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
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F1/00—Springs
  • F16F1/36—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers
  • F16F1/38—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers with a sleeve of elastic material between a rigid outer sleeve and a rigid inner sleeve or pin, i.e. bushing-type
  • F16F1/3835—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers with a sleeve of elastic material between a rigid outer sleeve and a rigid inner sleeve or pin, i.e. bushing-type characterised by the sleeve of elastic material, e.g. having indentations or made of materials of different hardness
• • 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
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F3/00—Spring units consisting of several springs, e.g. for obtaining a desired spring characteristic
  • F16F3/08—Spring units consisting of several springs, e.g. for obtaining a desired spring characteristic with springs made of a material having high internal friction, e.g. rubber
  • F16F3/087—Units comprising several springs made of plastics or the like material
  • F16F3/093—Units comprising several springs made of plastics or the like material the springs being of different materials, e.g. having different types of rubber
• • 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
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F2224/00—Materials; Material properties
  • F16F2224/005—Combined materials of same basic nature but differing characteristics

Definitions

• the present invention relates to an elastic articulation device.
• This type of device is intended to ensure the connection between two movable elements with respect to each other.
• an elastic articulation device as described for example in document FR-A-2 715 702, comprises a tubular external frame surrounding a central core also tubular and coaxial, this frame being made integral with the core by a mass of elastic material, of the natural rubber or elastomer type.
• the function of such a device is to provide the connection and filtering of vibrations between two vibrating elements, for example between the body of a vehicle and the wheel.
• the core is traversed by an axial central opening which makes it possible to make it integral with the body of a vehicle, while the outer sleeve is connected to the hub of one of the wheels of the vehicle. Reverse mounting is also possible.
• the mass of elastic material is made of a material with high damping or a material with low damping.
• a high damping leads to a strong stiffening, that is to say the increase in the value of the stiffness as a function of the frequency and the excitation amplitude. There is no material with high damping value, and which stiffens little.
• the present invention aims to provide an elastic articulation device which makes it possible to obtain an excellent compromise between stiffening and damping, while having good behavior in terms of guidance.
• an elastic articulation device intended to allow the articulation of two elements with respect to each other which, in known manner, comprises:
• a tubular external frame able to be fitted into the first element;
• a central tubular core capable of being connected to the second element and mounted coaxially inside said frame;
• This device is essentially characterized by the fact that said mass is bipartite and formed of two coaxial sleeves, one made of elastomeric material and the second of foamed and cast polyurethane.
• This cellular polyurethane has good dynamic behavior on vehicles. It stiffens the joint little as a function of the stressing speed, absorbs more and releases less energy than an elastomer element. Polyurethane is a material that achieves an excellent compromise between stiffening and damping, at any level of density.
• the elastomer is an excellent guide material, which is very complementary to polyurethane, which provides a filtering function.
• the internal sleeve is made of foamed and cast polyurethane
• - the outer sleeve is made of foamed and cast polyurethane
• elastomeric material is natural rubber
• - Said sleeves are separated by at least one intermediate coaxial frame; - Said sleeves are separated by two intermediate coaxial frames in contact with each other; - When said sleeves are separated by an intermediate frame, the inner wall of this intermediate frame as well as the outer wall of the central tubular core are shaped in such a way that they prohibit any relative movement in rotation of said sleeve interposed between these intermediate frame and core tubular;
• FIG. 2 is a sectional view of the device of Figure 1, along the section plane II-II;
• FIG. 4 - Figures 4, 6 and 8 are views of the devices of Figures 3, 5 and 7, respectively, along the section planes IV-IV, VI-VI and VIII-VIII.
• the device shown in Figure 1 essentially comprises an outer frame 1, a central core 2, and a mass of elastic material M which connects said outer frame and said central core.
• the external frame 1 has an elongated tubular shape, of axis XX ′, the cross section of which is circular. It is intended to be fitted into the bore of a first of the two elements to be articulated to one another.
• the central core 2 consists of a tube mounted coaxially inside the frame 1. It is intended to be connected to the second element to isolate vibrations, for example by means of a yoke.
• This tube has a central and axial bore. Its outer and inner walls have been numbered 20 and 21 respectively. We will return later to the particular shape and function of these walls.
• the external frame is made of plastic or metal, in particular steel or aluminum.
• the central core is made of a material capable of withstanding the mechanical stresses which the joint undergoes during its use. It is advantageously a metal such as steel or aluminum.
• the mass of elastic material M connects the two aforementioned parts together and provides articulation and filtering of vibrations.
• this mass M is bipartite and is formed by two coaxial sleeves, one made of elastomeric material and the second of foamed and cast polyurethane.
• the outer sleeve 1 is that which is in contact with the external reinforcement 1
• the inner sleeve is that which is in contact with the tubular core 2.
• the outer sleeve 3 is made of an elastomeric material such as natural rubber, while the inner sleeve 4 is formed of foamed and cast polyurethane.
• the polyurethane marketed by the German company ELASTOGRAN under the brand CELLASTO.
• a method of manufacturing such a polyurethane is for example described in the document EP-B-0 062 835 cited by way of reference.
• the two inner and outer sleeves are separated by a tubular and intermediate frame 5 which is coaxial with the outer frame 1 and the tubular core 2 and is interposed between them. Its length is intermediate between those of the two aforementioned elements, so that it emerges on either side of the frame 1, without reaching the length of the core 2.
• the outer sleeve 3 here consists of an elastomeric material. This constitutes a compact sleeve which extends from the opposite edges of the tubular frame 1 to the opposite ends of the intermediate frame 4.
• the lower part that is to say at the bottom of the FIG.
• small material returns 31 are supported on the flange 11 so as to form a retention of the sleeve in the axial direction (along the axis XX ') -
• symmetrical recesses 30 in arcs of a circle, radially opposite and opening out at the opposite ends of the reinforcements. In a manner known per se, these recesses contribute to modifying the behavior of the mass of elastomeric materials according to the direction of stress of the joint.
• the internal sleeve 4 extends between the intermediate frame 5 and the central core 2. It has a generally tubular shape with two ends forming a collar 40, which gives it the general appearance of a spool of wire.
• the internal wall 50 of the intermediate frame 5 and the external wall 21 of the central tubular core 2 are shaped in such a way that they prohibit any relative movement in rotation of the sleeve 4 which is interposed between them. More precisely, in this embodiment, these walls have a profile qualified as "quadrilobed”.
• this qualifier means a shape which is substantially inscribed in a square whose four sides are curved, of concavity turned towards the outside and whose angles are rounded.
• this quadrilobed shape also means a shape contained in a square, the four sides of which are curved, of concavity turned inward, and also with rounded angles.
• these walls could have a completely different profile preventing relative movement in rotation of the inserted sleeve 4.
• FIG. 3 The embodiment of Figures 3 and 4 has substantially the same structure as that described above. However, it differs therefrom by the fact that a second intermediate frame 6 is provided which is coaxial with the first 5 and which is arranged inside the latter, immediately in contact with it.
• the tubular frame 1, the core 2 and the intermediate frames 5 and 6 have, in this embodiment, a strictly circular section.
• the internal sleeve 4 extends from the internal wall of the second intermediate frame 6 to the opposite ends of the central core 2. In the end zones which project on either side of the intermediate frames, the thickness of foamed and cast polyurethane is relatively reduced compared to the rest of the sleeve. It is referenced 41 at this level.
• the presence of two frames facilitates assembly of the assembly.
• the elastomer sleeve is injected in the form of a mass between the intermediate frame 5 and the outer frame 1. It is adhered to it at the time of molding.
• the foamed and cast polyurethane sleeve is then inserted between the intermediate frame and the central tubular core.
• the presence of the end flanges 4 necessitates making this part in two distinct elements.
• the sleeve 4 is adhered between the central tubular core 2 and the second intermediate frame 6. This assembly is then fitted into the intermediate frame 5, which has been previously adhered to the sleeve 3.
• the polyurethane is poured into a mold into which the central core 2 has previously been introduced, as well as the armature 1 / intermediate armature 5 / sleeve 3 sub-assembly.
• the foamed and cast polyurethane is directly adhered to the elastomer sleeve.
• the elastomer sleeve 3 is external while the foam and cast polyurethane sleeve is internal.
• the arrangement of these two elements can easily be exchanged, so that the foamed and cast polyurethane constitutes the outer sleeve while the elastomer forms the inner sleeve.
• this can be made of plastic, steel or aluminum.
• this can be made of plastic, steel or aluminum.
• the use of compact polyurethane will be particularly appreciated because it makes it possible to ensure chemical bonding with the sleeve of cellular polyurethane foamed and cast according to the invention.
• foamed and cast polyurethane sleeves begins with the mixing of a polyol, an isocyanate and a crosslinking agent.
• the products used are toxic and require great precautions for their implementation.
• This mixture is poured with CO 2 gas into a mold. Cross-linking of the mixture or baking takes place in the mold. The cooking time is approximately 30 min at 80 ° C. The part is then removed from the mold and deburred and then thermally stabilized. The density of the parts obtained by this process varies between
• This new articulation in its different versions, allows to obtain the dynamic advantages of the elastomer sleeve and of the foamed and cast polyurethane sleeve.
• the foam and cast polyurethane part has good dynamic behavior on the vehicle. It stiffens less as a function of the stressing speed, absorbs more and releases less energy than an elastomer element. Foamed and poured polyurethane is a material that achieves an excellent compromise between stiffening and damping for any level of density.
• the elastomer element which is an excellent guide material can be very complementary with the foamed and cast polyurethane which will play the role of filtering.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Springs (AREA)
• Vibration Dampers (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (3)

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Family Cites Families (6)

• 2003
  • 2003-04-25 EP EP03740669A patent/EP1618315A1/de not_active Withdrawn
  • 2003-04-25 AU AU2003304063A patent/AU2003304063A1/en not_active Abandoned
  • 2003-04-25 WO PCT/FR2003/001313 patent/WO2004097245A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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