WO2021123543A1

WO2021123543A1 - Decoupling element for a motor mount comprising a non-newtonian fluid

Info

Publication number: WO2021123543A1
Application number: PCT/FR2020/052289
Authority: WO
Inventors: Geoffroy CAPOULUN
Original assignee: Valeo Systemes Thermiques
Priority date: 2019-12-18
Filing date: 2020-12-07
Publication date: 2021-06-24
Also published as: FR3105101A1; FR3105101B1

Abstract

A motor mount (16), in particular for a motor fan assembly (10) of a heating, ventilation and/or air conditioning system of a vehicle, comprises two coaxial collars (20; 22), wherein a first collar (20) is capable of receiving one or more elements of an electric motor (14) and a second collar (22) is capable of being attached to a housing (18) intended to form a structural element, and a decoupling element (24) positioned between the first collar (20) and the second collar (22). The decoupling element (24) is produced entirely or partially with a dilatant non-Newtonian fluid.

Description

DECOUPLING ELEMENT FOR AN ENGINE MOUNT INCLUDING A NON-NEWTONIAN FLUID

Technical area

The present invention relates to an engine support, in particular an electric motor support, in particular for a ventilation device for a motor vehicle heating, ventilation and / or air conditioning installation.

Prior art

[0002] In a heating, ventilation and / or air conditioning installation for a motor vehicle, a motor-driven fan unit ensures the creation of an air flow intended to supply the vehicle interior. The temperature of the air flow can be regulated to achieve the effect of heating, ventilation and / or air conditioning.

[0003] The motor-fan unit allows the flow of air to enter and circulate in the ventilation, heating and / or air conditioning system to the outlets, where the air enters the passenger compartment.

[0004] The motor-fan unit in known manner comprises an electric motor, for example a brushed motor, on which a wheel is mounted to set the air in motion. The motor-fan unit also includes a motor support which includes an inner ring configured to accommodate the electric motor and an outer ring suitable for being attached to a housing of the heating, ventilation and / or air conditioning installation.

[0005] The vibrations caused by the engine can propagate from the inner ring to the outer ring of the motor support. These vibrations can be felt in the vehicle, causing inconvenience to the occupants of the vehicle.

[0006] This is why a decoupling means is arranged between the inner ring and the outer ring. Conventionally, a decoupling means is a ring made of flexible material or a viscoelastic mechanical subsystem. The decoupling means thus have flexibility making it possible to limit the propagation of vibrations from the inner ring to the outer ring of the motor support. For the efficiency of the decoupling, it is desirable for the stiffness of the decoupling means to be as low as possible.

[0007] In addition, the housing of the heating, ventilation and / or air conditioning installation, to which the motor support is connected, is also subjected to stresses, caused for example by the movements of the vehicle. These stresses are transmitted to the electric motor mounted on the motor support, through the housing of the heating, ventilation and / or air conditioning installation. These stresses can lead to deterioration of components of the motor-fan assembly, in particular of the wheel, in the event that the amplitude of the displacement of the motor causes the wheel to come into contact with a part of the housing of the heating, ventilation installation. and / or air conditioning, and / or of the decoupling system in the case where the displacements induce stresses greater than the elastic limit of the decoupling system.

[0008] To limit the risk of deterioration of the motor-fan unit under the effect of these constraints, it is thus preferable that the decoupling means be relatively rigid.

[0009] It is therefore understood that the two objectives mentioned above cannot be easily achieved with a decoupling element made of elastomeric material.

[0010] Furthermore, it is known from application FR-A-2 974 464, a motor support comprising an outer ring and a member for receiving an electric motor. The receiving member is connected to the outer ring by decoupling means. The decoupling means comprises an adaptive device capable of modifying at least one mechanical characteristic of the decoupling means, in particular a stiffness or a dimension of the decoupling means. However, this adaptive, active device is complex. Its installation can also be tricky.

The aim of the present invention is to provide an engine support, in particular for a heating, ventilation and / or air conditioning installation for a motor vehicle, which does not have at least some of the drawbacks mentioned above.

summary The present description proposes an engine support, in particular for a motor-fan unit of a heating, ventilation and / or air conditioning installation of a vehicle, comprising:

- two coaxial rings of which a first ring is able to receive one or more elements of an electric motor and a second ring is able to be fixed on a housing intended to form a structural element, and

- a decoupling element interposed between the first ring and the second ring, the decoupling element being produced in whole or in part from rheo-thickening non-Newtonian fluid.

[0013] Thus, the non-Newtonian fluid allows an adaptation of the rigidity of the decoupling element, depending on the stress which applies to this decoupling element. Advantageously, this adaptation is passive, in that it does not require any actuator.

[0014] According to particular embodiments, the motor support may include one or more of the following characteristics, taken alone or in combination:

- the non-Newtonian fluid has its own shape in the absence of stress;

- the non-Newtonian fluid is made of a material of the D3o ® brand;

- the decoupling element is entirely of rheo-thickening non-Newtonian fluid;

the decoupling element comprises at least one stud, arranged between the first ring and the second ring, the stud preferably defining a cavity receiving rheo-thickening non-Newtonian fluid, the at least one stud being, more preferably, taken in sandwich, in the direction of the axis of the two coaxial rings between a part of the first ring and a part of the second ring;

- the pad is made of an elastomeric material, for example of SEBS, or of a rheo-thickening non-Newtonian fluid having a specific shape in the absence of stress;

the stud has a cylindrical shape, in particular of rectangular or round section, preferably such that a rigidity of the stud in a tangential (or orthoradial) direction is less than a rigidity of the stud in an axial or radial direction; - the stud has a height, measured in the direction of the common axis of the two coaxial rings, between 11 and 15 millimeters and / or a width, measured in the radial direction with respect to the common axis of the two coaxial rings, between 8 mm and 12 mm, and / or a length, measured in an orthoradial direction with respect to the common axis of the two coaxial rings, between 11 and 15 mm;

- the first ring has a radial projection, the second ring has a housing, the radial projection being received in the housing, the stud being received at least partially in the housing, in a sandwich, in the direction of the common axis of the two rings coaxial, between the radial projection and a wall of the housing, normal to the common axis of the two coaxial rings;

- the first ring comprises at least a second radial projection, the second ring has at least a second housing, the second radial projection being received in the second housing, a second stud being received at least partially in the second housing, in sandwich, in the direction of the common axis of the two coaxial rings, between the second radial projection and a second wall of the second housing, normal to the common axis of the two coaxial rings, the first and second radial projections and the first and second walls being shaped so that in the event of movement of a ring relative to the other ring, only one of said stud and the second stud is compressed;

- the stud and / or the second stud, where appropriate, defines a cavity receiving rheo-thickening non-Newtonian fluid, the second ring and / or the first ring comprising an opening opening into the housing, making it possible to fill the cavity with fluid rheo-thickening non-Newtonian;

- the cavity in the stud is cylindrical in shape, possibly with an undercut facilitating moldability, a ratio between the height of the cavity, measured in the direction of the common axis of the two coaxial rings, and the largest dimension of the section transverse of the cavity, measured in a plane normal to the direction of the common axis of the two coaxial rings, preferably being between 1, 1 and 1, 5;

- the non-Newtonian fluid in the cavity is liquid, in the absence of stress;

- the non-Newtonian fluid in the cavity is chosen from: an aqueous solution of polyvinyl alcohol and borax (or "slime"), a fluid of the D3o ® brand, a aqueous solution of corn starch;

- the opening comprises a frustoconical portion, of increasing section from the cavity towards a free surface of the second ring and / or the first ring;

- the opening comprises a cylindrical portion from the free surface of the second ring and / or the first ring towards the cavity;

- The stud forms a rim covering the walls of the opening of the second ring and / or the first ring;

- The motor support comprises a plug closing the cavity and / or the opening, where appropriate, preferably in a sealed manner to the rheo-thickening non-Newtonian fluid.

- The decoupling element comprises a plurality of pads, preferably six pads, the pads being, more preferably evenly distributed angularly around the common axis of the two rings;

- The pads are interconnected, the pads being in particular integrally formed, to form a decoupling element in the form of a decoupling ring;

- the two coaxial rings are concentric, a first ring or inner ring being disposed radially inside a second ring or outer ring

According to another aspect, there is proposed a motor-fan unit for vehicle ventilation installation, vehicle heating, ventilation and / or air conditioning, comprising an electric motor, a fan wheel, driven in rotation by the motor electric, and a motor support as described above, the motor being fixed to one of the rings of the motor support.

According to particular embodiments, the motor-fan unit may include one or more of the following characteristics, taken alone or in combination:

- the stud has a rigidity in a tangential (or orthoradial) direction such as the resonance frequency of the mass-spring system composed of the internal ring, as mass, and of the decoupling element, in particular of the decoupling ring , where appropriate, as a spring, at room temperature, is less than the frequency of the lowest fundamental harmonic of the system consisting of the motor and the motor support, at the minimum speed of rotation of the engine. It is considered that the frequency of the fundamental harmonic is the frequency of the harmonic of order equal to the minimum between the number of magnetic poles of the rotor and the number of magnetic poles of the stator;

- the rigidity of the pad in an axial direction, respectively radial, is such that the inner ring moves less than 0.5 mm in all directions, when the engine is mounted on the engine support and that is varied, in all directions, the force exerted by the weight of the engine on the engine mount; and

- the decoupling element has an inertia, in the direction of gravity, greater than the combined mass of the support and the motor

Brief description of the drawings

[0017] Other features, details and advantages will become apparent on reading the detailed description below, and on analyzing the accompanying drawings, in which:

[0018] [Fig. 1] schematically shows an example of a fan device for a motor vehicle heating, ventilation and / or air conditioning installation.

[0019] [Fig. 2] schematically shows in perspective a first example of a motor support device which can be implemented in the fan device of FIG. 1.

[0020] [Fig. 3] shows schematically and partially in section the engine support device of Figure 2, according to a first radial sectional plane.

[0021] [Fig. 4] shows schematically and partially in section a variant of the engine support device of FIG. 2, according to a second radial section plane.

[0022] [Fig. 5] shows schematically and partially in section a second example of a motor support device that can be implemented in the fan device of FIG. 1, according to a first radial sectional plane.

[0023] [Fig. 6] shows schematically and partially in section the engine support device of FIG. 5, along a second radial section plane. [0024] [Fig. 7] shows schematically in section, part of a variant of the second example of an engine support device, according to an orthoradial section plane.

Description of the embodiments

Figure 1 illustrates a fan device 10 for a heating, ventilation and / or air conditioning installation for a motor vehicle. Conventionally, such a heating, ventilation and / or air conditioning installation for a motor vehicle comprises such a fan device 10, in a duct making it possible to guide an air flow created by the fan device 10 towards the passenger compartment of the vehicle. . Such a heating, ventilation and / or air conditioning installation may further comprise a device for heating the air flow, for example an electrical resistance or a heat exchanger, and / or a device for cooling the air flow, in particular a heat exchanger, placed between the fan device 10 and the outlet (s) of the heating installation, towards the passenger compartment.

As illustrated in Figure 1, the fan device 10 essentially comprises a fan wheel 12 and an electric motor 14 for driving the fan wheel 12 in rotation about its axis A. The fan device 10 also comprises a motor support 16 making it possible to assemble the electric motor 14 on a housing 18. Thus, the electric motor 14 is connected to the housing 18 by means of the motor support 16. The housing 18 can form part of the duct of the installation. heating, fan and / or air conditioning of the motor vehicle.

[0027] Hereinafter, the motor support 16 is described in more detail.

As visible in Figure 2, the motor support 16 comprises a first ring 20 or inner ring, a second ring 22 or outer ring, and a decoupling element 24, interposed between the inner ring 20 and the outer ring 22 The inner ring 20 is here intended to be fixed to the electric motor 14. The outer ring 22 is here intended to be fixed to the housing 18. The decoupling element 24 here has the form of a decoupling ring. The inner 20, outer 22 and decoupling 24 rings are here coaxial, with an axis common to the axis of rotation A of the fan wheel 12. The inner 20, outer 22 and decoupling 24 rings are here concentric.

The decoupling ring 24 is for example made of an elastomeric material, such as polystyrene-b-poly (ethylene-butylene) -b-polystyrene (or SEBS). The decoupling ring 24 is shaped so that the weight of the motor, mounted on the motor support 16 does not cause a displacement of one of the inner and outer rings 20, 22, relative to the other, greater than 0 , 5 mm, regardless of the direction in which the weight of the motor 14 exerts a force on the motor support 16.

Furthermore, the decoupling ring 24 forms four first pads 28i, identical, received in four housings 26 of the outer ring 22. The first pads 28i are regularly angularly distributed around the common axis A of the rings 20, 22 , 24. The first pads 28i are here integral with the decoupling ring 24. In this case, the first pads 28i make it possible to reinforce the decoupling ring 24, in particular in the direction of the axis A common to the rings 20, 22, 24. This reduces the risk of cracks appearing in the decoupling ring 24.

Furthermore, the inner ring 20 has radial projections 27, extending radially in the direction of the outer ring 22. Each radial projection 27 is received in an associated housing 26, formed by the outer ring 22.

In the following, we describe the example of the housing 26 visible in Figures 2 and 3, the outer ring 22 shown in Figure 2 having four identical housings 26.

The housing 26 is of substantially parallelepipedal shape. The housing 26 is thus defined by two walls 26i, 262 normal to the axis A common to the rings 20, 22, and two side walls which extend essentially in a radial direction and in an axial direction, parallel to the direction of the 'common axis A of the rings 20, 22, 24. Two tabs 29 protrude from the side walls of the housing 26. The tabs 29 thus extend towards the interior of the housing 26. The tabs 29 form a stop against the axial displacement of the radial projection 27 extending in the housing 26, in the event of displacement of one ring 20, 22, 24 relative to the other, in the direction of the common axis A of the rings 20, 22, 24.

As can be seen in Figures 2 and 3, a first pad 28i is received in the housing 26. The first pad 28i is sandwiched between the radial projection 27 and a wall 26i, here upper, of the housing 26, normal to the common axis A of the rings 20, 22, 24. The wall 26i of the housing 26 is here normal to the direction of the common axis A of the rings 20, 22, 24. In other words, in the direction of the common axis A of the rings 20, 22, 24, the first stud 28i extends at least in part between the radial projection 27 and the wall 26i of the housing 26, formed by the outer ring 22.

The first stud 28i is adapted to be stressed in compression, in the direction of the common axis A of the rings 20, 22. In particular, the first stud 28i is adapted to a stress in compression, in the event of approach of the rings inner and outer ring 20, 22 in the direction of the common axis A of the rings 20, 22. Here, such an approximation of the inner and outer rings 20, 22 corresponds to an upward movement of the inner ring 20 in FIG. 3 and / or a downward movement of the outer ring 22 in Figure 3.

The first pad 28i is for example made of a polymer material, for example SEBS.

The first pad 28i is cylindrical, preferably with a round or rectangular section. The first stud 28i has a height H, measured in the direction of the common axis A of the rings 20, 22, 24, which may be greater than or equal to 11 mm and / or less than or equal to 15 mm. The first pad 28i has a width B, measured in a radial direction relative to the common axis A of the rings 20, 22, 24, which may be greater than or equal to 8 mm and / or less than or equal to 15 mm. The first stud 28i has a length L, measured in an orthoradial direction with respect to the common axis A of the rings 20, 22, 24 which may be greater than or equal to 11 mm and / or less than or equal to 15 mm.

A cylindrical cavity 36 is formed in the first pad 28i. The cavity 36 is for example of circular or rectangular cross section. Here, the cavity 36 extends in a direction parallel to the direction of the common axis A of the rings 20, 22, 24. The cavity 36 extends over a depth P, measured in a direction parallel to the common axis A of the rings 20, 22, 24, which may be greater than or equal to 50% and / or less or equal to 95%, of the height H of the first pad 28i. The depth P of each cavity 36 can also be substantially equal to the height H of the first pad 28i. The cavity 36 also has a diameter D, which may be greater than or equal to 1.1 mm and / or less than or equal to 1.5 mm.

The cavity 36 is advantageously filled with rheo-thickening non-Newtonian fluid.

By rheo-thickening non-Newtonian fluid (or dilating non-Newtonian fluid) is meant here a fluid whose viscosity increases when the shear rate which is applied to it increases, with a flow curve, giving the viscosity as a function the stress velocity gradient, which curves upward, as the stress velocity gradient increases.

Thus, under low stress - that is to say under stress at a low speed gradient - the non-Newtonian fluid filling the cavity 36 retains a low viscosity. In this case, the first pad 28i retains considerable flexibility, allowing it to filter the vibration harmonics. Such a low stress corresponds for example to the stresses on the decoupling ring 24, due to the vibrations caused by the motor 14.

On the other hand, under a higher stress - that is to say a stress corresponding to a high speed gradient - the non-Newtonian fluid in the cavity 36 has a higher viscosity. This makes it possible to protect the decoupling ring 24 and the wheel 12 from possible deterioration, in particular in the case of a point stress, for example under the effect of an impact undergone by the vehicle, for example during a crossing over a bump or pothole.

The rheo-thickening non-Newtonian fluid may for example have a viscosity close to that of a Newtonian liquid, in the absence of stress or in the event of low contrary. By Newtonian liquid is meant a fluid which has no form of its own, in particular when it is not stressed. On the contrary, the rheo-thickening non-Newtonian fluid can have a behavior close to that of a solid, in case of high stress. By “to have a behavior of solid”, one understands to have a clean form.

An aqueous solution of polyvinyl alcohol and borax (or "slime"), a fluid of the brand D3o ® or an aqueous solution of corn starch are examples of rheo-thickening non-Newtonian fluid, having a viscosity if low, low stress, that they behave as a liquid that does not have its own shape. These examples are thus particularly suitable for filling the cavity 36.

The configuration of Figure 3 appears particularly interesting. In fact, the rheo-thickening non-Newtonian fluid is particularly susceptible to variations in viscosity, in the event of variations in compressive stresses. In addition, due to the cylindrical shape of the cavity 36, the inertia of the fluid contained therein is higher in the direction of the common axis A. It is therefore advantageous to apply the rheo-thickening non-Newtonian fluid according to the direction of the common axis A of the two rings 20, 22, between the radial projection 27 and the wall 26i of the housing 26.

The first pad 28i is preferably in contact with at least one of the radial projection 27 and the wall 26i of the associated housing 26. Preferably, the first stud 28i extends entirely between the radial projection 27 and the wall 26i of the housing 26. In other words, the first and second end faces 42, 44 of the first stud 28i, normal to the direction of the common axis A of the rings 20, 22, are fully covered by the radial projection 27 and the outer ring 22, respectively.

More preferably, the first stud 28i is in contact with each of the radial projection 27 and the wall 26i of the housing 26. The first stud 28i can in particular be fixed on its first and second end faces 42, 44 , to the radial projection 27 and to the wall 26i of the housing 26, respectively, in particular by overmolding, clipping or gluing.

In addition, as visible in Figure 2, the radial projection 27 can form a recess adapted to receive the first pad 28i. The first pad 28i can thus be wedged and the relative movements of the first pad 28i with respect to the radial projection 27, in particular in an orthoradial direction, are limited or even prevented. Figure 4 schematically illustrates a sectional view of a variant of the motor support 16 of Figures 2 and 3.

Figure 4 illustrates a configuration symmetrical to the configuration of Figure 3, in that a second stud 282 is sandwiched there between a radial projection 27 and a wall 262, here lower, of the housing 26, normal to the axis A of the rings 20, 22, 24. Thus, in the direction of the common axis A of the rings 20, 22, 24, the second stud 282 extends at least in part between the radial projection 27 and the lower wall 262 of the housing 26, preferably in contact with at least one of the radial projection 27 and the lower wall 262 of the housing 26.

Like the first pad 28i, the second pad 282 is adapted to be stressed in compression, in the direction of the common axis A of the rings 20, 22. Here, however, the second pad 282 is adapted to be stressed in compression, in case of movement of the inner ring 20 downwards in Figure 4 and / or in case of movement of the outer ring 22 upwards in Figure 4.

Advantageously, there may be provided between the two coaxial rings 20, 22, a plurality of first and second pads 28i, 282 as described above. In this case, the radial projections 27 and the housings 26 associated with the first and second pads 28i, 282 are shaped so that in the event of movement of one ring 20, 22 relative to the other 22, 20, only the first pads 28 where only the second pads 282 are compressed.

The decoupling element can in particular comprise four or six pads 28i, 282, or even more. The pads 28i, 282 are advantageously regularly distributed around the common axis A of the rings 20, 22. Even more advantageously, the plurality of pads 28i, 282 comprises as many first pads 28i as second pads 282, which are arranged alternately around the common axis A of the two rings 20, 22, a first pad 28i having two second pads 282 as closest neighbors and vice versa.

Figures 5 and 6 schematically illustrate a variant of Figures 3 and 4, respectively.

In these figures, the pads 28i, 282 are sandwiched, each time between, on the one hand, a first radial projection 38, formed by the inner ring 20 and extending radially towards the outer ring 22, and, on the other hand, a second radial projection 40, formed by the outer ring 22 and extending radially towards the inner ring 20. However, in Figure 5, the first radial projection 38 is disposed above the first pad 28i, while the second radial projection 40 is disposed below the first pad 28i. On the contrary, in FIG. 6, the first radial projection 38 is arranged below the first pad 28i, while the second radial projection 40 is arranged above the first pad 28i. Thus, whatever the relative movement of the inner ring 20 with respect to the outer ring 22, only one of the first pad 28i and the second pad 282 is stressed in compression.

Again, advantageously, the decoupling element comprises a plurality of pads 28i, 282, regularly distributed angularly around the common axis A of the rings 20, 22, 24. The plurality of pads 28i, 282 preferably comprises as many first pads 28i as second pads 282, the first and second pads 28i, 282 being arranged alternately around the common axis A of the rings 20, 22, 24.

Figure 7 illustrates a variant of the decoupling element 24 illustrated by Figures 5 and 6. Here, the opening 46 through the first radial projection 38 or the second radial projection 40, comprises a flared portion 48, preferably frustoconical. The portion 48 of the opening 46 is of increasing section from the first transverse surface 42 of the stud 28, towards the free surface of the radial projection 38, 40. Here, the smallest section of the opening 46 is identical to the section. of the cavity 36. The smaller section of the opening 46 is further placed opposite the cavity 36. The portion 48 thus facilitates the filling of the cavity 36 with rheo-thickening non-Newtonian fluid.

In order to guide the rheo-thickening non-Newtonian fluid towards the cavity 36, the stud 28 here forms a rim 52. The rim 52 matches the shape of the wall of the opening 46.

According to the example illustrated in Figure 7, a second portion 50 of the opening 46 is cylindrical. The second portion 50 is of substantially larger diameter than the diameter of the outlet of the frustoconical portion 48. The second portion 50 can thus receive a seal. Following the filling of the cavity 36 with rheo-thickening non-Newtonian fluid, a plug 54 is here received in the opening 46 to close the cavity 36 and the opening 46. The plug 54 can be fixed on the radial projection 38 , 40 by any suitable securing means, accessible to those skilled in the art. In the example illustrated, the stopper 54 is fixed to the projection 38, 40 by riveting or snap-fastening, two rods 56, passing through an edge of the stopper 54, being deformed after the installation of the stopper 54. The stopper 54 in place can compress the seal against the protrusion 38, 40.

The invention is not limited to the examples presented above but is on the contrary susceptible of numerous variations accessible to those skilled in the art.

[0062] In particular, the decoupling means 24 can take other forms than that of a decoupling ring. The pads 28i, 282 can in particular be separated. [0063] The rheo-thickening non-Newtonian fluid can also have its own shape, in particular in the absence of stress. D3o ® brand materials, for example, are such rheo-thickening non-Newtonian fluids having a specific shape, especially in the absence of stress. It may then be possible to make the decoupling pads 28i, 282 between the inner and outer rings 20, 22, or even the decoupling ring 24, entirely in such a material, or to replace the elastomeric material used in the examples described. previously by such a material.

Claims

[Claim 1] Motor support (16), in particular for a motor-fan unit (10) of a heating, ventilation and / or air conditioning installation of a vehicle, comprising:

- two coaxial rings (20; 22) of which a first ring (20) is able to receive one or more elements of an electric motor (14) and a second ring (22) is able to be fixed on a housing (18) intended to form a structural element, and

- a decoupling element (24) interposed between the first ring (20) and the second ring (22), the decoupling element (24) being made in whole or in part in rheo-thickening non-Newtonian fluid.

[Claim 2] An engine mount according to claim 1, wherein the shearthickening non-Newtonian fluid has its own shape in the absence of stress.

[Claim 3] An engine mount according to claim 1 or 2, wherein the decoupling element (24) comprises at least one stud (28i; 282), disposed between the first ring (20) and the second ring (22) , the pad (28i; 282), preferably defining a cavity (36) receiving rheo-thickening non-Newtonian fluid, the at least one pad (28i; 282) being, more preferably, sandwiched in the direction of l 'axis (A) of the two coaxial rings (20; 22) between a part (27; 38) of the first ring (20) and a part (26i; 262; 40) of the second ring (22).

[Claim 4] A motor support according to claim 3, in which the stud (28i; 282) is made of an elastomeric material, for example of SEBS, or of a rheo-thickening non-Newtonian fluid having a specific shape in the absence of stress.

[Claim 5] An engine mount according to claim 3 or 4, wherein the first ring (20) has a radial protrusion (27), the second ring (22) has a housing (26), the radial protrusion (27) being received in the housing (26), the stud (28i) being received at least partially in the housing (26), sandwiched, in the direction of the axis (A) common to the two coaxial rings (20, 22), between the radial projection (27) and a wall (26i) of the housing (26), normal to the common axis (A) of the two coaxial rings (20, 22).

[Claim 6] An engine mount according to claim 5, wherein the first ring (20) comprises at least one second radial projection (27), the second ring (22) has at least one second housing (26), the second projection (27) radial being received in the second housing (26), a second stud (282) being received at least partially in the second housing (26), in sandwich, in the direction of the axis (A) common to the two rings coaxial (20, 22), between the second radial projection (27) and a second wall (262) of the second housing (26), normal to the common axis (A) of the two coaxial rings (20, 22), the first and second radial projections (27) and the first and second walls (26i; 262) being shaped so that in the event of movement of one ring (20, 22) relative to the other ring (20, 22), the 'only one of said pad (28i) and the second pad (282) is compressed.

[Claim 7] An engine mount according to claim 5 or 6, wherein the stud (28i) and / or the second stud (282), if applicable, defines a cavity (36) receiving rheo-thickening non-Newtonian fluid, the second ring (22) and / or the first ring (20) comprising an opening (46) opening into the housing (26), making it possible to fill the cavity (36) with rheo-thickening non-Newtonian fluid.

[Claim 8] An engine mount according to claim 7, further comprising a plug (54) closing the cavity (36) and / or the opening (46), if any, preferably in a non-Newtonian fluid-tight manner. rheo-thickening.

[Claim 9] An engine mount according to any preceding claim, wherein the two coaxial rings (20, 22) are concentric, a first ring or inner ring (20) being disposed radially within a second. ring or outer ring (22).

[Claim 10] Motor-fan unit (10) for a vehicle heating, ventilation and / or air conditioning installation, comprising an electric motor (14), a fan wheel (12), driven in rotation by the electric motor (14) , and an engine mount (16) according to any preceding claim, the engine (14) being secured to one of the rings (20, 22) of the engine mount (16).