FR2913740A1 - Metallic flexible coupling device for e.g. coaxial drive element, has spring for rotatively connecting lever bosses for driving driven element by drive element at level of junction zone with gelled polymer-matrix containing lubricating oil - Google Patents

Abstract

The device (1) has lever bosses (3, 5) rotatively integrated with a co-axial drive element (2) and a co-axial driven element (4), respectively, and determining a junction zone (10) between the two elements. A connection spring (21) rotatively connects the lever bosses for rotatively driving the driven element by the drive element at a level of the junction zone. The junction zone comprises gelled polymer-matrix (22) containing lubricating oil.

Description

Flexible coupling device

  The invention relates to a flexible metallic coupling device between a driving element and a substantially coaxial driven element, comprising at least one connecting member rotating the driving element and the driven element, via a first hub and a second hub interconnected at a junction area covered by the connecting member.

  It is known to use oil or grease to lubricate a connecting member and two hubs belonging to a coupling device. However, as the coupling device operates, the oil or grease has a tendency to deteriorate and escape outside the area where the connecting member and the two hubs are located. Thus, it is necessary to regularly renew the oil or grease to ensure lubrication of the coupling device which multiplies the maintenance operations.

  In US 4,044,572 there is provided a coupling device comprising two hubs interconnected by a spring. The spring and the two hubs are lubricated with grease. The grease is held in a housing equipped with grease ports.

  In order to avoid loss and reloading of lubricant, it is known to use certain materials at the level of the connecting member that does not require lubrication.

  US Pat. No. 2,904,976 proposes a coupling device comprising a connecting member corresponding to several blocks. Each block is inserted into a corresponding slot passing through two hubs of the coupling device. These blocks are made of a plastic material such as nylon, intended to limit the friction between each block and the hubs.

  However, the wear of these blocks requires lubrication after a certain period of use.

  In US 2,924,954 there is provided a coupling device comprising a connecting member corresponding to a ring gear made of a plastic material, such as nylon.

  However, such a coupling device does not allow to completely get rid of lubrication.

  In WO 89/09346 and WO 89/109347, there is provided a coupling device comprising two hubs interconnected by a spring. The spring is coated on its surface with a material, such as polyurethane or nylon, improving the sliding between the spring and the hubs. The wear of the hubs and / or the spring is thus reduced. Coatings prevent lubrication of the coupling.

  However, such a coupling device is complex and expensive to implement.

  An object of the present invention is to provide a powerful coupling device while maintaining lubrication that is simple to implement, durable and effective.

  According to a first aspect, the subject of the invention is a flexible metallic coupling device between a substantially coaxial driven element and a driven element, of the type comprising:

  a first hub and a second hub that rotate respectively with the driving element and the driven element and defining between them a junction zone and

  at this junction zone, at least one connecting member in rotation of the two hubs for rotating the shaft driven by the driving shaft;

  Characterized in that the junction zone comprises at least one gelled polymer matrix containing a lubricating oil.

  The coupling device of the invention has the following non-exhaustive advantages:

  long-lasting and efficient lubrication thanks to the lubricating oil contained in the polymer matrix;

  optimum lubrication through the use of oil rather than lubrication;

  - lubrication integrated into the coupling that does not require regreasing;

  a respect of the environment thanks to the matrix which limits the oil leaks and allows an adequate release of the oil;

  a non-external contamination thanks to the matrix which is a protective envelope;

  a simple lubrication to be implemented thanks to the gelled structure of the polymer matrix;

  a lack of maintenance allowing continuous operation of the coupled machines.

  According to other embodiments, the device comprises at least one of the optional features below taken alone or in all the possible combinations; Said at least one connecting member comprises a spring overlapping the junction zone over its entire periphery and designed to cooperate with radial grooves formed respectively in the first and second hubs; the gelled polymer matrix at least partially coats the spring; the gelled polymer matrix coats the upper part of the spring; said at least one connecting member comprises two cylindrical half-housings connected together at the junction zone and each comprising an internal ring gear intended to cooperate with a ring gear formed respectively in the first and second hubs; said at least one gelled polymer matrix coats the ends of the first and second hubs respectively at the junction zone between the toothed rings respectively of the first and second hubs; said at least one gelled polymer matrix coats the teeth of the toothed crowns respectively of the first and second hubs; the gelled polymer matrix comprises a lubricating oil content of between 60 and 98% by weight; the polymer matrix has a fluidification temperature greater than or equal to 110 C; the degree of crosslinking of the polymer of the polymer matrix is between 0.05% and 5%, the polymer of the polymer matrix is formed from monomers of valence greater than or equal to 3 allowing crosslinking of the polymer.

  According to a preferred embodiment, the gelled polymer matrix comprises a lubricating oil content of between 60 and 98% by weight. The gelled polymer matrix has the particularity of being fat at ambient temperature, namely that lubricating oil is exuded from the gelled polymer matrix at ambient temperature thus ensuring lubrication at the contact (s) between the connecting member and the first and second hubs. Preferably, the gelled polymer matrix comprises a three-dimensional network of polymer. The lubricating oil is thus located between the meshes of the three-dimensional network and produces a swelling of the polymer matrix. By way of example, the lubricating oil is chosen from the groups consisting of high performance mineral oils and synthetic oils with very high performances for the lubrication of the gears. For example, mention MOBILGEAR Series 600 oil or MOBILGEAR XMP oil. In general, the gelled polymer matrix is obtained either by chemical crosslinking or by physical crosslinking.

  Chemical crosslinking is characterized by the formation of covalent nodes obtained: by a stepwise polymerization reaction; by chain copolymerization; or - by random bypass.

  The stepwise polymerization involves the reaction of monomers carrying functions that react with each other and with an average valence greater than or equal to two. By way of example, the functions that react with each other are chosen from the pairs of alcohol and isocyanate, alcohol and epoxide, alcohol and carboxylic acid, amine and epoxide, amine and carboxylic acid. The polymer is preferably synthesized in the lubricating oil. Thus, the monomers forming the polymer are soluble in the lubricating oil. The monomers are then chosen from the group consisting of ethylenic or diene polyolefins carrying at least two terminal or pendant functions of the alcohol, isocyanate, acid or amine type. These terminal or pendant functions react with multifunctional organic molecules.

  The method for using the gelled polymer matrix obtained by step polymerization comprises two steps. In a first step, the various constituents are pre-polymerized in the oil, without exceeding the freezing point. The freezing point corresponds to the critical temperature and pressure beyond which the matrix is gelled. Following this prepolymerization, a pre-gel of high viscosity is thus obtained. Then, in a second step, the pre-gel is introduced into the coupling device of the invention and then heated in order to obtain crosslinking in situ. For example, the polybutadiene dihydroxytelechelic molecular weight 45000g / mol, hexamethylene diisocyanate, the ratio of NCO / OH functions being between 0.5 and 2, are mixed in the lubricating oil in the presence of a SnCI4 type catalyst. The amount of SnCl4 introduced varies, in general, between 100 and 3000 ppm depending on the nature of the oil and the desired polymerization kinetics. The reaction medium is heated at about 80 ° C. for about 2 hours. The viscosity of the reaction medium increases significantly, from 1 to 1000 Cp. The pre-el is then introduced into the coupling device. It is then heated for 1 hour to obtain a reticulate. Beyond the gel point, the polymer matrix comprising the lubricating oil is gelled. Another example of a polymer resulting from a stepwise polymerization of poly (butadiene) dihydroxytelechelic hydrogen of mass 100,0008 / mol of Mobil Gear 629 oil. Between 3.10 g and 2 g of diisocyanate of the Hewamethylene diisocyanate type is added to the reaction medium in the presence of 500ppm of SnCI4. The reaction medium is heated at 120 ° C. for 45 minutes. The viscosity increases without reaching the freezing point; the product is introduced into the flexible coupling device via a lubricating orifice and is heated for 30 minutes. Crosslinking thus takes place in situ leading to the formation of a gelled oil.

  Moreover, the random cross-linking polymerization involves polymers obtained such as polyolefins of the EPR or ethylene-propylene-rubber type, of the EPDM or ethylene-propylene-diene type, and the copolymers of ethylene with olefins of formula CnHZn with n greater than or equal to 4, such as, for example, butene, hexene or octene. These random bridging polymers are heat-soluble in the lubricating oils used, and gel the medium once cooled. This viscosified oil is then introduced into the coupling device of the invention together with the catalyst dispersed in the oil. The mixture is then heated in situ to create bridges between the polymer chains. EPR polymers and copolymers of ethylene and higher olefins can generally be cross-linked by means of organic peroxide, such as dicumyl peroxide or tert-butyl cumyl peroxide. Similarly, EPDMs can generally be crosslinked by means of sulfur. In general, the crosslinking improves the gelling properties of the abovementioned polymers. Example of Polymers Obtained by Random Bridging Polymerization Example 1: 10 g of a poly (ethylene-co-oct-1-ene) copolymer is solubilized in Mobil Gear XMP150 oil at 150 ° C. for 4 hours to yield a viscosified oil . The latter is subsequently mixed with 0.1 parts of a dicumyl peroxide responsible for crosslinking between the chains. The gelled oil is thus obtained in situ. Example 2: 10 g of a poly (ethylene-co-propylene-co-ethylidene-2-norbornene) EPDM containing about 70% ethylene and 0.5% 5-ethylidene-2-norbornene, is solubilized in 100 g of Mobil Gear 629 oil at 150 ° C. for 4 hours. The product is subsequently mixed with 0.1 parts of a peroxide or 0.3 parts of sulfur to cure. The gelled oil is formed in situ.

  The physical crosslinking corresponds to the chemical crosslinking described above with reversible inter-linkages. For this purpose, the bridging between the polymer chains is ensured by the establishment of low energy, typically Van der Waals, medium energy molecular interaction, typically of hydrogen bonding, or carried out by coalescence into nodules of polymer blocks belonging to to an ABC type block copolymer. Cluster coalescence is understood here to mean that certain blocks are insoluble in the medium and combine to form modules otherwise known as physical cross-linking nodes. ABC block copolymers are preferably used. Preferably, the block B is chosen from the polymers soluble in the lubricating oils used. In particular, the block B is chosen according to the polarity of the lubricating oil which determines the solubility of the block B in the lubricating oil. By way of example, block B is chosen from the groups consisting of polyethylene and its copolymers with olefins of formula CmH2m with m greater than or equal to 3, such as propylene, butylene, hexene or octene. with polydienes such as polybutadiene or polyisoprene or with alkyl poly (metha) acrylates having at least 6 carbon atoms such as octadiene polyacrylate or hexadiene polyacrylate. Blocks A and C preferably have little or no affinity with the lubricating oil used. Block A and block C are organized, in general, by coalescence into nodules in order to form the nodes of the network. Blocks A and C are thus chosen from polymers that are insoluble in the lubricating oils used.

  By way of example, mention may be made of polystyrene, alkyl polyalkyl acrylates having a number of carbons of between 1 and 4, hydrophilic or water-soluble polymers such as polyethylene oxide, polyacrylic acid and polysaccharides. polyvinylpyrrolidone, vinyl polyacetate or polyvinyl alcohol.

  In the case where block A and block C are identical, block copolymers of type ABC are of the ABA type. These block copolymers of the ABA type are, for example, chosen from poly (styrene-butadiene-styrene), poly (styrene-isoprene-styrene), poly (styrene-ethylene-butylene-styrene) copolymers, poly (styrene - ethylene - styrene), poly (methyl methacrylate - butadiene - methyl methacrylate), poly (methyl methacrylate - isoprene - methyl methacrylate), poly (methyl methacrylate - ethylene - methyl methacrylate), poly (methyl methacrylate - (ethylene - butylene) methyl methacrylate), poly (ethyl acrylate - isoprene - ethyl acrylate), poly (ethyl acrylate - butadiene - ethyl acrylate), poly (acrylate ethyl (ethylene-butylene) ethyl acrylate, poly (styrene-stearyl acrylate-styrene), poly (methyl methacrylate-stearyl acrylate-methyl methacrylate), poly (ethylene oxide isoprene) ethylene oxide), poly (ethylene oxide-butadiene) ). In the case where block A is identical to block C, the polymer preferably has a molar mass greater than 80,000 g / mol. In addition, the mass fraction of block B is preferably greater than the mass fraction of block A. In general, the polymer or copolymer of the polymer matrix comprises at least one block of polymers whose glass transition temperature is less than 20. C, or even between -80 and 10 C.

  Examples of polymers with physical crosslinking

  Example 1: 10 g of a block terpolymer of poly (styrene-b-ethylene-butylene-b-styrene) molecular weight of 120 000 g / mol and containing about 30% of styrene is solubilized in 100 g of Mobil Gear 629 oil at 150 C for 6h. The product is castable at temperatures above 100 C but gels at a lower temperature.

  Example 2: 10 g of a block terpolymer of poly (styrene-b-ethylene-butylene-bstyrene) grafted maleic anhydride at 1% and containing at most 40% of styrene is solubilized in 100 g of Mobil Gear XMP oil 150 to 150 ° C for 6 hours. The product is castable at temperatures above 100 C is gelled at lower temperature.

  Other characteristics and advantages of the invention will become apparent from the following description, given by way of example and with reference to the appended drawings, in which: FIG. 1 represents an external perspective view of a FIG. 2 represents a diagrammatic perspective view partially broken away of the coupling device of the invention; FIG. 3 is a diagrammatic view from above of the coupling device without the half-coupling; FIG. 4 represents a schematic and perspective view of an exemplary embodiment of a coupling member of the coupling device of the invention, FIG. 5 represents an axial section of a FIG. variant of a coupling device of the invention.

  Figures 1 to 3 show a coupling device 1 according to the invention comprising a first hub 3 for receiving a driving element 2 and a second hub 5 for receiving a driven element 4. The elements respectively leading 2 and led 4 are mounted in the hubs, respectively 3 and 5, and integral in rotation with these hubs by appropriate mechanical means and of known type, such as keys, by shrinking or by splines. The coupling device 1 according to the invention is metallic, or entirely made of metal.

  The first and second hubs 3 and 5 respectively comprise a first shoulder 7 and a second shoulder 9 delimiting between them a junction zone 10. The first and second shoulders 7 and 9 each comprise radial grooves respectively 11 and 13 arranged opposite each other. in such a way that the radial grooves extend from the first shoulder 7 to the second shoulder 9.

  Furthermore, the first hub 3 comprises a first sealing ring 15 and the second hub 5 also comprises a second sealing ring 17. The first and second hubs 3 and 5 are interconnected by a connecting member covering the zone According to the embodiment of FIGS. 1 to 3, the connecting member comprises a spring 21 which overlaps the junction zone 10 over its entire periphery and is designed to cooperate with the radial grooves 11 and 13 formed respectively in the first and second grooves. and second hubs 3 and 5. Thus, the spring 21 enters the radial grooves 11 and 13. The spring 21 covers the entire periphery of the shoulders 7 and 9 and is formed either in one piece for the small size couplings or several segments, for example two segments 21a as shown in Figure 4. The spring 21 is formed of a succession of "S" having portions 21b rectilinear and parallel and connected between e they are curved portions 21c. The rectilinear portions 21b penetrate into the grooves 11 and 13. The spring 21 makes it possible advantageously to provide an elastic connection between the first and second hubs 3 and 5. Preferably, the radial grooves 11 and 13 have adjacent sides convex type curves. Due to the curved shape of the radial grooves 11 and 13 and the elasticity of the spring, the coupling device 1 of the invention has a progressive torsional stiffness. As an indication, a coupling device of low torsional stiffness is comparable to a damper. Indeed, the more the coupling is rigid in torsion, the more the effort that the coupling transmits is immediate.

  The lubrication between the spring 21 and the radial grooves 11 and 13 is provided by a gelled polymer matrix 22 comprising a lubricating oil. The gelled polymer matrix 22 is of the type previously described. The gelled polymer matrix 22 at least partially coats the spring 21 and more particularly said matrix 22 coats the upper part of the spring 21 so that the lower portion of the rectilinear portions 21b of said spring 21 penetrates into the radial grooves 11 and 13. During operation of the coupling device 1 of the invention and as will be seen later, the oil contained in the polymer matrix 22 is exuded as the coupling device heats which allows to lubricate the contact areas between the spring 21 and the radial grooves 11 and 13.

  The spring 21, the gelled polymer matrix 22 and the junction zone 10 of the first and second hubs 3 and 5 are also covered by two cylindrical half-housings 23 and 25. The two cylindrical half-housings 23 and 25 are arranged screwed and are closed together, for example, by means of bolts 27 placed in the corresponding orifices 29 and 31 belonging to each cylindrical half-housing respectively 23 and 25. According to a variant shown in FIG. Coupling 1 of the invention comprises a first hub 41 intended to receive a driving element 2 and a second hub 43 intended to receive a driven element 4. As for the previous embodiment, the elements respectively leading 2 and led 4 are integral. in rotation with the hubs 41 and 43 respectively by appropriate mechanical means of known type. The first hub 41 has a first ring gear 45 and the second hub 43 has a second ring gear 47. The first hub 41 and the second hub 43 define a junction zone 52. According to this variant, the connecting member is formed by two cylindrical half-housings 53 and 55 each comprising an inner ring gear 57 and 59 respectively intended to cooperate with the toothed rings 45 and 47 respectively formed in the hubs 41 and 43. The two cylindrical half-housings 53 and 55 are interconnected at the junction zone 52 by means of bolts 61 inserted into corresponding ports 63 and 65 present in each cylindrical half-housing respectively 53 and 55. Two seals 73 and 75 seal between the half cylindrical housings 53 and 55 and the first and second hubs 41 and 43. In this variant, the end of the hub 41 between the ring gear 45 and the junction zone No. 52 is coated with a gelled polymer matrix 71 containing a lubricating oil and likewise the end of the hub 43 between the ring gear 47 and the junction zone 52 is coated with a gelled polymer material 72 containing a lubricating oil . According to another variant not shown, the matrix 71 can coat the teeth of the ring gear 45 and the matrix 72 can coat the teeth of the ring gear 47. According to another variant not shown, the dies 71 and 72 can form a only matrix. In operation, the first hub 3 and 41 is rotated by the drive element 2. The link member 21, 53 and 55 then transmits the rotational movement to the second hub 5 and 43 which rotates the element. 4. The frictional movements between the connecting member 21, 53 and 55 and the first and second hubs 3, 5, 41 and 43 due to the rotational movement involve an increase in the temperature at the gelled polymer matrix 22 , 71 and 72. Thus, the minimum amount of lubricating oil contained in the gelled polymer matrix 22, 71 and 72 is released to lubricate the contact between the connecting member 21, 53 and 55 and the first and second hubs. 3, 5, 41 and 43. The gelled polymer matrix 22, 71 and 72 makes it possible to limit the leakage of oils while ensuring that the lubricating oil is sufficiently exudated to lubricate the coupling device 1 of the invention.

  In the particular case where the connecting member corresponds to a spring 21, the lubricating oil thus released by the matrix 22 is spread between the spring 21 and the radial grooves 11 and 13 of the shoulders 7 and 9. In the case particular where the connecting member corresponds to the two half cylindrical housings 53 and 55 each having a ring gear 57 and 59, the lubricating oil thus released by the die 71 and 72 is spread between the teeth of the ring gear 57 and 59 two half-housings 53 and 55 and the teeth of the toothed crowns respectively 45 and 47 of the first and second plates of the first and second hubs respectively 41 and 43.

  In any case, the coupling device 1 of the invention is lubricated with a minimum necessary and effective amount of lubricating oil contained in the gelled polymer matrix 22, 71 and 72. The coupling device according to the present invention comprises the following non-exhaustive benefits.

  The coupling device of the invention tolerates and absorbs: radial misalignments, namely that the axes of revolution of the two hubs are parallel but not coincidental; angular misalignments, namely that the axes of revolutions of the two hubs intersect at a non-zero angle; and axial displacements, namely the variation in distance between the faces of the two hubs. This characteristic is made possible in particular by the structure of the gelled polymer matrix which is able to deform and recover its original shape after deformation.

Claims (11)

claims   1.- Coupling device (1) flexible metal between a substantially coaxial driven element (2) and a driven element (4), of the type comprising: - a first hub (3; 41) and a second hub (5; ) integral in rotation respectively with the driving element (2) and the driven element (4) and defining between them a junction zone (10; 52), and - at this junction zone (10; 52) at least one connecting member (21, 53, 55) rotating the two hubs (3, 5; 41, 43) for rotating the driven element (2) by the driving element (4), characterized in that the junction zone (10; 52) comprises at least one gelled polymer matrix (22; 71,72) containing a lubricating oil.   2. A coupling device according to claim 1, characterized in that said at least connecting member comprises a spring (21) overlapping the junction zone (10) over its entire periphery and intended to cooperate with radial grooves (11). 13) respectively in the first and second hubs (3, 5).   3.- coupling device according to claim 1 or 2, characterized in that the gelled polymer matrix (22) at least partially coats the spring (21).   4. A coupling device according to any one of claims 1 to 3, characterized in that the gelled polymer matrix (22) coats the upper part of the spring (21).   5. - Coupling device according to claim 1, characterized in that said at least connecting member comprises two cylindrical half-housings (53, 55) interconnected at the junction zone (52) and each having a internal ring gear (57, 59) intended to cooperate with a ring gear (45, 47) formed respectively in the first (41) and second (43) hubs.   6. A coupling device according to claim 1 or 5, characterized in that said at least one gelled polymer matrix (71, 72) covers the ends of the first (41) and second (43) hubs respectively at the level of the junction (52) between the toothed rings (45, 47) respectively of the first (41) and second (43) hubs.   7. - Coupling device according to claim 1 or 5, characterized in that said at least one gelled polymer matrix (71, 72) surrounds the teeth of the toothed rings (45, 47) respectively of the first (41) and second (43). ) hubs.   8. Coupling device according to any one of the preceding claims, characterized in that the gelled polymer matrix (22; 71; 72) comprises a lubricating oil content of between 60 and 98% by weight.   9. Coupling device according to any one of the preceding claims, characterized in that the polymer matrix (22; 71, 72) has a fluidification temperature greater than or equal to 110 C.   10. Coupling device according to any one of the preceding claims, characterized in that the crosslinking rate of the polymer of the polymer matrix (22; 71, 72) is between 0.05 and 5%.   11. A coupling device according to any one of the preceding claims, characterized in that the polymer of the polymer matrix (22; 71, 72) is formed from monomers of valence greater than or equal to 3 allowing crosslinking of the polymère.15