Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D23/00—Details of mechanically-actuated clutches not specific for one distinct type
  • F16D23/02—Arrangements for synchronisation, also for power-operated clutches
  • F16D23/025—Synchro rings
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
  • F16D69/02—Composition of linings ; Methods of manufacturing
  • F16D69/027—Compositions based on metals or inorganic oxides
• • 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

Definitions

• the invention relates to a friction pairing for a synchronizing device in gear change transmissions, in which a synchronizing ring and a coupling ring are directly or via a friction ring arranged on their respective conical friction surfaces, in order to achieve synchronism with each other, form-fittingly coupled drive means, a frictional connection being made, at least one of the friction partners consists of an iron material.
• the gearwheel which is freely rotatable on the shaft, is brought into synchronization with the shaft by axially pressing a synchronizer ring on a coupling ring assigned to the gearwheel, the transmission of the forces being carried out by one on the shaft non-rotatable but axially displaceable sliding sleeve via an axial or radial locking and / or driver teeth on the synchronizer ring.
• the gearwheel is then positively connected to the shaft by further axial displacement of the sliding sleeve, which then engages in a driving toothing of the coupling ring.
• the synchronizer ring has external-conical or internal-conical friction surfaces that come into contact with corresponding mating surfaces on the coupling ring when the synchronizer ring is pressed axially, and produce the synchronism required to maintain the positive clutch by maintaining the frictional flow.
• double a friction ring can be arranged between these friction surfaces.
• Friction linings of this type are known from a large number of prior publications, as the following list shows:
• the mating surface of a friction pair in friction clutches is usually made of steel with a smooth surface and high surface hardness.
• DE-OS 25 38 882 In order to avoid these difficulties during hardening, it has already been proposed in DE-OS 25 38 882 to spray a coating of mangled carbon steel onto the steel counter-cone.
• DE 44 45 898 A1 has disclosed a friction pairing for a synchronizing device of a gear change transmission, in which both friction partners consist of an iron material.
• these similar friction partners must have a wear-resistant carbide-rich edge zone, which is achieved by carburizing and nitriding, nitriding or nitrocarburizing.
• These thermochemical treatment methods of the friction partners make a synchronizing device disproportionately expensive.
• the object of the invention is therefore to provide a friction pairing, the friction partner of which is made of an iron material can be produced as inexpensively as possible.
• this object is achieved according to the characterizing part of claim 1 in conjunction with its preamble in that the iron material has a hardness of 180-350 HV.
• This low hardness makes the thermal or thermochemical treatment required to increase hardness unnecessary according to the prior art. On the one hand, this saves energy and on the other hand, warping of the friction cones does not have to be compensated for in a complex manner.
• the iron material should be designed very widely in the sense of the invention.
• the iron material is an untreated steel, it being clear from claim 3 that this steel is an unalloyed structural steel, an unalloyed case hardening and tempering steel, a low-alloy steel or a high-alloy steel.
• 4 steels of the brands C45, 75Cr1 or 16MnCr5 are mentioned as concrete steel grades. From claims 5 to 9 it emerges that a wide variety of material combinations are conceivable as associated other friction partners. According to claim 5, the second friction partner should have a molybdenum layer.
• molybdenum layers are applied as surface protective layers because they have a high resistance to the adhesion when paired with steel and have a constant coefficient of friction over the entire service life.
• a friction cone provided with a molybdenum coating is described in DE-OS 25 38 882.
• the associated other friction partner is a silicate, an oxide or a non-oxide ceramic material.
• ceramic materials the high hardness and heat hardness as well as favorable wear properties are particularly interesting in this case.
• the expert also knows that ceramics are chemically stable and inert to additives in gear oil.
• ceramics have good emergency running properties if there is insufficient lubrication.
• silicate-ceramic materials are products based on the compounds of silica.
• the technically most important representatives of the oxide-ceramic materials are aluminum oxide Al 2 0 3 and zirconium oxide Zr0 2 .
• Non-oxide ceramic materials include carbides, nitrides, borides and suicides, which are also commonly referred to as hard materials.
• the associated other friction partner can be an iron-based sintered alloy.
• iron alloys are well known to the person skilled in the art and therefore have not been described in detail here.
• Synchronizer rings made of sintered iron alloys can be found, for example, in DE 195 22 473, DE 195 36 188 and DE 198 17 037.
• the associated other friction partner can also be a chromium-iron alloy.
• the advantage Such an alloy partner consists in particular in that it is very temperature-resistant. Such an alloy also has a low tendency to seize and works perfectly even with high surface loads. It is also advantageous that this chromium-iron alloy is very inexpensive. Such a chromium-iron alloy is described in great detail with its advantageous effects and different compositions in DE 135 489 A1.
• the associated other friction partner should be a copper alloy, the term copper alloy also being interpreted very broadly in the sense of the invention. Such alloys have proven themselves for a long time because they are characterized by a good combination of friction coefficient, wear resistance and mechanical strength. Special brasses and bronzes are known to the person skilled in the art. Alloys of this type are sufficiently known from DE 11 54643, DE 12 05 285, DE 16 52 862, DE 44 43666, DE 195 39 498 and DE 195 48 124.
• the single drawing shows a cross section of a friction pairing shown in sections in a synchronizing device for gear change transmissions.
• the synchronizer ring shown in section is denoted by 1 and the dome ring also shown in section by 6.
• the synchronizer ring 1 has the base body 2, which on its inner conical lateral surface before the friction lining 3 is provided.
• the synchronizer ring 1 is provided radially with the driver toothing 4, by means of which it is connected in a rotationally fixed but axially displaceable manner to a shaft via a sliding sleeve (not shown).
• a corresponding toothing of the sliding sleeve engages in the radial drive toothing 7 of the coupling ring 6 for the positive connection of the shaft and coupling ring 6.
• the synchronism between the synchronizing ring 1 and the coupling ring 6 required for the positive connection is established by a cone clutch, ie the synchronizer ring 1 is also included an inner cone and the coupling ring 6 with an outer cone, which have the corresponding friction surfaces 5 and 8, the friction surface 5 being formed by the friction lining 3.
• the friction lining 3 is a molybdenum layer, the friction lining 3 being applied to the synchronizer ring 1 by thermal spraying, that is to say a coating method in which a spray material in the form of wire or powder is melted inside or outside a spraying device is sprayed onto the surface of the synchronizing ring to be coated at high speed.
• the inner cone surface of the synchronizer ring 1 to be coated is not melted or melted on, so that it heats up only slightly during the spraying and therefore no thermal distortion can occur.
• the dome ring 6 belonging to the synchronizer ring 1 is made of 80Cr2 in the present exemplary embodiment, that is to say it has a carbon content of 0.8% and a chromium content of 0.5%.
• the coupling ring 6 is produced without cutting by a drawing process which can be carried out very precisely, so that only an insignificant exciting post-processing is required.
• This coupling ring 6 made of steel has a hardness of 200 HV as a soft part and is used in this form in a synchronizing device. It shows that the measure for the life of a friction pair, namely the course of the coefficient of friction of the iron material as a function of the switching cycle, takes a very favorable course.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Mechanical Operated Clutches (AREA)
• Gears, Cams (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=27797988

Family Applications (1)

Country Status (6)

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Family Cites Families (8)

• 2002
  • 2002-03-21 DE DE2002112489 patent/DE10212489A1/de not_active Ceased
• 2003
  • 2003-03-07 BR BR0303649-9A patent/BR0303649A/pt not_active Application Discontinuation
  • 2003-03-07 WO PCT/EP2003/002329 patent/WO2003081068A1/de not_active Application Discontinuation
  • 2003-03-07 AU AU2003210431A patent/AU2003210431A1/en not_active Abandoned
  • 2003-03-07 EP EP03744789A patent/EP1485630A1/de not_active Withdrawn
  • 2003-03-07 PL PL371039A patent/PL209020B1/pl unknown

Non-Patent Citations (1)

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