Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D7/00—Slip couplings, e.g. slipping on overload, for absorbing shock
  • F16D7/002—Slip couplings, e.g. slipping on overload, for absorbing shock the torque being transmitted and limited by yielding of an elastomeric race
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
  • F16D3/50—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive with the coupling parts connected by one or more intermediate members
  • F16D3/56—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive with the coupling parts connected by one or more intermediate members comprising elastic metal lamellae, elastic rods, or the like, e.g. arranged radially or parallel to the axis, the members being shear-loaded collectively by the total load
  • F16D3/58—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive with the coupling parts connected by one or more intermediate members comprising elastic metal lamellae, elastic rods, or the like, e.g. arranged radially or parallel to the axis, the members being shear-loaded collectively by the total load the intermediate members being made of rubber or like material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
  • F16D3/50—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive with the coupling parts connected by one or more intermediate members
  • F16D3/76—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive with the coupling parts connected by one or more intermediate members shaped as an elastic ring centered on the axis, surrounding a portion of one coupling part and surrounded by a sleeve of the other coupling part
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S474/00—Endless belt power transmission systems or components
  • Y10S474/902—Particular connection between rim and hub

Definitions

• the invention relates to a decoupling element made of elastic material, rubber or elastomer, intended for a rotary drive device, such as a pulley, roller, wheel, etc., in a power transmission system for compressor, alternator , starter or any type of accessory to be driven in rotation.
• the pulleys or other coupling means in rotation generally insert a ring-shaped rubber part A, of rectangular or profiled section, between a rim B and a central hub C.
• This part allows, by shear deformation between a position Ko at rest and K in rotation, a certain angular clearance to fulfill its decoupling function, in particular of frequency filter and damper, between the exciter (arrow E) and the answer (arrow R).
• This ring A is generally fixed by overmolding or adhesion on the internal and external faces, to cylindrical supports in metallic or plastic material, respectively forming an internal hub and an external rim. It is also generally advisable to adhere the ring to armatures, themselves force-fitted between the rim and the hub.
• the ring comprises successively concave and convex projections, with essentially continuous curvatures, opposite complementary shapes produced on the hub and the rim.
• the invention proposes to create zones in which the stresses are exerted essentially by shearing of the elastic material, in order to achieve in these zones the only power transmission function, independently of a torque limiting effect.
• the subject of the invention is a decoupling element made of deformable material, for example of elastic material, rubber or elastomer, intended to be interposed between the faces of two supports of a drive device having a central axis of rotation , the element being formed of a crown comprising at least two opposite faces and a central core. At least one of these faces and the face of the opposite support have complementary free projections in order to produce a meshing, the meshing of the crown creating at the feet projections of zones in which the central core works substantially in shear, these areas being regularly distributed over at least one of the faces of the crown.
• the central core means the continuous annular part of the crown without protuberance.
• the work of the crown is carried out by reducing the radial component of compression which, if not, becomes preponderant when the angular displacement increases.
• the torque / clearance linearity is then ensured, which leads to a constant stiffness over a wide angular range, for example greater than ⁇ 9 degrees, and therefore to a narrow resonance band.
• the faces of the crown and the meshing supports are cylindrical and parallel to the axis of rotation and / or radial and perpendicular to this axis, the projections being respectively radial and / or axial; - the projections are of constant or linearly variable profile in order to facilitate demoulding and assembly by self-centering when the crown fits on the supports;
• the projections are slots with a cross section, that is to say, whose lateral flanks are substantially perpendicular to the face of the crown on which they are formed; - the projections have lateral flanks with a flared section from this same face, with an average angle of up to 60 degrees relative to the radius, of trapezoidal, hyperbolic shape, with appropriate curvature (s), with advantageously of the draft in order to facilitate demolding or assembly by self-centering during the fitting of the free crown on the supports;
• the square of the ratio of the radii of the opposite cylindrical faces is inversely equal to the ratio of the angles at the center intercepting two projections of the respective faces , the opposite projections being periodically distributed from a basic pattern, in order to exert constant shear stresses over the entire crown and reversible when passing from one direction of rotation to the other;
• the crown is split to form an opening to facilitate its mounting by spacing during the introduction of the hub and by compression when it is inserted into the rim, so as to compensate for play between the parts.
• the crown according to the invention can be produced by molding, by extrusion followed by cutting into “washers” or cutting, or by injection / compression. In some cases, the product is formed flat, then rolled, and cut to make split crowns.
• the present invention is more generally part of a power transmission system, comprising a torque limiter or breaker, in order to eliminate its drive in the event of a blockage, and a rotation drive device integrating the element. decoupling.
• FIG. 1 and 1a schematic sectional views of a ring of elastic material of the prior art (already described);
• - Figures 2a and 2b views in partial section of decoupling rings with constant profile, respectively straight and flared, mounted between two complementary supports to schematically illustrate the shearing behavior of the crowns according to the invention;
• - Figure 3 an exploded view of an example of a drive device comprising a decoupling ring and supports with a straight and constant profile for radial assembly;
• FIG. 6 an exploded view of a variant comprising a crown and supports with variable self-centering profile
• FIG. 7 an exploded view of an example of a drive device comprising a crown with axial projections formed on its opposite radial faces;
• an exploded view of an example of a drive device according to the invention comprising a crown with radial projections in the form of cylindrical studs.
• an example of a cylindrical decoupling crown 2 according to the invention comprises a continuous annular central core 1 (limited in the crown by the dotted lines in the figure) and frank projections 2e, 2i extending radially along lateral flanks 22a projecting straight in this example.
• the projections, respectively 2e and 2i are regularly distributed alternately on, respectively, the outer face 21e and the inner face 21 i of the crown in order to preserve in particular good homogeneity of distribution of the masses.
• a crown section limited by a couple of successive internal and external projections then forms the basic pattern, repeated along the crown to form cylindrical fluted faces.
• the crown meshes between two supports, a central hub 3 and a rim 4, having faces 31 and 41 facing the complementary faces 21 i and 21e of the crown.
• the rim and the hub are made of metal or plastic in the example illustrated and the crown is made of rubber.
• the crown can be obtained by combining an elastomeric material and a metal reinforcement insert, or else several materials or the same elastomeric material of different densities: - a density for the core which is sheared and gives stiffness; a density for the external projections, with advantageously a textile reinforcement to reinforce the contact and fight against wear; and - a density for interior projections, with an optional textile reinforcement.
• the lateral flanks 22b of the projections 20e and 20i are radially flared from the central core 1.
• the projection has in cross section an “hourglass” shape of trapezoidal type, with an angle d '' average flare ⁇ 3 up to about 60 degrees, as shown.
• the power transmission is located at the feet of the projections 2e and 2i and is carried out predominantly in shear zones K-
• the section of the projections is dimensioned by appropriate ratios of the sections in the working areas, to limit their bending and thus the compression of the central core to favor the work in shear, the work in compression becoming negligible.
• the square of the radius ratio (R1 / R2) 2 cylindrical 21e faces and 21i is advantageously substantially equal to the inverse ratio of the central angles (0: 2/0: 1) intercepting two second projections and 2i of the respective faces. This dimensioning makes homogeneous and constant the shear stresses Ki exerted on the whole of the crown, and mainly located at the foot of the projections. This dimensioning also makes the shear reversible by passing from one direction of rotation to the other.
• FIG. 3 The exploded view of FIG. 3 as well as the sectional views of FIGS. 4a and 4b illustrate an example of a drive device 10 for a compressor of a motor vehicle.
• This device comprises the cylindrical decoupling ring 2 with a straight and constant profile, and the supports with complementary straight and constant profiles, a central hub 3 and a rim 4. These elements correspond to those of FIG. 2a for making a radial assembly.
• the hub 3 has a central gear 30 for driving the shaft 50 (FIGS. 4a and 4b) of the axis alternator X'X.
• the face 31 of the hub is provided with protrusions 3e with a straight and constant profile, complementary to the recesses 22i formed between two protrusions 2i of the face 21 i of the crown 2.
• the rim 4 has a wall 42 having on its face 41 protrusions 4i and hollows 44i intended to fit respectively in the hollows 22e and the projections 2e of the face 21e of the crown.
• the assembly is done by sliding the crown between the support parts.
• the parts should be finely indexed according to the desired clearance by any known indexing means (optical, mechanical, etc.).
• the height, that is to say the depth, of the grooves is a function of the torque of power to be transmitted, as well as their particular shape. This height can range, for example, from 1mm to 5mm.
• a slight radial clearance can be kept between the parts due to manufacturing tolerances. If the rim and the hub support it, this play can be zero and the crown will then be mounted with a light pressure without harming disassembly.
• the crown 2a is split.
• the opening 5 thus formed makes it possible to facilitate its mounting by spacing during the introduction of the hub 3 and by compression during its insertion into the rim 4, so as to compensate for the play between the parts.
• the spacing forces exerted by the hub on the crown are compensated by the compression exerted by the rim on this same crown. At the end of assembly, no play remains between the parts.
• the part can be directly molded or formed flat by injection / compression, then rolled to obtain a cylindrical part with the desired opening, and finally cut by cutting.
• the projections 2'e and 2'i of the crown, as well as the complementary projections 3'e and 4'i, respectively of the hub 3 'and of the rim 4 ′ have lateral flanks 22 ′ projecting in a radial right direction but with an variable axial profile along the axis X′X.
• the axial variation of the profiles is linear and forms projections with a trapezoidal axial profile.
• the small bases B1 of the trapezoidal projections for example 2'e
• the large bases B2 of the hollows for example 44'i, in which they must fit: an adjustment by self-centering product between protrusions and hollows during interlocking.
• the assembly of the parts is then less dependent on indexing. In this case, molding is preferable, but extrusion is also possible, with re-machining of the grooves after cutting.
• the presence of a variable profile as well as suitable draft also makes it possible to facilitate demolding during the manufacture of the crown.
• FIG. 7 relates to the embodiment of a cylindrical drive device comprising a crown 200 with axial projections 202 and 203, formed on its opposite radial faces 212 and 213.
• the faces 212 and 213 of the crown, the face 312 of the central hub 300 and the face 413 of the rim 400 which mesh are radial and perpendicular to the axis of rotation X'X.
• the projections 202 and 203 of the crown, the projections 302 of the hub and those 403 of the rim are axial.
• FIGS. 8a and 8b there appears an example of a crown 240 with combined radial and axial projections: radial projections, 24i and 24e, formed on the opposite axial faces, respectively internal 25i and external 25e, combined with axial projections, 262 and 263, formed on the opposite radial faces, respectively 272 and 273.
• This combined solution generally uses, to form the projections, an amount of material equivalent to that used in the non-combined radial or axial solutions , because the sections of the projections in combined solution can be, very approximately, twice as small.
• the projections are straight with constant profile, but the variants of sections and profiles described above can be applied to them. As before, the projections are alternated along the crown, so as to retain a central core of constant thickness, a balanced distribution of the masses and shear stresses.
• This ring 240 with combined projections, radial and axial, is coupled to a hub 340 and a rim 440 having complementary projections, 342 and 443, as illustrated by the axial and longitudinal sections in FIGS. 9a and 9b.
• the assembly forms a drive device 11 according to the invention.
• FIGS. 4a and 4b respectively equivalent, with the same reference signs: the rim 440 is centered by a frame 45, mounted on tubing by bearings 46.
• FIG. 10 shows, as a variant, an example of a drive device 12 comprising a ring 280 with radial projections in the form of cylindrical studs 282 and 283, respectively formed alternately on the opposite cylindrical faces, 292 and 293, of the crown 280.
• the hub 380 and the rim 480 have notches for housing the studs, respectively 382 and 483.
• the invention is not limited to the embodiments described and shown. It is possible to make the crown out of deformable plastic material, polypropylene, polyethylene or polyamide, or a composite material of type TPE (thermoplastic elastomer).
• the gear can be produced on a single pair of facing faces, between the crown and the rim or between the crown and the central hub, the other pair of faces being bonded.
• the invention is applicable to all drive devices having a filtering, damping or absorbing element.
• the accessories driven in rotation can for example be any motor or transmission element of a motor vehicle.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Gears, Cams (AREA)
• Pulleys (AREA)
• Motor Power Transmission Devices (AREA)
• Vibration Dampers (AREA)

Applications Claiming Priority (5)

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• 2003
  • 2003-11-07 FR FR0313124A patent/FR2853373B1/fr not_active Expired - Fee Related
  • 2003-11-26 US US10/721,884 patent/US7244185B2/en not_active Expired - Lifetime
• 2004
  • 2004-03-23 WO PCT/FR2004/000710 patent/WO2004090363A2/fr not_active Ceased
  • 2004-03-23 JP JP2006505746A patent/JP4728218B2/ja not_active Expired - Fee Related
  • 2004-03-23 EP EP04742320A patent/EP1608883A2/de not_active Withdrawn

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