to a different allowance.
  • the device comprises in particular at least one rolling tool, which can preferably act on the preform with the aid of the adapted tool control, preferably under an adapted pressure and / or controlled path, in a matched engagement.
  • the device comprises a rolling tool with a toothed surface, which can be brought into engagement with the toothing of the toothing element and can be rolled over thereon.
  • the invention further provides an apparatus for producing an at least partially surface-hardened toothing element from a preform consisting of a sintered material at least in a surface region, wherein the device comprises a tool which compensates for different measurements on a first and a second flank of a rolling movement having to be compacted tooth of the preform.
  • the rolling tool can have a contour necessary for the shaping, for example an involute toothing, only on one flank or on both flanks of a tooth.
  • the invention relates to a method for designing an allowance for achieving a surface compression of a sintered metal toothed element in a rolling operation, wherein the allowance is determined iteratively.
  • a geometry and in particular a torque and / or a pressure distribution is specified.
  • a design of a rolling tool is defined.
  • a preform with a locally defined allowance is determined.
  • a selection can be made using data libraries.
  • Such a data library contains, for example, experimental density profiles determined using various parameters.
  • a simulation of the compression or rolling process can take place.
  • the kinematics of the rolling process in conjunction with a simulation of elastic and plastic properties of the preform and optionally of the rolling tool is simulated.
  • Lation of the elastic or plastic properties of the preform is used, for example, models of continuum mechanics in conjunction with a discrete solution by means of, for example, finite element or finite volume methods.
  • a geometry of a rolling tool is determined iteratively taking into account the oversize. For example, an allowance of an involute toothing of the hobbing tool can be determined. Accordingly, an allowance for other than involute gearing can be determined.
  • a first step at least in a region of a flank of a tooth locally varied, at least pointwise definable allowance of a preform of the toothing element is automatically generated based on at least one design specification
  • a geometry of a rolling tool automatically is generated
  • a rolling process and thereby generated local course of compression of at least one edge layer of the toothed element is simulated
  • an automatic evaluation of the generated course of compaction is compared with a default, and optionally the method from the first step is repeated using at least one variation for optimization until an abort criterion is met.
  • the variation takes place, for example, with the aid of an optimization method.
  • An abort criterion is, for example, a tolerance between the desired density profile and the density profile achieved in the simulation. Furthermore, an abort criterion can also be an exceeding of a predefinable number of iterations.
  • the design specification is to be selected from the group of material density, geometry, torque and pressure distribution.
  • the torque is to be regarded as the torque occurring in the purpose of use of a toothing element used according to the invention.
  • a material tension is simulated, at least in the area of compaction, and used in particular for evaluation. It is preferably avoided that a surface is indeed sufficiently cured, but is brittle due to stresses and tends to stress cracks.
  • data stored for variation in a database library is used.
  • methods for optimization and data analysis can be used, for example, by means of neural networks.
  • features stored in the database are used, for example, for optimization by means of a genetic algorithm.
  • At least one of the steps can be replaced by a default.
  • a rolling tool geometry is fixed. This is taken into account, for example, the fact that a rolling tool is much more expensive to modify, for example, as a preform.
  • Another embodiment provides a reverse approach. Preferably, starting from a final shape, a preform or the rolling tool for producing the final shape as well as the press tool for producing the preform are calculated.
  • the subject matter of the invention is a computer program product with program code means which are stored on a computer-readable medium in order to carry out at least one of the methods described above when the program is executed on a computer.
  • a computer-readable medium is, for example, a magnetic, a magneto-optical or an optical storage medium.
  • a memory chip is used.
  • a computer-readable medium can also be realized by means of a remote memory, for example by means of a computer network.
  • the computer program can be stored, for example, in a machine for surface compaction. Also, a calculation can be made separately from the machine for surface compaction.
  • the machine has a controller, in particular a path and / or force-guided control in which the coordinates and movements can be entered to compact the preform.
  • a die mold with which a preform can be pressed from sintered material, which is subsequently surface-compacted to a final shape.
  • This press tool shape is calculated iteratively.
  • a rolling test stand which offers the possibility of being able to carry out test rolling for a wide variety of surface densifications.
  • the rolling test bench can also have an automated measurement of surface-compacted workpieces which have a toothing.
  • f H ⁇ is the deviation with respect to the toothing
  • F 0 the total deviation
  • f f c is the profile shape deviation of the flanks.
  • the specified values correspond to the DIN classes with respect to the deviation.
  • an iteration takes into account parameters which relate to a material behavior in a surface compression of the tooth form.
  • An embodiment provides that an iteration for determining a preform of input data emanates, which are taken from a specification of the final shape.
  • at least one rolling tool is used, which has the same quality as the final shape created later.
  • the quality of the tool can be transferred to the preform.
  • the extremely accurate surface compaction makes it possible for the toothing to have this quality of the final shape after the surface compacting without any further material-removing post-processing step.
  • a workpiece with the gearing is made to have a core density of at least 7.4 g / cm 3 with a surface density that is at most in a region of a tooth flank, with the maximum surface density extending at least 0.02 ⁇ m in depth in the region ,
  • a method for producing a toothing of compacted sintered material wherein a pre-compressed tooth preform compacted to its final shape at least in one area by means of iteratively determined data and improves roughness in the area opposite the preform by at least 400%, with a surface hardness of at least 130 HB being set.
  • a core density of the final shape is set which has at least a density of 7.3 g / cm 3 and imprinted with a surface hardness having a convex course from the surface toward a center of the final shape.
  • the toothing of precompressed material has, in a first surface-compacted area, a roughness which is at least 400% smaller than a roughness in a second area which is less or not surface-compacted.
  • the roughness R z is, for example, less than 1 ⁇ m in the first region.
  • a further embodiment provides that a surface hardness of at least 700 HV [0.3] is present at the surface of the final shape, while at a depth of 0.4 mm from the surface at least a hardness of 500 HV [0.3] is present .
  • Another embodiment has a surface hardness of at least 700 HV [0.3] on the surface of a tooth flank and in a tooth root, wherein a hardness of at least 500 HV [0.3] at a depth of 0.6 mm from the surface in the Tooth base and a hardness of at least 500 HV [0.3] is present at a depth of 0.8 mm from the surface on the tooth flank.
  • the production of surface compaction makes it possible to set exact compaction as well as hardening according to desired specifications.
  • a calculation method for designing a preform of a toothing made of sintered material wherein data enter into the calculation method, which are determined from a predetermined final shape of the toothing in that one or more load parameters of the gearing are determined in dependence on at least one use condition of the final shape, a local allowance of the preform is calculated which correlates with an expected compaction of the preform at the surface, wherein a loading of the sintering material below the surface into the calculation with received.
  • the calculation is additionally based on penetration of the tool into the workpiece to be produced in the calculation, wherein in particular the behavior of the sintered material during penetration and after penetration can be taken into account.
  • the calculation method provides that an elastic deformation of the sintering material to be compacted is taken into account.
  • the calculation method can provide that an elastic-plastic deformation of the sintering material to be compacted at the surface is taken into account.
  • a depth of a maximum load below the surface for example when the workpiece is used as a force-transmitting gearwheel, enters the calculation method.
  • the calculation method may further include shrinking the sintered material during sintering in the calculation. Also empirically determined data can also be included in the calculation.
  • a calculation method for designing a tool for surface compacting a preform of a toothing made of, in particular, compacted sintered material for producing a predetermined tooth geometry is proposed, wherein determined data from the predetermined tooth geometry to be produced for the calculation of machine tool kinematics, taking into account associated machine parts of a workpiece, from which the tool to be formed is formed, and at least one tool former whose coupled system coordinates and their movement to one another, iteratively included.
  • contact conditions between the workpiece to be produced and the tool former between a tip and a foot of the toothing enter into the calculation method.
  • a maximum stress on the surface is also included in the calculation in the region of one foot of the toothing.
  • a maximum stress below the surface in the calculation with received is particularly suitable for sintered materials, but also for steel workpieces or workpieces made of other materials.
  • a press mold with a press geometry for producing a preform of a toothing made of sintered material is proposed, wherein the press geometry adapted to a surface compression of the toothing course with at least has a survey that generates a recess at least in the region of the toothing of the preform, which can be filled with sintered material during surface compaction.
  • the survey on a front side of the preform causes a depression in the region of a head of a tooth of the toothing.
  • the height of the elevation or depth of the depression as well as other dimensions thereof can be determined.
  • a further embodiment provides, instead of a one-sided survey, that a bilateral elevation is provided in order to effect a depression on both end faces of the tooth.
  • the bump is arranged according to a further development in a region of the geometry which causes a depression on a tooth head of the preform, wherein the bump has a dimension such that the shaped well at least partially grows the tooth head due to the processing of the preform into the final shape by the surface compacting at least diminished.
  • a preform with at least one depression on an end face of a toothing to compensate for a material Aufsches in a surface compression of a tread of the toothing calculate and in particular finished.
  • a preform with at least one depression on a tooth head of a toothing for at least reducing a growth of the tooth head in the amount in a surface compaction at least calculate the flanks of the teeth and in particular finished.
  • the calculation method for determining a geometry of a preform or of a compression molding tool preferably provides that the geometry is determined based on data of a final shape of the preform and at least one depression or elevation is calculated which at least partially effects a compensation of a material displacement during surface compression.
  • a method for surface compaction of a gearing wherein a number of gearing is repeated.
  • the compacting movement of a molding tool for surface compacting a surface on the preform is calculated iteratively.
  • rollover is iteratively calculated until a predetermined surface density is reached.
  • an advance of the molding tool is calculated iteratively.
  • the preform is overrolled less than 20 times to achieve the predetermined geometry of a final shape of the surface compacting. Preferably, less than 10 times the rolling over.
  • overrolling of the preform is performed less than 6 times until a given geometry of a final shape of the surface compacting is achieved. It has to be taken into consideration that with the achievement still no completion of the surface compression takes place. Rather, the tool is then driven on the surface several times, in particular less than 25 times, preferably less than 15 times. As a result, an accuracy of the surface shape is ensured.
  • a method is proposed in which a reversing rolling on a toothing made of sintered material is carried out to densify the preform to the final shape of a surface compacting.
  • a short unloading of the preform is performed by the mold before a reversal of direction. It has been found that by reversing, that is, by reversing the movement, a uniform compaction can be achieved.
  • manufacturing problems were further minimized by reducing the tool's pressure on the workpiece before the motion reversal began. The tool can remain in contact with the workpiece. It can also be detached from the surface for a short time.
  • a surface compression of a workpiece with at least one toothing made of sintered material is proposed, wherein a first surface of the workpiece is compacted with a different method than one second surface of the workpiece.
  • a first toothing of the workpiece has a different compression than a second toothing of the workpiece.
  • a bore in the workpiece, after surface compacting, has a hardened surface and is subsequently brought to a final shape.
  • This allows the use of the bore for a shaft or an axle.
  • An improvement in accuracy can be achieved by surface hardening after hardening of the toothing.
  • a shaft with at least a first and a second toothing wherein the first toothing of sintered material is rolled and surface-compressed.
  • first toothing of sintered material is rolled and surface-compressed.
  • the shaft has a second toothing, which is produced by a different method than the first toothing.
  • the second toothing forms according to a further embodiment with the first toothing a workpiece.
  • both teeth may have been produced together in a press machine.
  • the first and second teeth have been calculated iteratively and prepared accordingly.
  • the production can take place successively, but also simultaneously according to another embodiment. In particular, this also applies to further processing steps such as a surface compaction.
  • the second toothing has a hardened surface without surface compaction.
  • the density inherent in sintering or the inherent strength of the material used is sufficient. This applies, for example, for pump applications.
  • the first toothing has at least one tooth each different edge slopes at the same height of the tooth. This is advantageous in applications in which a main direction of rotation and in particular only one direction of rotation of the shaft is predetermined.
  • the different flank slopes can thus be designed to reduce wear and noise.
  • the second toothing is forged. It can additionally be surface-compacted. For example, this toothing can absorb a greater force transmission than the first toothing.
  • the second toothing is made of a different material than the first toothing.
  • the second toothing is made of steel.
  • the second toothing can also consist of a different sintered material than the first toothing.
  • the shaft may also be made of sintered material. It may, for example, have the same material as the first toothing.
  • the shaft can be formed at least together with the first toothing, i. be pressed from powder material, preferably in a common mold.
  • An exemplary method for producing the shaft described above may also provide that at least the first gearing receives a surface compaction and a bore for receiving the shaft is surface-compacted, hardened and then honed before the shaft and the first gearing are joined together. For this purpose, preferably, starting from an end shape of the shaft with the first toothing, an iterative calculation of a preform of the first toothing takes place.
  • a preform for producing a toothing made of sintered material is used, wherein the preform has a negative allowance.
  • the negative allowance is arranged at least on an edge of a tooth of the toothing.
  • the negative allowance can run asymmetrically along the flank.
  • a negative measure is proceed.
  • a tooth at the same height has a first negative allowance on a first flank and a second negative allowance on a second flank, wherein the first flank and the second flank extend asymmetrically relative to one another.
  • the negative allowance is located between a head portion of the tooth and a measure on a flank of the tooth.
  • the negative allowance can be arranged in a corner region of the tooth root.
  • a development provides a method for producing a toothing of a sintered material, wherein a preform is assigned at least one determined by iterative calculation negative allowance, which is at least partially filled in a surface compression of the toothing by displacement of the sintered material. Preferably, an oversize material adjacent to the negative allowance is displaced into the negative allowance.
  • the preform may be surface-compacted into the desired final shape, optionally with curing and / or surface finishing. This can be done before or after surface compacting. As a fine machining honing as well as a grinding is considered.
  • the design of the negative amount takes place via an iterative calculation, in which a simulation of the surface compaction on the preform determines whether the adjacent allowance of its shape is designed so that the negative allowance can be smoothed towards the desired final contour.
  • a machine for calculating and / or performing a surface compaction of a toothing is provided, wherein a calculated kinematics is einar, by means of the surface densification a negative allowance on a flank of the toothing can be smoothed to a desired final contour.
  • a method for producing a surface compaction on a toothing wherein at least two preforms simultaneously receive surface compaction in a device.
  • the preforms are arranged on parallel shafts and at the same time engage with at least one tool for surface compaction.
  • At least two preforms are arranged on a common shaft and jointly brought into engagement with at least one tool for surface compaction.
  • an apparatus for producing a surface compaction on a toothing wherein at least two preforms for surface compaction in the device are durable and can be processed simultaneously.
  • a movement of at least one shaft in which both preforms come into engagement with a tool for surface compaction.
  • at least three shafts for at least two preforms and at least one tool are arranged parallel to one another and form a triangle, wherein at least one of the shafts can be moved toward the other two shafts.
  • at least two preforms can be attached to a common shaft, wherein the tool has a greater length than an added length of at least both preforms.
  • the preforms can lie with their end faces together.
  • a distance is arranged between the preforms, the tool protruding along the shaft over both outer end faces of the preforms.
  • the manufacturing process also provides grinding or honing of the compacted tooth flanks and / or tooth roots in addition to the surface compacting step of the toothing.
  • the forging achieves a density of at least 7.6 g / cm 3 as the core density.
  • the surface compacting can therefore cause a full compression and / or a precision of the shape of the toothing.
  • an oversize for this step in a range of 4 ⁇ m to 8 ⁇ m material is above the final dimension for a material-removing machining step after surface compacting.
  • honing is preferably 30 ⁇ m to 50 ⁇ m and for grinding 50 ⁇ m to 0.3 mm, preferably 0.1 mm to 0.2 mm after surface thickening provided.
  • the iterative calculation makes it possible to determine the areas and dimensions beforehand and to be able to implement them later in the procedure.
  • surface compacting is preferably also provided, followed by hardening followed by preferably honing.
  • the bore may also have an oversize between 30 ⁇ m and 50 ⁇ m after surface compacting.
  • lubrication occurs during surface compacting.
  • emulsions can be lubricated in particular with oils. This is preferred in a hot rolling, for example at temperatures above 220 0 C.
  • Fig. 8 shows a first process scheme
  • FIG. 11 is a schematic view of a calculated depression on an end face
  • FIG. 12 shows a schematic view of calculated extreme cases of tools
  • FIG. 13 shows a schematic view of an approach during the iterative calculation and links in a simulation
  • FIG. 15 shows an overview of the detected errors which occur with different surface compacting steps and characterize the material behavior
  • FIG. 17 shows a hardness profile in HV in a foot region of a toothing in the case of different surface densification steps
  • FIG. 18 shows a schematic view of different calculated measurement curves for different densities
  • 19 is a schematic representation of parameters that can be included in the iterative calculation.
  • Fig. 1 shows an exemplary Wälzan eleven in a schematic view.
  • a first rolling tool 101 with a first toothing 102 is rotatably mounted about a first axis 103 in a direction of rotation 104.
  • the first toothing 102 is engaged with a second toothing 105 of a preform 106.
  • the preform 106 is rotatably mounted about a second axis 107. Accordingly, a second rotational direction 108 results.
  • the second toothing 105 is engaged with a third toothing 109 of a second rolling tool 110.
  • This second rolling tool 110 is rotatably mounted about a third axis 111 in a third rotational direction 112.
  • the first axis 103 or the second axis 107 may be fixed axes, while the other two axes may perform a feed motion.
  • the third axis 111 is displaceable in a displacement direction 113 along a connecting line 114 of the first 103, the second 107 and the third axis 111.
  • a doctorwalzvorgang be made.
  • tooth flanks are only slightly compacted and, in particular, the tooth roots are not compacted. This results in a surface compaction in a desired area.
  • the tooth base can also be surface-compacted only or additionally.
  • a progressive displacement in the direction of the displacement direction 113 takes place.
  • a region of the tooth roots of the preform 106 is also compacted.
  • an adjusting device is preferably provided with a provided nem transmission. In particular, very high pressures can be applied.
  • FIG. 2 shows a first tooth 201 of an associated toothing element (not shown).
  • This toothed element is a toothed wheel.
  • a geometry of the toothed element or the first tooth 201 is characterized by a first root circle 202, a first root circle 203, a first pitch circle 204 and a first tip circle 205.
  • the first tooth 201 On a first flank 206, the first tooth 201 has a first flow path 207 before a rolling process. After a completed rolling operation results in a first End configuredverlauf 208, whereby a first compacted edge layer 209 results accordingly. Schematically, this is limited by a first compression boundary line 210. This line limits the area of the first tooth 201 within which full density is achieved. The full density is preferably based on a density of a comparable powder-forged tooth.
  • Fig. 3 shows a second tooth 301 of a toothed element, not shown.
  • This toothed element is also a gear wheel.
  • Second tooth 301 and gear are characterized by a second tip circle 302, a second pitch circle 303, a second root circuit 304 and a second root circle 305.
  • a second oversize course 308 and a third oversize course 309 are provided.
  • a rolling operation results on the second edge 306, a second End configuredverlauf 310 and on the third edge 307, a third End configuredverlauf 311. Furthermore results in a second compression boundary line 312 and a third compression boundary line 313.
  • the second oversize 308 and the third oversize 309 are designed differently.
  • the different action of forces on the tooth flanks 306, 307 during a rolling process is illustrated by the illustrated sliding speed directions.
  • a first 314 and a second sliding speed direction 315 result. These are directed from the second pitch circle 303 in the direction of the second tip circle 302 and in the direction of the second root circle 305, respectively.
  • On the third flank 307 results in a third sliding speed direction 316 and a fourth sliding speed direction 317, which are directed against each other.
  • Fig. 4 shows a third tooth 401 of a toothed element, not shown.
  • This toothed element is also a gear wheel.
  • Gear and third tooth 401 are in turn characterized by a third tip circle 402, a Kopfnutz Vietnamese 403, a third pitch circle 404, a third penalnutz Vietnamese 405 and by a third vis Vietnamese 406.
  • third tooth 401 is a toothing with a tip retraction, preferably in the form of a head rounding.
  • a tooth profile is withdrawn in a tooth head region 401.1 between the third head circle 402 and the head cycle 403. As a result, the tooth does not engage in involute counter-toothing in this area. In this case, there is an active one
  • a fourth Aufbornverlauf 407 results after a rolling process in a fourth compression boundary line 408. Furthermore, on the fourth edge 409, a fourth End liberverlauf 410 achieves.
  • Fig. 5 shows a Aufbornverlauf between two adjacent teeth of a toothed element, not shown.
  • This toothed element is again a toothed wheel.
  • the gear and teeth are characterized by a fourth root circle 502, a fourth root base footpath 503, a fifth landback circle 504 of the preform after a grinding operation, a fourth head circle 505 after a milling operation, and a fifth head circle 506 after a finishing operation.
  • After a rolling operation results in a fifth Endemblverlauf 507.
  • On the abscissa axis a lateral dimension in millimeters is plotted.
  • On the ordinate axis, the correspondingly perpendicular lateral dimension is also plotted in millimeters.
  • the teeth run completely in the plane of the drawing.
  • Fig. 6 shows a compilation of further Aufforceveryear.
  • the nominated floor length along a flank line of a toothed element is shown on the abscissa axis.
  • this curved line relates to a progression from a tooth tip of a first tooth to a tooth tip of an adjacent tooth.
  • the absolute arc length of the corresponding flank line in millimeters is correspondingly shown on the upper abscissa axis.
  • the left ordinate axis indicates an allowance in millimeters.
  • the right ordinate axis describes the corresponding radius of the corresponding toothing. Shown are a sixth oversize profile 601, a seventh oversize 602 and an eighth oversize 603. Furthermore, an associated radius 604 of the corresponding illustrated toothing.
  • the sixth oversize profile 601 and the eighth oversize profile 603 are in this case implemented symmetrically with respect to a tooth base symmetry line 605.
  • the seventh oversize profile 607 is designed asymmetrically. In the vicinity of the tooth symmetry baseline 605, that is to say in the tooth base region, the oversizes each have a local minimum. This promotes a reduction of a risk of stress cracking.
  • Fig. 7 shows a further Aufbornverlauf. Shown is a ninth oversize progression, which runs asymmetrically from a left tooth head 702 to a right tooth head 703. As already shown in FIG. 6, an oversize in the area of a tooth root 704 is smaller here than in the area of the fifth 705 and the sixth flank 706. This serves in particular to avoid stress cracks.
  • Fig. 8 shows a first process scheme.
  • a geometry of a rolling tool is generated with a first geometry generation module 802.
  • a geometry of a preform in a second geometry generation module 803 is generated based both on the target 801 and on the geometry of the rolling tool.
  • a rolling process is simulated. In this case, both a kinematics of the rolling process and the compression process, which is caused during rolling, simulated.
  • a redistribution of material as outlined for example in FIG. 3, is taken into account.
  • the simulation of a plastic deformation takes place here for example by means of a finite element method.
  • a second simulation module 805 for simulating a stress can be considered. Both the target 801 and the preform geometry are included in this module. On the other hand, the second simulation module 805 further enables correction of the detected geometry of the preform.
  • the first geometry generation module 802, the second geometry generation module 803, the first simulation module 804, and optionally the second simulation module 805 may be repeatedly executed in an optimization loop.
  • Fig. 9 shows a second process scheme.
  • a ninth oversize profile 902 of a tooth profile 903 is generated.
  • a second tooth profile 905 of a third rolling tool 906 is generated.
  • a rolling process is simulated.
  • the rolling process of the first tooth profile 903 on the second tooth profile of the rolling tool 905 and the resulting compression is simulated.
  • the first, second and third steps 901, 904, 907 are optionally repeated in a variation 908.
  • FIG. 10 shows an oversize profile of a toothed element of a rolling tool. Shown is a tenth Aufbornverlauf 1001 of a fifth tooth 1002 of a rolling tool, not shown. At a seventh flank 1003 and an eighth flank 1004 of the fifth tooth 1002, a different allowance is provided. At the seventh
  • Flank 1003 is a material allowance is provided, which is indicated by a first arrow 1005.
  • a tooth return is provided on the eighth edge 1004, which is indicated by the second arrow 1006.
  • the allowance in this example is based on a regular profile of involute toothing. Due to the asymmetrical configurations of the two tooth flanks 1003, 1004, in particular an asymmetrical material loading of a toothed element to be compacted therewith is taken into account. Also, with respect to the final shape of the workpiece a symmetrical profile of both flanks of a tooth can be achieved by means of this rolling tool, for which compensations in the range of preferably less than 0.1 microns are made.
  • FIG. 11 shows a schematic view of a calculated depression on an end face of a toothing.
  • the depression serves to at least minimize, if not even compensate, growth of the sintering material displacement achieved by the surface compaction and concomitant growth of the tooth in height and / or width.
  • the shape of the depression depends on the allowance and on the dimensions of the tooth. The shape can be optimized iteratively using the calculation method. A simulation allows an estimation of the actual behavior of the preform later on.
  • Fig. 12 is a schematic view of calculated extreme cases of surface compaction tools which are calculable.
  • the starting point of the calculation is the left-hand end geometry of the toothing.
  • 13 is a schematic view of a procedure in the iterative calculation and links in a simulation. Based on the given end data of the workpiece and its toothing, the machine kinematics can be modeled. In this case, for example, the machine axes assigned to one another are assumed. By means of the kinematics and functional links, an optimization of the tool to be designed can then be carried out by means of the available degrees of freedom. Reference is again made to FIG.
  • Fig. 14 shows a view of density gradients as a function of different initial densities of the preforms used. If the density of the preform in its core as well as in the course changed outward, there are influences on the surface densification course. This is shown in the right-hand illustration of FIG. 14. By changing the respective preform, the density profile after a surface compression can also be strongly influenced. Therefore, the output core density as well as the shape of the preform are important parameters in the iteration and computation.
  • FIG. 15 gives an exemplary overview of the detected errors which occur at different surface densification steps and characterize the material behavior.
  • the error is specified in error classes according to DIN 3972 or DIN 3970.
  • An important point in determining a suitable surface compaction by rolling is the profile change of the rolling tool.
  • Fig. 15 at a preform having a core density of 7.3 g / cm 3, which was in engagement with an unmodified set of rolling tools and has been surface compressed.
  • the geometry of the gear changes. The goal is to achieve the desired final contour, as it is prescribed. From the figures of Fig.
  • a new tool can then be determined, again perform the tests and iteratively determine an optimized geometry for the tool in this way.
  • the calculation makes it possible to determine a final contour for the tool with, for example, two or even one iteration.
  • FIG. 16 shows a hardness profile in HV plotted on a flank of a toothing over the distance from the surface on the x-axis in [mm].
  • the profile profile of the hardness can be influenced by suitable dimensioning as well as by feed movement.
  • the course may be at least partially convex or concave.
  • the preform designated AVA7-1 has a larger oversize than the preform designated AVA4-2. Both have an opposite course of hardness: while in the first part until reaching 550 HVAVA7-1 has a more convex shape, AVA4-2 has a more concave course. After falling below 550HV this changes.
  • FIG. 17 shows a hardness curve in HV in a foot region of a toothing in various surface compacting steps. Due to the smaller oversize there compared to the flank allowance and due to the geometry results in a different hardness profile. The hardness initially drops steeper, but then goes over almost in a straight course with only a slight inclination.
  • FIG. 18 shows a schematic view of various calculated scale curves for different densities based on a final tooth thickness.
  • the diameter is plotted on the y-axis.
  • the oversize is indicated on the x-axis.
  • D_a or d_a indicates the head circle diameter or the tip circle diameter
  • 0 is a predetermination of an amount, for example, by a value on the pitch circle
  • d_b is the base circle diameter.
  • A indicates the range of preferred values for the pitch circle area.
  • B gives a critical area again, since there may already occur material failure during rolling.
  • FIG. 19 shows a schematic representation of parameters that can be included in the iterative calculation.
  • these locations may be the maximum load.
  • a comparison voltage curve is preferably used in which the following applies: A maximum voltage occurs below the surface, in particular in the region of a negative slip, therefore preferably below the specified rolling circle diameter d_w1.
  • the right photo indicates a tooth fracture due to excessive bending load. It follows for the calculation model that a location of the maximum Zahnfußbe pipeung is determined and taken into account. This can be determined, for example, via the 30 ° tangent according to DIN or via the Lewis parabola according to AGMA.
  • For the comparison voltage it is preferably assumed that a maximum stress occurs on the surface.
  • FIG. 20 shows, in a schematic view, a further possibility of, for example, simultaneously being able to compact at least two preforms.
  • a movement of the preforms in the direction of the tool can be carried out.
  • the invention can be used, for example, in camshaft toothed wheels, in planetary gears, in sun gears, in drive gears, in compensating gears, in gear wheels, clutch gears, pump gears, spur gears, helical gears, electric motors, internal combustion engines, in variable transmissions at External or internal gears, with straight or helical gearboxes with straight or helical gearing, with bevel gearboxes with straight, helical or curved gearing, with helical gearboxes or worm gearboxes, as well as with helical and helical hub connections.
  • a gear made of sintered metal The other may be made of plastic or another material, for example.
  • At least one of the two gear wheels has a coating which in particular has a noise minimizing effect.
  • a Kegelschraubradcru can be created to thereby form a Hypoidgetriebe.
  • the workpieces are interlocking with me in the automotive industry, in the motor rentechnik, in transmission technology, in adjusting devices, in power transmitting devices, in toys, in precision mechanical devices, household appliances, especially mobile home appliances, and other applicable.

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Abstract

La présente invention concerne un composant présentant une denture densifiée en surface, réalisée en matériau fritté. En vue transversale, le composant selon l'invention présente un gradient en ce qui concerne les matériaux de frittage employés.
PCT/EP2006/005475 2005-06-10 2006-06-08 Denture contenant un materiau fritte adapte Ceased WO2006131355A2 (fr)

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DE102005027140A DE102005027140A1 (de) 2005-06-10 2005-06-10 Verzahnung mit angepasstem Sintermaterial

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FR3034833B1 (fr) * 2015-04-13 2019-01-25 Valeo Equipements Electriques Moteur Pignon de demarreur pour moteur thermique de vehicule automobile a performances mecaniques ameliorees

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Publication number Priority date Publication date Assignee Title
US11060595B2 (en) 2017-01-05 2021-07-13 Gkn Sinter Metals, Llc NVH modification for differential assembly

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DE102005027140A1 (de) 2006-12-14

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