DE102013107347A1 - design element - Google Patents

Abstract

Construction element for friction-enhancing play-free reversible connection of workpieces to be joined, consisting of a substrate having on its surface hard material particles of defined size, wherein the hard material particles are fixed by means of a metallic binder phase of a chemically deposited nickel / phosphorus alloy on the substrate, and wherein the substrate Has inherent strength, which is lower than that of the workpieces to be joined and its use.

Description

The present invention relates to a construction element for friction-enhancing play-free reversible connection of workpieces to be joined and its use.

Today's requirements in the field of mechanical engineering mean that the structural elements have to transfer ever higher forces in the smallest possible space for reasons of economy and further development.

Against this background, there is a constant effort in research and industry to shift the limits of the transferability of non-positive connections between the joining partners, determined by the validity of Coulomb's friction law, by the use of friction-increasing coatings in new sizes.

The first considerations with regard to friction-increasing coatings go back to the early days of mechanical engineering. As early as 1860, it was recommended to spread sand into the joint gap of shrink joints in order to improve the fit of gears and waves.

This method is no longer applicable to today's mechanical engineering, especially in view of the increased demands in terms of tolerances and reproducibility of series components.

Another principle for increasing the transfer capability of non-positive connections is based on the assumption that one of the two joining partners to be joined is directly coated with a friction-enhancing layer to increase the static friction.

So is for example from the DE 23 64 275 It is known to apply a hard material-containing layer to one of the two interacting surfaces by vapor deposition, spraying, sintering or diffusion of a foreign substance into the component surface. In the publication "Surface Layers for Non-positive Momentum Transfer" by H. Peeken, J. Lukschandel et al. in drive technology (20), 1981 , is achieved by galvanic deposition by co-deposition of fine hard grains with a metallic binder phase on nickel / phosphorus-based friction-enhancing coating. The static friction of a shaft-hub-shrink connection is thereby more than doubled. These layers allow for even better adhesion coefficients with circumferential bending stress than with purely static loading.

These methods, to provide only one of the surface to be joined with a friction-increasing coating, have the disadvantage that the friction-increasing coating can not be applied to both joining partners for procedural reasons.

Other disadvantages of these methods are to be seen in their technical feasibility, because large complex assemblies or parts that are arranged on large elements, can not be so selectively refine, as required from a joining technical point of view.

To circumvent this problem, the workpieces to be joined were non-positively connected via a construction element located in the joint gap, which consists of a carrier material and hard material particles applied thereto by means of various methods.

So is from the patent CH-PS 192 197 known to use paper or linen as a flexible carrier material for a coating applied on both sides, containing hard material particles layer.

As a mechanism of action for increasing the adhesion, a mechanical superimposition of wedge-shaped hard material particles by relative movement of the components to be joined is described.

Also the JP 6-147206 discloses paper or linen as a flexible carrier material for hard grains.

The design elements mentioned in the documents are not able to transmit high lateral forces. They are therefore unsuitable for many applications.

Furthermore, in the US-A-4 525 098 . US-A-4 154 276 . US-A-3,828,515 or US-A-3,692,341 described to position an easily deformable material low intrinsic strength with it applied hard grains in the joint gap frictional connections. When joining or pressing the components penetrate the Hard material particles in both surfaces and transmit the occurring shear forces directly, without the carrier film is involved in this force transmission.

Although such compounds have the advantage of being releasable on a case by case basis, however, the particles which have penetrated into the joining surfaces remain uncontrollably stuck in one of the surfaces of the joining partners. The reproducible reuse of the once dissolved compound is not possible.

Another option is in the DE 31 49 596 A1 disclosed in which a compound is prepared by means of coarse hard body. It is described the use of an elastic support film made of a deformable material that does not participate in the transmission itself.

Disadvantageously, this connection is insoluble and thus does not allow a reversible connection of the workpieces to be joined.

Soluble compounds using hard particles to increase power transmission or to increase the coefficient of friction between two waves using an integral component are known from DE 32 37 096 A1 previously known. There, two shafts are connected, between which a disc is arranged, wherein the two shafts are rotatably connected by the pressure of a clamping screw with each other. The disk forming the integral structural element has so-called emery layers on its substrate surface, which are fastened by means of a nickel layer. The embedded in this nickel layer hard particles penetrate by the pressure of the screw in the surfaces of the waves and thus form a rotationally fixed connection between these parts.

The principle of increasing the coefficient of friction over the so-called "microforming" is detailed in the DE 94 02 867 U1 disclosed. There disclosed is a holding element for tools, workpieces or machine elements, etc., with which even at low contact forces exceptionally large holding forces and moments can be transmitted and with a particularly rigid, releasable connection between parts in any position of the parts is achieved.

For this purpose, the pressure surface on an adhesive coating of diamond grains, which protrude from a binder metal layer of a galvanically applied nickel coating on the holding element. The diamond grains deform when pressing the pressure surface against the counter surface this only in the elastic range. By this micro deformation in the mating surface of the coefficient of friction between this and the pressure surface is extremely high, because by the protruding into the micro-deformations grain peaks between the pressure surface and the counter surface creates a kind of positive connection with geometrically indeterminate elements.

Recently, the development in the direction of maximum power density of machine components, especially in the automotive industry has meant that even with critical parts in the field of engine development, for example in highly torsionally loaded connections between the crankshaft and vibration damper including synchronization disc, the performance increases of up to 30% could be achieved only with such frictional joint connections using structural elements coated with hard materials.

A specially designed for this purpose construction element is in the EP 0 961 038 B1 described. It consists of a spring-elastic foil of metallic material, wherein the elastic foil has on its surface hard material particles of defined size, which are fixed by means of a nickel / phosphorus layer.

The load applied to this structural element, friction diamond coating is sold under the name EKagrip ^®.

Furthermore, in the EP 0 961 038 B1 a shaped body claimed, comprising 2 workpieces and the aforementioned construction element, wherein the inherent strength of the elastic film is at least as high as the intrinsic strength of the workpieces to be joined; the hard particles consist of a material with a compressive and shear strength which exceeds that of the workpieces to be joined; and the particles are embedded in a binder phase having a strength at least equal to that of the surfaces of the workpieces to be joined.

The main disadvantages of in the EP 0 961 038 B1 disclosed construction elements are in the article "Friction-enhancing surface layers for torsional stresses" by E. Leidich, J. Lukschandel et al., Antriebstechnik (40), 2001, pp. 53-57 , described. There it is stated, among other things, that the elastomeric construction elements coated with EKAGRIP ^® tend to break during a surface pressure of 100 MPa during torsional loading.

Furthermore, microcracks in the elastic film are reported, which are induced by the penetration of the diamond particles into the "comparatively soft" elastic steel foil. Again, there is a risk of breakage due to continuous torsional shear stresses.

A failure caused by a microcrack or even fracture of such a structural element would inevitably cause a major engine failure. In view of the ever stricter product and producer liability, such a risk is not sustainable for the automotive industry.

Another solution describes the EP 1 564 418 B1 , Here, in contrast to EP 0 961 038 B1 not elastic, but elastic plastic steel foils and no rounded or spherical hard particles (such as diamond grains) are used in the binder matrix to minimize the risk of microcracks or fractures.

Both the inventive idea of EP 0 961 038 B1 as well as the EP 1 564 418 B1 is based on the fact that the steel substrate on which the hard particles are applied by means of a chemical nickel layer, have an intrinsic strength that is not lower than that of the workpieces to be joined.

This feature is intended to ensure that the hard material particles do not press into the steel substrate but into the workpiece to be joined (counter-body) during large force transmissions or contact pressures.

In this way, a micro-gearing effect is to be achieved, which ultimately leads to an increased power transmission - illustrative examples of this micro-gearing effect are in the article of Peeken, Lukschandel and Paulick, "Surface layers for non-positive torque transmission", in "ant - Antriebstechnik, January / February 1981" The lack of penetration of the hard material particles into the steel substrate is mentioned as the main argument for reducing the risk of microcracks.

Object of the present invention is to provide a construction element, which in view of the described prior art, a relatively frictional connection torsionsschubbelasteter components without the risk of breakage under the in the article of E. Leidich, J. Lukschandel et al. described test conditions, but further requires no restrictions on the selection of hard material particles. The present invention is intended to allow a broader and more personalized application spectrum for the particular application.

This object is achieved by a construction element of the type mentioned, d. H. a construction element for friction-increasing play-free reversible connection of workpieces to be joined, consisting of a substrate having on its surface hard material particles of defined size, wherein the hard material particles are fixed by means of a metallic binder phase of a chemically deposited nickel / phosphorus alloy on the substrate, characterized in that the substrate has an inherent strength which is lower than that of the workpieces to be joined.

This solution makes it possible for the first time to use rounded or spherical hard-material particles (such as diamond grains) as hard materials and "soft" substrates, without the risk of breakage being observed in corresponding experiments.

Such a construction element according to the invention allows in comparison to EP 1 564 418 similar friction increases. Even under a preload of 100 MPa showed a 0.1 mm thick disc according to the invention, which was dynamically biased with 10 ⁷ load changes, under the test conditions described above no break.

For highly stressed compounds in mechanical engineering, the workpieces to be joined are usually those having an intrinsic strength of more than 500 N / mm ² , in particular more than 700 N / mm ² . Examples of such materials are steels of various alloys and surface treatments, depending on the desired application.

Accordingly, the substrates to be used according to the invention have a lower inherent strength, particularly preferred are substrates having an intrinsic strength of less than 400 N / mm ² , in particular less than 200 N / mm ² . In a further, likewise preferred embodiment, the substrate has an intrinsic strength of less than 80% of the workpieces to be joined, in order to effectively reduce the formation of cracks.

It is surprising and unpredictable that the coating element according to the invention even leads to an increase in the friction property and a micro-toothing effect can be observed in the workpieces to be joined, even in the case of a substrate having a substantially lower intrinsic strength. Because both the EP 0 961 038 B1 as well as the EP 1 564 418 B1 teach that the intrinsic strength of the substrate must be at least as high as that of the workpieces to be joined to prevent penetration of the hard material particles into the metal substrate disclosed therein.

The exact background of this crucial property of the construction element according to the invention are not yet clear. Initial studies show, however, that the binder phase from the deposited on the substrate chemical nickel layer plays a crucial role.

So far, a chemically deposited nickel layer due to their particularly sharp contours and faithful reproduction in very close tolerances and the properties of the resulting matrix (higher hardness, improved ductility, and in view of the high mechanical requirements in the range of shaft / hub connections much more favorable elastic modulus ).

The results with rounded diamond grains show that possibly the sharp-edged toothing of the hard particles in the counterbody (microforming) is more of a theoretical thinking model. Possibly already sufficient a comparative "gentle impressions" not sharp-edged hard particles in the flat surface of the Zufügenden workpiece in order to ensure an effective and increased power transmission in the context of the prior art.

The use of non-sharp-edged hard material particles has a particular advantage: Even after repeated loosening and reconnecting using the construction element according to the invention, significantly less hard material particles are torn out of the binder matrix and remain stuck in the workpiece to be joined.

According to a particularly preferred embodiment, the substrate is a metal substrate made of a light metal or its alloys, aluminum, an aluminum alloy or a stainless steel alloy.

For the first time, materials can be used which, in addition to the steel substrates described in the prior art, bring along further special properties. Alloy or aluminum substrates have a significant advantage in terms of long-term corrosion properties. Stainless steel substrates, on the other hand, are characterized by their special toughness properties.

Most preferably, the metal substrate is selected from a copper-containing aluminum alloy, in particular from the alloys AlSiCu 1.5 (7050) or AlZnMgCu1.5 (7075) ENAW7075, AlZn4.5Mg1 (7020) 3.445 AW7020, AlCU4Mg1 (2024) ENAW2024 or X5CrNiMo1808 ( 4301). In particular, corrosion properties with mechanical toughness are paired here. According to a further, likewise preferred embodiment, the substrate is a plastic, in particular a polyester-bonded thermoset, on which a metal layer is applied. Apply metal layers on a plastic substrate are known in the art. Very particularly preferred according to the invention is a metallization process in which the plastic surface is roughened in a targeted manner and subsequently metallized by means of various steps. This special process is known under the name METACOAT ^{O from} the company AHC Oberflächentechnik - in this regard, reference is made to the applications WO 2004/092436 A1 . WO 2004/092256 A1 . WO 2004/092445 A1 . WO 2004/092444 A1 and WO 2004/091906 A1 , the disclosure of which is hereby incorporated into this application. The main advantage of using metallized plastic substrates according to the METACOAT ^O method is that an extremely adherent metal layer is achieved and that the shear stress can be represented.

According to a further, likewise preferred embodiment, the substrate is a metal substrate made of a brass or bronze alloy. The construction element according to the invention which is obtainable in this way is used wherever non-magnetic properties play a special role.

The hard material particles are selected from the group of diamond, silicon carbide or tetraborcarbide. The geometric shape is not critical. Both sharp-edged and rounded hard material particles can be used according to the invention. Rounded particles are to be preferred if the compound to be joined is to be dissolved several times. In the case of connections which are not or only rarely solvable, it is also possible to use sharp-edged particles which, in contrast to rounded particles, are more industrially available and cheaper.

The hard material particles preferably have a diameter of not more than 19 μm. This diameter is an upper limit for still sufficient force transmission and an effective prevention of the penetration of the hard material particles into the metal substrate in the sense of the invention. Preferably, such hard material particles are used whose mean particle size distribution is between 19 and 14 .mu.m ± 1.5. Screening methods, laser diffractometry or microscopic evaluations can be used as measuring methods to determine the particle sizes.

In a preferred embodiment, the metal substrate according to the invention has a thickness of less than 0.5 mm, in particular less than 0.2 mm. As a result, a simple exchange with known construction elements of the prior art is made possible without structural changes to the workpieces to be joined must be made. This is of considerable advantage, for example, in engine construction and in the automotive industry, because changes by as much as 0.1 mm usually require a complete overhaul of the corresponding component.

The surface of the metal substrate of the constructional element of the invention is preferably not more than 30%, and more preferably not less than 3%, coated with hard particles. According to a particularly preferred embodiment of the present invention, the coverage of the metal substrate with hard particles is between 5 and 15% of the total surface area coated with the friction-enhancing matrix.

However, it is also possible to incorporate into the binder phase and hard materials matrix further hard materials according to proven process patterns of the prior art.

This method variant is to be preferred if the construction element according to the invention, in addition to the properties described above, should have further special properties, in particular if the surface condition of the joining partner would require this.

According to a very particularly preferred embodiment of the present invention, the construction element has a cup shape. This embodiment has the particular advantage that the coating process of the base substrate with the dispersion layer of nickel and hard particles does not have to be carried out with a single clamping, but a coating of many construction elements in the drum process is possible, without here the otherwise observed deficiencies in terms of sufficient coating quality are watching. As a cup shape, all forms are here and hereinafter referred to have the component surfaces outside the arranged between the joining partners coated surfaces of the construction element according to the invention, in particular those which have the shape of a "cup", that surrounds the edges of at least one of the joining parts. These protruding from the plane of the joint surface component surfaces may be, for example, as flags or other edges or boundaries forming configurations. Such component surfaces are known per se, but have been used exclusively for easier reversible fixation on the workpiece to be joined, but not for the improvement of a more effective coating method without the otherwise known coating deficits in purchasing.

The present invention also relates to the use of the above-described construction element for friction-increasing play-free reversible connection of at least two workpieces to be joined, in particular for steering linkage or shaft / hub connections, very particularly preferably in automotive or engine construction.

In chemical NiP processes, very good bond strengths can be achieved on the substrate, which are for the most part better than in galvanic processes.

The highest possible increase in friction of the workpieces to be joined is given when the number of particles per unit area of the contact surfaces of the workpieces to be joined is selected so that the Joining the workpieces available normal force is sufficient to ensure an indentation of the particles in the mating surface without a "sinking" of the hard particles is observed in the metal substrate.

Thus, the best possible adhesion is given when the largest possible number of the particles located on the surface of the disc have completely or completely penetrated into the counterpart and the metallic binding phase is applied over its entire surface to the counter partner.

The following test tests were used to determine the friction-increasing properties and the tendency to fracture of the construction elements according to the invention:

Dynamic examination

• • schwellende Torsion mit 10⁷ Lastwechsel bei 80% des ermittelten Rutschmoments und danach Bestimmung des jeweiligen statischen Rutschmoments
• • schwellende Torsion mit 10⁷ Lastwechsel bei 80% des gemäß ermittelten Rutschmoments, Demontage der Verbindung, Wiedermontage der Verbindung, Belastung mit schwellender Torsion mit 107 Lastwechsel bei wiederum 80% des Rutschmoments und schließlich statisches Durchrutschen
• • Bestimmung des dynamischen Rutschmoment durch stufenweise Last Steigerung

The main focus of the investigations was on the dynamic experiments, using the design elements under investigation at a surface pressure of 100 MPa. Three different load variants were selected:

• • swelling torsion with 10 ⁷ load changes at 80% of the determined slip torque and thereafter determination of the respective static slip torque
• • swelling torsion with 10 ⁷ load changes at 80% of the determined slip torque, disassembly of the connection, reassembly of the connection, load with swelling torsion with 107 load changes again with 80% of the slipping torque and finally static slippage
• • Determination of the dynamic slip torque by incremental load increase

Each load variant was used with construction elements and construction elements according to the invention according to the EP 1 564 418 B1 using the material pairings 16MnCr5 / 16MnCr5 (case hardened). The strength of the surface of the case-hardened specimens (ie, the substrate of the workpieces to be joined in the sense of the present invention) is 840 N / mm ² .

The principle of the investigations, ie the load introduction in the torsion test, is shown in illustration 1. The design element to be examined is inserted between both test specimens. By the biasing force F _V , the desired surface pressure is generated on the disc. A torsional moment T _R is now introduced into the construction element to be examined.

As can already be deduced from the principle of load division, the two most important parameters are the preload force F _V and the torsional moment T _R. In addition, the recording of the angle of rotation is important in order to accurately detect the moment of slippage can.

To carry out the experiments, the torsion test rig was used with a force and wegtrollbaren hydraulic system. The linear movement of the hydraulic piston is converted by a lever in a rotational movement of the shaft. So that no transverse forces are introduced into the examined connection, a flexible coupling has been installed in front of the measuring shaft. The two cylindrical specimens are clamped in the torsion measuring shaft and in the transducer, as shown schematically in Figures 2 and 3, respectively. In between, the design element to be examined is inserted and the entire connection is axially preloaded with an M14 screw in accordance with the desired surface pressure. The power transmission between the coupling and the measuring shaft is realized in a form-fitting manner by a feather key connection. The same principle is then used in the derivation of the torque in the frame.

The biasing force F _V is measured by means of a 200 kN load cell. To determine the torque strain gauges were glued on the specially manufactured measuring shaft in the main stress directions at an angle of 45 °. As can be seen from illustration 3, the rotation between the test specimens of the test compound is determined by a lever by means of an inductive displacement sensor. For signal amplification and further processing is a multi-channel amplifier and a PC.

Experimental procedure:

Dynamic preload

The test program specifies a swelling torsion with 10 ⁷ load changes at 80% of the static slip torque during dynamic preloading. The static reference value (100%) was taken as the mean value from the static preliminary tests. The supplied test specimens are unpacked before the test from the protective paper and with the coated substrate touching functional surfaces with Degreaser cleaned. Then one of the test specimens is inserted into the measuring shaft and one into the transducer and clamped with a wedge and an M10 screw. Now the measuring shaft is installed in the test bench. On the preload screw, which is located in the transducer, the sleeve is tightened with a tested element and the compound assembled. The biasing force F _V is generated by means of an M14 screw and measured at the load cell. The desired surface pressure of 100 MPa corresponds to a preload force of FV = 31.4 kN. The test stand is now ready for the load. With the control of the servohydraulic system, the piston force pulsating at 35 Hz is adjusted so that the required swelling torsional moment corresponds to the setpoint. The measured quantities (preload force FV, torsional moment TR and torsion angle φ) are recorded every 180 seconds during dynamic preloading and the values are stored in the computer (periodic measurement). After 10 ⁷ load changes, the hydraulic system switches off automatically and the dynamic preload is over.

reassembly

In the test variant with reassembly the connection is dismantled after the dynamic preload. The preload screw is loosened and the test element removed, leaving the test specimens in the transducer or in the measuring shaft. The compound is then immediately reassembled and preloaded. Subsequently, a second dynamic load cycle is performed, which is identical to the first one (80% of the static slip torque, 10 ⁷ load changes).

Static slippage

After the specimens have been dynamically preloaded, the determination of the static slip torque follows.

The connection remains assembled after the preload, only the measurement technology is switched to a continuous measurement. All measured quantities are recorded in real time during the entire experiment with a sampling rate of 100 Hz.

From the unloaded state, the piston force of the hydraulic system is continuously increased. When reaching the turning limit, which is determined with a twist angle of 4 °, the hydraulic switches off, the connection is relieved and the experiment is completed.

From the recorded data, a torsional moment / torsion angle diagram (Figure 4) can be created during the evaluation, on which the course of the entire experiment is clearly observable. The moment of slipping can be clearly recognized by the marked maximum.

mit
T_R = Durchrutschmoment
F_V = Vorspannkraft
D_m = mittlerer Durchmesser der ringförmigen FlächenThe coefficient of friction μ is calculated from the slip torque and other variables as follows:

With
T _R = slip torque
F _V = preload force
D _m = mean diameter of the annular surfaces

Dynamic slipping

In the experiments with dynamic slipping, the installation of the test stand is carried out as already described on page 12. The measuring instruments are now set back to a periodic measurement, whereby the time between two measurements has been reduced to 5 seconds. This allows a good observation of the experiment and does not lead to a memory overload. The test starts with a swelling torsional load (35 Hz) which is far below the expected slip torque. In small steps, the mean momentum TRm and the momentum amplitude TRa are increased, so that the torque maximum TRo increases and the minimum TRu remains close to zero, as shown in FIG.

Between the load steps occur about 500 to 1,000 load changes. The experiment is aborted automatically after exceeding the Verdrehwinkelgrenze and terminated. From the measured values You can create two diagram types, Figure 6. The torsional moment-time diagram mainly shows the load increase. In the moment-twist angle diagram, however, slipping is very easy to read.

Examples - Coating:

To produce the connecting elements, initially annular disks (made from 1.4122) in the dimensions d 30/15 are punched out of an uncoated, correspondingly thick sheet of the material to be investigated.

The sheets to be hardened (from 1.4122) are cured in a hardening process at a temperature of 830 ° C, a holding time of 1 minute / mm and a quench in oil. The hardness is 64 HRC.

Subsequently, the hardened disc is subjected to a heat treatment at a temperature of 540 ° C and a holding time of 30 minutes and tempered to a tensile strength of 970 N / mm ² .

The fasteners are placed on a suitable brackets and degreased according to the described in the manual "The AHC Surface - Manual for Design and Manufacturing", 4th edition, Kerpen, Fa. AHC pretreatment process, pickled and activated.

Then, the discs are immersed in a mixture of a commercially available electroless nickel electrolyte, which is available under the name DNC 520 from the company. AHC, Kerpen, with 250 mg / l SiC (F600 from SaintGobain) dipped.

The pH of the electrolyte is adjusted with ammonia water 12.5% to the value 4.5-5.0, the temperature of the electrolyte is 85-90 ° C.

The deposition rate is 7-9 μm / hour, with the frame kept in motion during the coating process.

The electrolyte is circulated by a pump and kept in motion, so that located in the electrolyte hard particles can not settle on the bottom of the coating container. The dive time is 60 minutes. Then the support with the coated disks is removed from the electrolyte and cleaned in an ultrasonic bath to remove loosely adhering SiC particles.

The discs thus produced are examined by means of the previously described dynamic test with a preload of 100 MPa and a preload of 10 ⁷ load cycles

Comparative Example (not according to the invention):

According to the test series A no disc was placed between the test specimens.

Test Series B uses a 0.2 mm thick disc of the hardened material 1.4122 with a strength (yield strength) of 1,000 N / mm ² and an E modulus of 200,000 N / mm ² (corresponding to the EP 1 564 418 B1 ).

In the comparative experiments carried out no breakage occurred.

The results are shown in Table I as test series A to B.

Examples (coated according to the invention):

The experimental series 1 according to the invention uses a 0.2 mm thick aluminum alloy disk EN AW 7075 with a strength (yield strength) of 500 N / mm ² and a modulus of elasticity of 70,000 N / mm ² (corresponding to the EP 1 564 418 B1 ).

The test series 2 according to the invention uses a 0.2 mm thick sheet of the bronze alloy CuSn6 (2.1020) with a strength (yield strength) of 700 N / mm ² and an E modulus of 110,000 N / mm ² (corresponding to EP 1 564 418 B1 ).

Trial 3 uses a 0.3 mm thick sheet of non-hardened material 1.4301 with a strength (yield strength) of 700 N / mm ² and an E modulus of 200,000 N / mm ² .

In the experiments according to the invention carried out no breakage occurred.

The results are shown in Table 1 as test series 1 and 2.

Rating:

All slip curves show the same coefficient of friction characteristic with a pronounced transition adhesion-slip at about 0.3 ° relative displacement.

During the experiments with the friction discs EN AW 7075 The coefficients of friction of hardened discs made of 1.4122 according to the EP 1 564 418 B1 be achieved.

In the tests with the friction discs made of CuSn6, the friction coefficients of hardened discs made of 1.4122 according to the EP 1 564 418 B1 be improved.

Particularly noteworthy are the results with the stainless steel 1.4301 which far surpasses the values of the state of the art.

These results are surprising and unpredictable, since it was expected that the hard material particles in the - based on the strength of the workpieces to be joined 840 N / mm ² - softer substrate of the friction disk according to the invention (ie construction element with a strength of 500 or 700 N / mm ² ) and thus escape an increase in coefficient of friction in the form of microforming closures between the nickel layer protruding hard particles and the workpiece to be joined.

With the construction element according to the invention is the first time the prejudice according to the article "Friction-increasing surface layers for torsional stresses" by E. Leich, J. Lukschandel et al., Antriebstechnik (40), 2001, pp. 53-57 , of the EP 0 961 038 B1 and the EP 1 564 481 B1 refutes that the substrate of the friction disc must have a strength that is at least as high as that of the workpieces to be joined.

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

• DE 2364275 [0007]
• CH 192197 [0011]
• JP 6-147206 [0013]
• US 4525098 A [0015]
• US 4154276 A [0015]
• US 3828515 A [0015]
• US 3692341A [0015]
• DE 3149596 A1 [0017]
• DE 3237096 A1 [0019]
• DE 9402867 U1 [0020]
• EP 0961038 B1 [0023, 0025, 0026, 0029, 0030, 0039, 0098]
• EP 1564418 B1 [0029, 0030, 0039, 0061, 0085, 0088, 0089, 0094, 0095]
• EP 1564418 [0036]
• WO 2004/092436 A1 [0046]
• WO 2004/092256 A1 [0046]
• WO 2004/092445 A1 [0046]
• WO 2004/092444 A1 [0046]
• WO 2004/091906 A1 [0046]
• EP 1564481 B1 [0098]

Cited non-patent literature

• "Surface Layers for Non-positive Momentum Transfer" by H. Peeken, J. Lukschandel et al. in drive technology (20), 1981 [0007]
• "Friction-enhancing surface layers for torsional stresses" by E. Leidich, J. Lukschandel et al., Antriebstechnik (40), 2001, pp. 53-57 [0026]
• Peeken, Lukschandel and Paulick, "Surface Layers for Non-Positive Momentum Transfer", in "Ant Drive Technology, January / February 1981" [0032]
• E. Leidich, J. Lukschandel et al. [0033]
• EN AW 7075 [0088]
• EN AW 7075 [0094]
• "Friction-increasing surface layers for torsional stresses" by E. Leiku, J. Lukschandel et al., Antriebstechnik (40), 2001, pp. 53-57 [0098]

Claims (14)

Construction element for friction-enhancing play-free reversible connection of workpieces to be joined, consisting of a substrate having on its surface hard material particles of defined size, wherein the hard material particles are fixed by means of a metallic binder phase of a chemically deposited nickel / phosphorus alloy on the substrate, characterized in that the Substrate has an intrinsic strength which is lower than that of the workpieces to be joined. Construction element according to claim 1, characterized in that the substrate is a metal substrate made of a light metal or its alloys, aluminum, an aluminum alloy or a stainless steel alloy. Construction element according to claim 2, characterized in that the metal substrate is made of a copper-containing aluminum alloy, in particular the alloy AlSiCu 1.5 (7050) or AlZnMgCu1.5 (7075) ENAW7075, AlZn4.5Mg1 (7020) 3.445 AW7020, AlCU4Mg1 (2024) ENAW2024 or X5CrNiMo1808 (4301). Construction element according to claim 1, characterized in that the substrate is a polyester-bonded thermoset, on which a metal layer is applied. Construction element according to claim 1, characterized in that the substrate is a metal substrate of a brass or bronze alloy. Construction element according to one of the preceding claims, characterized in that the hard material particles are selected from the group consisting of diamond, silicon carbide or tetraborcarbide. Construction element according to one of the preceding claims, characterized in that the hard material particles have a diameter of not more than 19 microns. Construction element according to one of the preceding claims, characterized in that the metal substrate has a thickness of less than 0.5 mm, in particular less than 0.2 mm. Construction element according to one of the preceding claims, characterized in that not more than 30% and not less than 3% of the surface of the metal substrate is coated with hard material particles Construction element according to one of the preceding claims, characterized in that the hard material particles cover 5 to 15% of the metal substrate. Construction element according to one of the preceding claims, characterized in that the construction element has a cup shape. Use of a construction element according to one of the preceding claims for the friction-enhancing play-free reversible connection of at least two workpieces to be joined. Use according to claim 12 in a steering linkage, in particular in the automotive industry. Use according to claim 12 in a shaft / hub connection, in particular in engine construction.

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