EP4351802A1 - Joint présentant de bonnes propriétés anti-friction, son utilisation et son procédé de production - Google Patents

Joint présentant de bonnes propriétés anti-friction, son utilisation et son procédé de production

Info

Publication number
EP4351802A1
EP4351802A1 EP22732212.0A EP22732212A EP4351802A1 EP 4351802 A1 EP4351802 A1 EP 4351802A1 EP 22732212 A EP22732212 A EP 22732212A EP 4351802 A1 EP4351802 A1 EP 4351802A1
Authority
EP
European Patent Office
Prior art keywords
sealing ring
coating
sealing
radius
ring according
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.)
Pending
Application number
EP22732212.0A
Other languages
German (de)
English (en)
Inventor
Dominik PAULKOWSKI
Ralph Wilken
Klaus-Dieter Vissing
Farkhod BABADJANOV
Igor QUIRING
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.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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 Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of EP4351802A1 publication Critical patent/EP4351802A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/62—Plasma-deposition of organic layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/002—Pretreatement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/08—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/02—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to macromolecular substances, e.g. rubber
    • B05D7/04—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to macromolecular substances, e.g. rubber to surfaces of films or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2350/00—Pretreatment of the substrate
    • B05D2350/30—Change of the surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2350/00—Pretreatment of the substrate
    • B05D2350/30—Change of the surface
    • B05D2350/33—Roughening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2350/00—Pretreatment of the substrate
    • B05D2350/30—Change of the surface
    • B05D2350/33—Roughening
    • B05D2350/38—Roughening by mechanical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/14—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by electrical means
    • B05D3/141—Plasma treatment
    • B05D3/142—Pretreatment
    • B05D3/144—Pretreatment of polymeric substrates

Definitions

  • the invention relates to a sealing ring made of elastomeric material for dynamic loads, the sealing ring being doubly curved in the area of the contact zone and certain specifications applying to the curvature, with at least 50% of the contact width of the contact zone being provided with a wear-reducing plasma polymer coating or a bonded coating .
  • the invention also relates to the use of a corresponding sealing ring and a method for its production.
  • US 2013187342 A / WO 2011/110360 A1 describes a radial shaft seal made of elastomer with microstructures in the area of the contact surface between the seal and the running surface.
  • it describes the size, density and depth of the structures, in particular cups as indentations, e.g. cylindrical, conical or truncated.
  • a high contact area of 70% to 90% is required in order to ensure tightness in contact and possibly also wear resistance.
  • Wear-resistant coating can be applied to the contact surface to further improve wear resistance.
  • This document discloses a contact width of up to 1mm.
  • the German Patent and Trademark Office has also identified the following prior art for the priority application DE 102021114904.5: DE 102009027768 A1, DE 102008002515 A1, DE 102009046947 A1 and DE 4018278 A1.
  • US 2013187342 A / WO 2011/110360 A1 does not describe how a microstructured sealing lip must be shaped in order to be able to ensure long-term stability over the service life and wear resistance, particularly in the contact zone. For this purpose, the wear resistance of the coating on the respective substrate material would have to be ensured.
  • the object of the present invention to specify a sealing ring that has a special range of properties from friction values and wear values and at the same time is able to ensure its sealing function over a long period of time.
  • the object of the invention should be to specify seals that have a sufficient service life so that they can guarantee a service life of 200,000 km for a car, for example, without losing their function.
  • SA Shore hardness A of the elastomeric material (without units), with at least 50% of the contact width of the contact zone being provided with a wear-reducing plasma polymer coating or an anti-friction varnish.
  • a sealing ring in the sense of the present invention is to be understood as meaning an annular material intended for sealing purposes, which does not necessarily have to have a circular shape, although a circular shape is preferred. Other shapes can be oval or even approximately polygonal, for example.
  • a recess is preferably provided in the middle of the sealing ring, which is intended to accommodate one of the two bodies to be sealed off from one another.
  • a sealing ring within the meaning of the present invention cannot be closed either, i.e. in this special case segments of a sealing ring are also to be understood as a sealing ring or--even if only preferred under certain circumstances--wiper blades, e.g. for windshield wipers.
  • a sealing ring for dynamic loading within the meaning of the present invention is a sealing ring that is intended to seal sealing points with relative movement of two bodies (seal and counter-body).
  • the stationary parts of a motor can be one body and the counter-body a rotating shaft.
  • many other configurations for the counter-body are also possible, such as translatory rods for rod seals or glass panes for wiper blades. In the sense of the present definition, it is not necessary for one of the two bodies to be stationary. It is also conceivable that both bodies that are to be sealed off from one another are moved.
  • the sealing ring has the “contact zone” which bears against one of the two bodies that is moved relative to the seal, with this body preferably being the counter-body that is in contact with the sealing ring and is usually surrounded.
  • the area of the sealing ring that carries the contact zone is also referred to as the "sealing lip".
  • a sealing lip within the meaning of the present invention has at least one, but can also have several contact points or even sealing edges.
  • the minimum sealing edge radius n is the minimum radius of curvature in the contact zone.
  • the decisive factor for determining the sealing edge radius n is the minimum radius of curvature in the contact zone. It is preferred that the position of the minimum radius n of the sealing ring is shifted towards the oil side by the combination of several radii of curvature and possibly straight lines compared to the center of the contact width.
  • Radius G2 is the inner radius of the sealing ring. Unless the sealing ring is of circular construction as defined above, G2 is the radius of the largest possible circle in the area of the sealing ring recess that can be laid without cutting the sealing ring. If the sealing ring is not closed, radius G2 is the minimum radius of curvature of the sealing ring segment.
  • ⁇ for the ratio r2/n means that r2/n is at least 10, preferably at least 20, more preferably at least 50, even more preferably at least 100 and particularly preferably at least 200.
  • the contact width within the meaning of the present invention is determined as in measurement example 1.
  • the measurement example determines the "mean contact width". Accordingly, the wording that at least “50% of the contact width of the contact zone is provided with a plasma polymer coating or a bonded coating” means that 50% of the (surface) area (of the contact zone) defined by the average contact width is coated accordingly. It is not necessary for the coating to be continuous and/or regular along the inner circumference of the sealing ring, but it is preferred within the meaning of the present invention to provide a circumferential coating that is constant in terms of its width along the circumference.
  • Preferred elastomers are ACM, HT-ACM, AEM, BR, CR, ECO, EPDM, FKM, FFKM, FKM-P, IIR, IR, NBR, HNBR, NR, SBR, Therban, as well as silicone, VMQ and TPE.
  • the surface of the contact area of the sealing lip must be double-curved with the radii n and G2, where the following applies : No. 2
  • the radius G2 is determined by the subsequent application and is typically somewhat smaller than the radius of the shaft to be sealed rw (counterbody), particularly in the case of radial shaft seals. Typically 0.8 ⁇ r2/rw ⁇ 1.0 applies here
  • the coefficient r2/rw is preferably selected to be small for elastomers with a low Shore A hardness and large for elastomers with a high Shore A hardness.
  • the sealing lip profile in the area of the subsequent contact zone does not have to be circular, but can also be hyperbolic, elliptical or oval in shape for gentler force distribution in the sealing area.
  • the sealing lip profile can also have different radii on the air or oil side.
  • the radius n describes the largest curvature / smallest radius of curvature in the sealing area.
  • the radius n must be adapted to the mechanical properties of the anti-wear coating, the elastic properties of the elastomer and the required ring tension (which is caused when the radial shaft seal is pushed onto the shaft and the deformation of the sealing lip).
  • the radius n must not be too large in order to still ensure adequate tightness, particularly when there is a contact area with a microstructure (see below).
  • the minimum sealing edge radius n is determined according to measurement example 5. This selection of the correct radius of curvature n in the area of subsequent two-body contact makes it possible to permanently use structuring that even has a surface area of ⁇ 70%.
  • a plasma polymeric coating within the meaning of the present application is a coating that was produced or can be produced by plasma-enhanced chemical vapor deposition (PECVD).
  • PECVD plasma-enhanced chemical vapor deposition
  • a bonded coating within the meaning of the present invention is a one-component or multi-component coating whose effect is to reduce friction and wear.
  • a matrix of binder and dry lubricant is often used under this name.
  • binders such as PUR, acrylic or resin are used in combination with lubricants such as PTFE, talc, PA, silicone oil or graphite. Silicone resin, ceramics, xanthan or bentonite are also used.
  • a bonded coating is understood to be a coating with a layer thickness ⁇ 100 ⁇ m and a coefficient of friction ⁇ 0.35 determined according to measurement example 9.
  • the configuration of the sealing ring according to the invention in particular taking into account the radius n according to the formula given above, leads to a significant improvement in the properties of a sealing ring.
  • corresponding sealing rings prove to be particularly durable, especially in terms of wear resistance, while they still have good sliding properties.
  • the difference to sealing rings with a serrated edge can be seen as an improvement.
  • a sealing ring according to the invention with the following properties is preferred:
  • the angle of attack of the flanks for the sealing contact is 15-70° at the front and/or 10-60° at the bottom, preferably 40-50° at the front and/or 20-30° at the bottom (alternatively preferably 30-45° at the front and bottom).
  • Front means oil side
  • bottom means air side (dry).
  • the asymmetrical angle of attack of the flanks results in an asymmetrical force distribution in the contact area (the contact zone), which is advantageous for the tightness of the seal and for the return of the lubricating medium.
  • the sealing edge radius n is preferably based on the Shore hardness of the elastomer and the contact pressure. The contact pressure and the system pressure are decisive for the tightness. With a sufficient, critical pressure of 2 MPa, depending on the Shore hardness and line pressure of the seal, there are different preferred radii of the sealing lip (cf. FIG. 1 sealing edge radius vs. Shore hardness).
  • Figure 1 shows the dependence of the minimum radius n as a function of the Shore A hardness for preferred values in order to obtain a compression of 2 MPa with a given applied force/sealing length of 0.15 N/mm (such a compression represents ensure tightness).
  • FIG. 2 shows the diagram of the preferred sealing edge radius in pm for the given contact width 2a in pm.
  • the line pressure within the meaning of the present invention is the radial force related to the circumference in N/mm. In particular, it serves to facilitate the comparability of systems of different sizes.
  • the Shore A hardness is determined according to measurement example 4.
  • n k1/(111 -SA) 2 with
  • the minimum radius of curvature n starting from the minimum sealing ring radius G2, is particularly preferably on the end face side.
  • the contact zone is provided with a wear-resistant coating:
  • Bonded coatings At least part of the structure width and depth are covered by bonded coatings, preferably 5-15 ⁇ m thick. In addition, the bonded coatings are smeared in their functionality, which clogs the structures (in the case without microstructures)
  • Plasma coatings thickness 0.2-5 ⁇ m, preferably 1-4 ⁇ m. These coatings can show cracks (because they are stiffer than elastomers) at the latest after the elastomer has been subjected to tensile or compressive loads (when the seal is used).
  • At least 50% of the contact width of the sealing ring contact zone is coated with a friction-reducing coating to ensure good wear resistance and friction properties.
  • the flanks of the sealing lip are preferably also (at least partially) coated.
  • a sealing ring according to the invention is preferred, wherein the sealing ring is/are microstructured in particular in the area of the contact zone and/or the flanks of the sealing lip.
  • Microstructures are depressions (valleys) or elevations (peaks) whose maximum depth or maximum height is at least 5 times greater, preferably 10 times greater than the roughness R z of the sample measured in an area without a microstructure.
  • the histogram of the roughness peak heights related to the baseline is evaluated to separate roughness and microstructure.
  • the proportion of the area of the microstructures results from the area of the microstructures, which are recorded from the direction of the surface normal in relation to the analysis area.
  • the analysis area must be at least 20 times the area of a microstructure.
  • a sealing ring according to the invention is preferred in which the microstructured surface has a surface area of ⁇ 60%.
  • the surface area of the microstructures with indentations (valleys) is preferably 2-60%, preferably 5-40%, more preferably 10-35%, more preferably 20-30%.
  • the proportion of the surface of the microstructures with elevations is preferably 5-50%, preferably 10-50%, more preferably 20-50%, more preferably 30-50%.
  • a sealing ring according to the invention is preferred in which the degree of coverage >20%, preferably >50% of the contact zone is microstructured.
  • the contact zone is microstructured.
  • This of course presupposes that there is also a corresponding surface that can carry the corresponding microstructures.
  • the entire contact area is provided with a wear-reducing plasma polymer coating or a lubricating varnish and is also completely microstructured in the sense of the above definition.
  • a sealing ring is preferred according to the invention, the coating preferably being plasma polymer and having a layer thickness of 0.2-5 ⁇ m.
  • the plasma polymeric layer is a gradient layer:
  • the elastic properties of the layer have a gradient, starting from the elastomer with low moduli of elasticity towards higher moduli of elasticity with greater layer thicknesses.
  • the modulus of elasticity increases with increasing network density and decreases with increasing hydrogen content.
  • the elastic properties or the hardness of the layer can be adjusted by adjusting the carbon content and the network density will.
  • the deposition parameters can be adjusted accordingly: the modulus of elasticity increases with an increasing proportion of sp3 hybridization of the carbon, and the modulus of elasticity decreases with increasing hydrogen content.
  • the modulus of elasticity and hardness can be continuously increased.
  • a seal according to the invention is preferred in which the coating has a roughness value R a of 0.2-1.5 ⁇ m and/or a roughness value R z of 1.0-4.0 ⁇ m.
  • the roughness value is determined according to measurement example 2.
  • the roughness is preferably the root mean square of the gradient Sdq 0.04-0.50, preferably 0.10-0.45, more preferably 0.2-0.42, the root mean square also being determined according to measurement example 2 in cases of doubt.
  • a sealing ring according to the invention is preferred, the coating having a modulus of elasticity of 0.2-140 GPa and/or a surface energy of 20-45 mN/m and/or a static contact angle to n-decane of ⁇ 10°.
  • the modulus of elasticity is preferably 20-90 GPa, more preferably 35-90 GPa (the latter value in particular for DLC layers) and alternatively preferably 0.2-70 GPa (the latter value for SiOx plasma polymer layers), further alternatively preferably 30-65 GPa .
  • the modulus of elasticity is determined according to measurement example 6.
  • the surface energy of the wear-reducing coating to be used according to the invention is preferably 24-45 N/mm, more preferably 28-42 N/mm and is determined according to measurement example 7 in case of doubt.
  • the contact angle with respect to n-decane is determined according to measurement example 8.
  • a sealing ring according to the invention is preferred, the flanks of the sealing ring also being at least partially provided with the plasma polymer coating.
  • the wear-reducing coating to be used according to the invention is a plasma polymeric coating based on HMDSO (SiO x C y H z , preferably in chemical compositions as disclosed in EP 2 291 439 A1, sealing article) or a DLC -layer is. Accordingly, a seal according to the invention is preferred, the plasma polymeric coating on the elastomer having a composition of
  • O 20-26 at% in each case based on the amount of all atoms measured with XPS, except in the case of H, where it is determined by means of microelement analysis and where H is not included in the proportions of elements detectable with XPS, or where the plasma polymeric coating has a C /H ratio is between 1.9 ⁇ C/H ⁇ 2.8, preferably 2.1 ⁇ C/H ⁇ 2.6, determined by means of microelement analysis, and has a Si content of ⁇ 10 at%, preferably ⁇ 5 at%, based on the set of all atoms measured by XPS, and where H is not included in the proportions of elements detectable by XPS.
  • the coating preferably also acts as a friction-reducing layer.
  • a layer that reduces the real contact area compared to the uncoated case is preferred. This is achieved, for example, by the values given above for the increased square mean of the slope in the topography compared to the uncoated case and an increased modulus of elasticity.
  • the person skilled in the art takes suitable precautions to ensure the adhesion of the layer. This includes a suitable choice of elastomer and a suitable cleaning of the elastomer before coating, e.g.
  • wet-chemical cleaning aqueous or solvent-based
  • dry-physical cleaning such as laser cleaning, plasma cleaning, cleaning using high-energy UV radiation, in particular VUV radiation, cleaning using CO2 (CO2 snow jet cleaning, dry ice blasting), grinding, particle blasting.
  • Activation of the elastomer surface can also be helpful to ensure layer adhesion.
  • Chemical activators, adhesion promoters, plasma-based activation (LP plasma, AD plasma, laser), VUV radiation, flame treatment are possible for this.
  • adhesion promoter for the transition to the actual functional layer.
  • the person skilled in the art will ensure that the adhesion promoter, particularly in the case of organosilicon layers, is in the form of a gradient and that the gradient makes up no more than 25%, preferably 15%, more preferably 10% of the total layer thickness.
  • At least the contact zone is preferably coated. This is preferably determined by the desired line voltage: low line voltage, resulting in a small contact width or high line voltage, resulting in a large contact width.
  • Preferred (average) contact widths are between 25 and 200 ⁇ m, more preferably between 60 and 150 ⁇ m.
  • good wetting properties are set in the contact zone and poor wetting properties are set outside of the contact zone.
  • This can be achieved by either only giving the area of the contact width a hydrophilic coating (using masks) (if the elastomer already has hydrophobic, better oleophobic properties) or by additionally providing the area of the flanks with a hydrophobic/oleophobic coating. More preferably, only the area of the flanks on the air side is made hydrophobic/oleophobic. The effect of this is that better oil lubrication is made possible and oil return (no oil wetting of the air-side flank) is achieved.
  • the adjustment of the roundness n of the sealing lip and microstructure in one step is particularly preferred.
  • the sealing rings whose flank geometry is defined by the shaping during vulcanization, are formed with a suitable rounding and microstructure in the area of the sealing lip.
  • preference is given to adjusting the roundness n of the sealing lip by sliding the sealing ring according to the invention over a shaft with abrasive structures, eg sandpaper, using pierced tools according to the prior art, and turning it.
  • the shaft already has the dimensions of the shaft in later use.
  • the compression or injection burrs of the elastomer in the area of the sealing lip are removed and a geometry is established that does not have any peaks in the force curve over the contact width.
  • the adjustment of the roundness n of the sealing lip by sliding the sealing ring according to the invention over a shaft without abrasive structures and turning it with a pierced device according to the prior art.
  • the shaft already has the dimensions of the shaft in later use.
  • the pierced edge of the elastomer in the area of the sealing lip is rounded off by the running-in of the sealing ring.
  • a sealing ring according to the invention is preferred, the elastomeric material having a Shore A hardness of 30-90. More preferred shore hardnesses are described further below.
  • the sealing ring according to the invention is preferably provided with the following microstructures, particularly in the area of the contact zone:
  • the width of the structures depends on their depth. With a depth or height of 1-10 ⁇ m, the width should not exceed 1:10 (e.g. triangles) or 1:5 (“ovals”/rectangles with attached semicircles on the short sides) or 1:3.75 (e.g. knobs/cells). . The width at 5-50 pm depth or height should not exceed 1:3 (double lips).
  • Shore hardness 60-90 Shore A: structure depth or structure height 1 to 50 ⁇ m, particularly preferably 1 to 35 ⁇ m
  • Shore hardness 20-60 Shore A: Structure depth or structure height 1 to 50 ⁇ m, especially 5 to 50 ⁇ m
  • depressions preferably 2-60%, preferably 5-40%, more preferably 10-35%, more preferably 20-30%
  • o Triangles preferably isosceles triangles, with a depth of 0.5 to 50 ⁇ m, preferably 10 to 0.5 ⁇ m, preferably 2 to 1 ⁇ m, preferably 1.7 to 1.3 ⁇ m pm depth at deepest point; and a width of 175 to 5 pm, preferably 50 to 5 pm, preferably 20 to 5 pm, preferably 18 to 13 pm, preferably 16 to 14 pm and a length of 40 to 10 pm, preferably 35 to 25 pm, preferably 32 to 28pm; wherein the depth increases from the long side as well as the wide ends, the long side tapers out shallower, the long side is aligned in the circumferential direction of the shaft; o “Ovals” (rectangles with attached semicircles on the short sides) with a depth of 15 to 2 ⁇ m, preferably 13 to 5 ⁇ m, preferably 10 to 6 ⁇ m; with a width of 50 to 20 pm, preferably 45 to 35 pm, preferably 42 to 38 pm and a length
  • Circumferential grooves wherein the waveform of the pits relates to the Gaussian cross-sectional track caused by the laser; with a depth of 20 to 1 pm, preferably 15 to 5 pm, preferably 12 to 8 pm, with a width of 50 to 10 pm, preferably 50 to 20 pm, preferably 45 to 30 pm, preferably 42 to 38 pm.
  • cell structures as described in WO 2011/110360 A1 are also preferred as an alternative.
  • a contact area of the surface ⁇ 70% when using the structures described is particularly preferred.
  • a contact percentage of 50 to 70% is particularly preferred. Due to the coatings described above, such small contact areas are also possible for long-term applications.
  • both elevations and depressions in the elastomer can be produced either by surface treatment of the elastomer after shaping (e.g. by laser, grinding, drilling, blasting) or during shaping using a suitable mold. Indentations must be made in the mold for elevations in the elastomer. Accordingly, the depressions in the elastomer can only be realized via elevations in the mold. A laser is preferably used for this purpose. For indentations (in the elastomer) with larger diameters or depths, this means a considerable amount of time for structuring (the shape).
  • the elevations required for the depressions in the elastomer can also be produced using additive manufacturing processes such as laser sintering or build-up welding.
  • Part of the invention is also a method for producing a sealing ring according to the invention, comprising the steps a) providing an uncoated sealing ring made of elastomeric material, preferably as defined above b) forming a double curvature in the area of the contact zone as defined above. c) Coating with a plasma polymeric coating as defined above.
  • sealing rings according to the invention can be produced in this method, with the person skilled in the art already having received a large number of references to the configuration of the method in the text above.
  • step b.) already takes place during the production of the actual sealing ring (primary forming).
  • Measurement example 1 determination of the mean contact width ⁇ b>
  • the (dynamic) seal is pushed onto the shaft provided for this purpose.
  • the shaft is then coated with >20 ⁇ m of a paint, preferably a spray paint containing solvent, so that the seal is sprayed with paint on both sides.
  • 10 sections are made parallel to the axis of rotation of the shaft and perpendicular to the tangent.
  • the mean contact width ⁇ b> is the arithmetic mean of the 10 measured contact widths bi to bio.
  • Measurement example 2 Determination of the roughness values R a , Rz and Sd q : A sample is prepared from a seal as follows:
  • a cut is made parallel to the rotational symmetry axis of the seal and perpendicular so that the cut elastomer has a minimum thickness of ⁇ 500 pm.
  • a sample with a length of 5 mm is cut out symmetrically at the point of minimum thickness.
  • the topography is determined using an atomic force microscope (AFM: EasyScan2, from NanoSurf) in a scanning field of 90 ⁇ 90 ⁇ m. The sample was positioned under the gauge needle with the airside flank up. The scan takes place line by line on this horizontally arranged edge. For easier tracking during the measurement, a line is measured along the circumferential direction of the seal (here the longer dimension 5 mm).
  • the roughness parameters R a and R z were determined based on DIN 4287 by placing and evaluating 5 lines in the abscissa direction and ordinate direction of the measuring field.
  • the evaluation software Digital Surf/Mountain Software Version 6.2.7487 was used.
  • the mean square gradient of the surface Sdq of the AFM measuring field mentioned above is determined based on ISO 25178.
  • the evaluation software Digital Surf/Mountain Software Version 6.2.6409 was used.
  • Measurement example 3 Test bench RWDR run-in and component tests A universal material tester (UMT3, Bruker, formerly CETR) is used for run-in and later friction torque measurements.
  • a rotating drive (S33HE), a force sensor (DFH-20) and a torque sensor (TH-25) are assembled as components.
  • a stub shaft (035 mm) with a cone on the underside is installed in a rotating drive (S33HE) for centering. The upper end of the stub shaft is rounded (radius 2 mm).
  • the test item in the form of a radial shaft seal ring (RWDR) of a suitable size for the shaft sits in a recess in a rotationally symmetrical holder.
  • a housing cover with a recess for the shaft fixes the test item in the installation space.
  • a ball bearing with a central pin is located in the middle of the bracket. This pin is inserted centrally from above into the stub shaft as a bearing.
  • the stub shaft is rotated at 60 rpm. Mating forces are observed using the DFH-20 strain gauge sensor.
  • the RWDR is plugged on dry under normal ambient conditions.
  • insertion forces of less than 10 N occur.
  • the shaft rotates dry at 200 rpm.
  • the duration depends on the desired sealing edge radius.
  • the fitting is carried out in the same way as the running-in process. The component test is carried out for 100 s at 1000 rpm.
  • Measurement example 4 Description of Shore A test with hand-held device
  • the Shore A hardness is measured using a hand-held device (HP-Shore A) from Bareiss based on DIN ISO 7619.
  • the measuring needle is placed on a section of the sealing lip that has been cut out and pressed in up to the base plate.
  • a measurement on a rubberized section of the stiffening ring can lead to an incorrect assessment due to the insufficient thickness of the elastomer.
  • Measurement example 5 Minimum sealing edge radius n:
  • a sample is prepared from a seal as follows:
  • a cut is made parallel to the axis of rotational symmetry of the seal and perpendicular to it so that the cut elastomer has a minimum thickness of 3 mm.
  • a sample with a length of 5 mm is cut out symmetrically at the point of minimum thickness.
  • This sample is divided in the middle so that the cut is parallel to the surface normal of the first cut and parallel to the axis of rotational symmetry of the seal, so that the cut surface of the second cut gives the profile of the sealing lip.
  • the sealing lip profile is determined using light microscopy. Two points (X) 500 ⁇ m and 1.0 mm to the left of the narrowest cross-section of the sealing ring are marked on the sealing lip profile and connected with a straight line. It will be on the sealing lip profile marked two points (X) 500 ⁇ m and 1.0 mm to the right of the narrowest cross-section of the sealing ring and connected them with a straight line.
  • FIG. 3 The reference symbols 1 mean: point on sealing lip profile 2: sealing lip profile
  • the angle g (in degrees) spanned by these two straight lines is determined.
  • the radius n is calculated as follows:
  • the radius n can be determined according to the definition even if there are different curvatures in the area of the contact zone/of the sealing lip profile.
  • Measurement example 6 hardness and modulus of elasticity of the coating
  • Nanoindentation is a testing technique that can be used to determine the hardness of surface coatings using a fine diamond tip (three-sided pyramid [Berkovich], radius a few 100 nm).
  • the remaining indentation trough imprinted by a normal force is not measured, but a penetration depth-dependent cross-sectional area of the nanoindentor is assumed. This depth-dependent cross-sectional area is determined using a reference sample with a known hardness (usually high-purity quartz glass).
  • a Universal Material Tester (UMT1) from Bruker with a NanoHead (NH-2) is used to measure the hardness and modulus of elasticity of the coating.
  • nanoindentation uses a sensitive deflection sensor (capacitive plates) with which the penetration depth can be precisely measured as the normal force increases and decreases again - quite differently from the classic procedure -.
  • the normal force versus indentation depth curve indicates the in situ stiffness of the specimen during the initial phase of unloading.
  • the modulus of elasticity and the hardness of the sample can be determined using the cross-sectional area of the nanoindentor known from the reference sample.
  • the maximum test force for nanoindentation is usually below 15 mN.
  • a rule of thumb of 10% of the coating thickness is used to measure the pure properties of the coating without being influenced by the substrate. Deeper penetration curves include an influence of the substrate used. With increasing penetration depths of more than 10% of the layer thickness, the measured values for modulus of elasticity and hardness gradually approach those of the substrate. The evaluation described using this measurement method is named after Oliver & Pharrl. Coated Si wafers were nanoindented to avoid the effect of the very flexible elastomer substrate.
  • the so-called multiple loading and unloading method is used to make it easier to vary the indentation depths for different loads.
  • debits and credits are made segment by segment at a fixed point.
  • the local maximum loads are continuously increased.
  • depth-dependent values of the modulus of elasticity and hardness can be determined at the fixed point.
  • various unaffected points on the sample are also approached and tested on a measuring field.
  • the maximum force for the penetration depth and the corresponding relief curve is therefore preferably ⁇ 1 mN, more preferably ⁇ 0.055 mN; depending on a layer thickness of ⁇ 1 ⁇ m, it is more preferably ⁇ 0.020 mN.
  • Measurement example 7 surface energy The free surface energy for solids is measured indirectly via the contact angle. Various methods exist for calculating the surface free energy from the contact angle. It is evaluated according to the Owens-Wendt-Kaelble-Rabel method 3 ' 4 ' 5
  • n-decane is used here as a model oil.
  • the spread of such an oil drop ⁇ 10° should already indicate this.
  • the application is carried out as described in measurement example 7, using n-decane as the test liquid.
  • Measurement example 9 Friction measurement in ball-plane contact To determine the friction of a coating or bonded coatings on elastomer material, a coated resp. Painted elastomer plate glued on and mounted on a guide carriage. A 100Cr6 (010mm) bullet is used as a counter body. This ball is fixed in a holder in such a way that it can be guided over the sample without rolling. The guide carriage moves in an oscillating manner at 200 mm/s and a stroke of 11 mm. A Universal Material Tester (UMT3, Bruker) was used to carry out the test. The normal force can be set using a force sensor (DFH-20) and the lateral force can be measured as friction force. The normal force applied is 15 N.
  • the coefficient of friction is calculated as the quotient of the friction force divided by the normal force.
  • the ambient conditions are normal.
  • the selected normal force of 15 N corresponds to an initial Hertzian surface pressure of approx. 2.6 MPa for materials and geometries in contact (steel ball with 195 GPa modulus of elasticity against elastomer plate with 75 Shore A hardness, converted 6 9.4 MPa modulus of elasticity).
  • This is a common size for an application such as a radial shaft seal.
  • the oscillating movement represents an extraordinarily high load for the sample. With the flexing work in the solid and a constant load at the reversal points, samples wear out very quickly in this test arrangement.
  • FIG. 4 shows the measuring setup in the form of a sketch, with the reference symbols having the same meaning
  • Exemplary embodiment 1 (not according to the invention)
  • RWDR radial shaft sealing ring
  • a shaft with a diameter of 35 mm with a pierced sealing lip (Shore-A hardness 72, material elastomer NBR, standard design A according to DIN 3760, (BAU3X2 35, 0X 5, NBR902 from Freudenberg Sealing Technologies)) was analogous to Example 3 from WO09153306 A1 coated:
  • the RWDR were pre-cleaned using aqueous cleaning in an ultrasonic bath at 60 °C.
  • An adherent plasma polymeric coating resulted with a layer thickness of about 1.5 ⁇ m on the sealing edge.
  • the modulus of elasticity was 50.10 ⁇ 4.13 GPa. This was measured on a Si wafer which, during coating, rested on its sealing edges in a stack with separate RWDRs (open on both sides). The surface energy was 43.95 ⁇ 0.5 mN/m on a glass slide outside the stack 20 cm from the RWDRs. The radius was determined according to measurement example 5 and was 10 ⁇ m.
  • the roughness values on the sealing edge were R a 0.55 ⁇ 0.16 pm, R z 2.74 ⁇ 0.87 pm and Sdq 2.77 ⁇ 0.20.
  • This RWDR was tested on the test stand (as in measurement example 3) for long-term stability.
  • the RWDR was placed on the designated repair sleeve on a shaft with a diameter of 35 mm and tested for 100 s at a rotational speed of 1000 rpm without using any oil. After 100 s, the measured torque was 0.63 ⁇ 0.01 Nm.
  • the sealing lip was analyzed and analyzed using electron microscopy and energy dispersive X-ray fluorescence. The coating was rubbed away over an area of approx. 100 ⁇ m.
  • Embodiment 2 (according to the invention)
  • This RWDR was run in dry on the test stand (as in measurement example 3).
  • the RWDR was placed on the designated repair sleeve on a shaft with a diameter of 35 mm and rotated at a constant rotational speed without using any oil.
  • the radius was reproducible with a break-in period of 1 hour at 200 rpm.
  • the radius was determined according to measurement example 5 and was 141 +/-12 pm.
  • the radial shaft sealing ring obtained in this way was coated and tested analogously to exemplary embodiment 1. Modulus of elasticity and surface energy apply accordingly.
  • the roughness values on the sealing edge were R a 0.44 ⁇ 0.20 pm, R z 1.98 ⁇ 0.69 pm and Sdq 2.10 ⁇ 0.17.
  • the sealing lip was analyzed analogously to exemplary embodiment 1 and analyzed by means of electron microscopy and energy-dispersive X-ray fluorescence.
  • the coating could be detected in the entire area. Only cracks that led to a lump-like coating could be observed.
  • Embodiment 3 (according to the invention)
  • a RWDR from Example 1 with a pierced sealing lip (Shore-A hardness 72, material elastomer NBR, standard type A according to DIN 3760 (BAU3X2 35, 0X 5, NBR902 from Freudenberg Sealing Technologies)) was pretreated before coating as follows: First, a Dry run-in according to measurement example 3 analogous to example 2. The radius was determined according to measurement example 5 and is 141 +/- 12 ⁇ m. In the area of the contact zone and adjacent flanks, a laser treatment was carried out with the following parameters:
  • YLPF-10-500-10-R IPG company
  • 2D scanner ARGES Compact Scan Head “Fiber Rhino 16”
  • Sample screening was done in point mode. Cells with a diameter of 100 ⁇ m and a depth of 50 ⁇ m and a rotationally symmetrical, Gaussian depth profile are obtained.
  • the bearing percentage was 45 ⁇ 2%
  • the radial shaft sealing ring obtained in this way was coated and tested analogously to exemplary embodiment 1. Modulus of elasticity and surface energy apply accordingly. Without microstructuring, the roughness values on the sealing edge were R a 0.44 ⁇ 0.20 pm, R z 1.98 ⁇ 0.69 pm and Sdq 2.10 ⁇ 0.17.
  • the sealing lip was analyzed analogously to exemplary embodiment 1 and analyzed by means of electron microscopy and energy-dispersive X-ray fluorescence.
  • the coating could be detected in the entire area. Only cracks that led to a lump-like coating could be observed.
  • the torque after a test duration of 100 s was 0.3 ⁇ 0.01 Nm.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Sealing Devices (AREA)

Abstract

L'invention concerne une bague d'étanchéité en matériau élastomère pour charges dynamiques, la bague d'étanchéité étant à double courbure dans la région de la zone de contact, les conditions ci-après s'appliquant à la double courbure : rayon r1 << rayon r2 et r1 = k1/(111-SA)2, où r1 = rayon minimum de la lèvre d'étanchéité, r2 = rayon interne de la bague d'étanchéité, 40 mm ≤ k1 ≤ 640 mm, SA = dureté Shore A du matériau élastomère (sans unité); au moins 50 % de la largeur de contact de la zone de contact possédant un revêtement polymère à plasma réduisant l'abrasion ou un revêtement anti-friction.
EP22732212.0A 2021-06-09 2022-06-09 Joint présentant de bonnes propriétés anti-friction, son utilisation et son procédé de production Pending EP4351802A1 (fr)

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DE102021114904.5A DE102021114904A1 (de) 2021-06-09 2021-06-09 Dichtung mit guten Gleiteigenschaften, deren Verwendung und ein Verfahren zu deren Herstellung
PCT/EP2022/065654 WO2022258738A1 (fr) 2021-06-09 2022-06-09 Joint présentant de bonnes propriétés anti-friction, son utilisation et son procédé de production

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DE102023129446A1 (de) 2023-10-25 2025-04-30 Dekron Gmbh Verfahren und Vorrichtung zum Vorbehandeln einer Oberfläche von Behältern, wie Kunststoff-, Glas- oder Metallbehälter, vor einem Bedrucken
CN120141561B (zh) * 2025-02-27 2025-10-17 武汉理工大学 一种基于轮腿机器人的足端触地信息检测方法、装置、设备及介质

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US5246295A (en) 1991-10-30 1993-09-21 Ide Russell D Non-contacting mechanical face seal of the gap-type
DE3804284A1 (de) 1987-12-23 1989-07-13 Goetze Ag Wellendichtring
DE4018278C2 (de) 1990-06-07 1993-12-09 Bruss Dichtungstechnik Verfahren zur Herstellung eines Wellendichtringes
US6341782B1 (en) 2000-03-03 2002-01-29 Surface Technologies Ltd Lubricated seals having micropores
DE102006018491A1 (de) 2006-04-19 2007-10-25 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Flexible plasmapolymere Produkte, entsprechende Artikel, Herstellverfahren und Verwendung
DE102008002515A1 (de) 2008-06-18 2009-12-24 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Dichtungsartikel
DE102009027768B4 (de) 2009-07-16 2015-02-19 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Dichtungsartikel
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DE102012010603B4 (de) * 2011-06-29 2013-11-21 Carl Freudenberg Kg Beschichteter Dichtungsartikel
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