FR2904075A1 - Hydraulic anti-vibration support for use as e.g. engine support, has elastomer member including slot that is partially closed with pre-tensioning of member with respect to initial configuration of slot before encasing member in outer frame - Google Patents

Abstract

The support has an outer frame surrounding an inner frame (2), and an elastomer member (3) surrounding the inner frame and encased in the outer frame. An intermediate frame angularly extends between two lateral ends below 360 degrees around a central axis (X). The member includes a slot (13) provided near one of the ends and delimits two hydraulic chambers (A1, B1), which are connected to each other by a restricted passage (C1). The slot is partially closed with pre-tensioning of the member with respect to an initial configuration of the slot before encasing the member in the outer frame. An independent claim is also included for a method for fabricating a hydraulic anti-vibration support.

Description

1 Hydraulic antivibration support, internal sleeve for such support

  and a method of manufacturing such a support. The present invention relates to hydraulic antivibration mounts, internal sleeves for such supports and methods of manufacturing such supports. More particularly, the invention relates to a hydraulic antivibration support comprising: - a rigid inner frame which extends longitudinally along a central axis, - an annular rigid outer frame which surrounds the inner frame, - an elastomeric body surrounding the frame and axially intermeshed in the outer frame, said elastomeric body delimiting at least first and second hydraulic chambers interconnected by a first constricted passage, said first and second hydraulic chambers and the first throttled passage being filled with liquid and being closed radially outwardly by the outer frame, the elastomer body being reinforced by at least a first intermediate reinforcement overmolded by said elastomeric body and disposed in the vicinity of an outer periphery of the elastomeric body to ensure a tight closure of the first and second cha hydraulic members by contact between said elastomeric body and the outer frame. EP-A-1 348 885 describes an example of such a sleeve, which gives complete satisfaction. The present invention aims to further improve the antivibration sleeves of the aforementioned type, in particular to improve their life. For this purpose, according to the invention, an antivibration sleeve of the kind in question is characterized in that 2904075 2 that the first intermediate armature extends angularly less than 360 degrees about the central axis, between two lateral ends, and the elastomer body has at least one first slot in the vicinity of at least one of the lateral ends of the first intermediate frame, said first slot being at least partially closed (with prestressing of the elastomer body) with respect to a configuration initial of this first slot before 10 interlocking elastomer body in the outer frame. Thanks to these provisions, the compression prestress imposed on at least a portion of the elastomeric body during the engagement of said elastomeric body 15 in the outer frame, contributes to increasing the life of the antivibration support. In addition, the radial deformation of the elastomer body by compression during its engagement in the outer reinforcement is facilitated and better controlled, which makes it possible to facilitate this interlocking and to better control the tightness of the contact between the elastomer body. and the outer frame. This provides a tight and reliable closure of the hydraulic chambers of the sleeve, without the need to use plastic deformation techniques - moreover sometimes impossible with some sleeves - such as a narrowing of the outer frame or expansion of the inner frame. In preferred embodiments of the invention, one or more of the following provisions may also be used: the antivibration support further comprises a second intermediate reinforcement overmolded by said body; elastomer and arranged in the vicinity of the outer armature to ensure a tight closure of the first and second hydraulic chambers by contact between said elastomeric body and the outer armature, the second intermediate armature extending angularly over less than 360 degrees around the central axis between two lateral ends and the elastomeric body having a second slot, the first and second slots being disposed between the respective lateral ends of the first and second intermediate frames, said second slot being at least partially closed (with preload of the elastomer body) compared to an initial configuration of this second slot before interlocking of the elastomer body in the outer frame; the first and second intermediate armatures are substantially diametrically opposite with respect to the central axis; The first and second slots extend substantially radially with respect to the central axis and open radially outwards; each of the first and second intermediate armatures comprises two arches axially flanking the hydraulic chambers and extending angularly about the central axis between two lateral spacers extending substantially axially respectively at the two lateral ends of said first and second intermediate armatures; ; Each of the first and second intermediate armatures further comprises a central spacer which extends substantially axially between the two arches, the elastomer body further comprising first and second elastomeric arms which extend substantially radially up to the outer armature overmolding respectively said central struts of the first and second intermediate armatures, at least the first arm separating the first and second hydraulic chambers and said first and second arm being compressed radially by the outer armature; 2904075 4 - the first throttled passage is formed between the first arm and the outer armature; the elastomer body further delimits third and fourth hydraulic chambers connected between them by a second constricted passage, said third and fourth hydraulic chambers and the second constricted passage being filled with liquid and being closed radially outwards by the outer armature, and said third and fourth hydraulic chambers being separated by the second arm; the second throttled passage is formed between the second arm and the outer armature; the first and second arms are substantially diametrically opposed with respect to the central axis; The elastomer body further comprises third and fourth elastomer arms in which are formed the first and second slots and which extend substantially radially to the outer frame, each of which overmold one of the lateral struts of the elastomer; the first intermediate armature and one of the lateral spacers of the second intermediate armature, the fourth arm separating the first and third hydraulic chambers and the third arm separating the second and fourth hydraulic chambers; The fourth arm separates the first and third hydraulic chambers in a sealed manner and the third arm separates the second and fourth hydraulic chambers in a sealed manner; the first and second slots are substantially closed. Furthermore, the invention also relates to an inner sleeve for a hydraulic antivibration support as defined above, this inner sleeve comprising: a rigid inner armature which extends longitudinally along a central axis, and an elastomeric body surrounding the inner armature and intended to be fitted axially in an annular outer armature which surrounds the inner armature, this elastomeric body delimiting at least first and second chambers interconnected by a first throttled passage, said first and second hydraulic chambers and the constricted passage being intended to be filled with liquid and to be closed radially outwardly by the outer reinforcement, the elastomeric body being reinforced by at least a first intermediate reinforcement overmolded by said elastomeric body. and disposed in the vicinity of an outer periphery of the body elastomer (for sealing the first and second chambers by contact between said elastomeric body and the outer armature), characterized in that the first intermediate armature extends angularly less than 360 degrees about the central axis between two lateral ends, leaving a non-reinforced zone of the elastomer body free, and in that the elastomeric body has at least one first slot open in the vicinity of at least one of the lateral ends of the intermediate reinforcement. In various embodiments of the inner sleeve 25 according to the invention, one or more of the following provisions may also be used: the inner sleeve further comprises a second intermediate reinforcement overmolded by said elastomer body and disposed in the vicinity of the outer periphery of the elastomer body (to ensure a sealed closure of the first and second chambers by contact between said elastomeric body and the outer frame), the second intermediate armature extending angularly on less than 360 degrees about the central axis 35 between two lateral ends and the elastomeric body having a second open slot, the first and second slots being disposed between the lateral ends respectively of the first and second intermediate frames; The first and second slots extend substantially radially with respect to the central axis and open radially outwards; each of the first and second intermediate armatures comprises two arches axially surrounding the chambers and extending angularly about the central axis between two lateral spacers extending substantially axially respectively at the two lateral ends of said first and second intermediate armatures; Each of the first and second intermediate armatures further comprises a central spacer which extends substantially axially between the two arches, the elastomer body further comprising first and second elastomer arms which extend substantially radially by overmolding respectively said central struts of the first and second intermediate frames, at least the first arm separating the first and second chambers; the first constricted passage is formed in an outer surface of the first arm; the elastomer body further defines third and fourth chambers interconnected by a second constricted passage, said third and fourth chambers and the second constricted passage being intended to be filled with liquid and to be closed radially outwards by the outer armature, and said third and fourth chambers being separated by the second arm; the second throttled passage is formed in an outer surface of the second arm; The elastomer body further comprises third and fourth elastomeric arms in which are formed the first and second slots and which extend substantially radially by each overmolding one of the lateral spacers of the first intermediate armature and one of the lateral struts of the second intermediate armature, the fourth arm separating the first and third chambers and the third arm separating the second and fourth chambers.

Finally, another subject of the invention is a method of manufacturing an antivibration support as defined above, comprising the following steps: (a) manufacture of an internal sleeve as defined above, (b) ) interlocking said inner sleeve in an annular outer frame by simultaneously compressing the elastomeric body so as to close at least partially said first slot. Optionally, the interlocking step (b) can be performed in a liquid bath so that the hydraulic chambers and the constricted passage (s) are simultaneously filled with liquid. When the inner sleeve has two intermediate reinforcements and two slots, the elastomer body is compressed by bringing the first and second intermediate reinforcements closer to each other during step (b), at least partially closing the two slots. Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings. In the drawings: FIG. 1 is a perspective view of a hydraulic antivibration support according to one embodiment of the invention; FIG. 2 is a view in axial section of the antivibration support of FIG. 1, the section being taken along line II-II of FIG. 3, FIG. 3 is a radial sectional view of the antivibration support of FIGS. 1 and 2, the section being taken along the line III - III of FIG. 2, FIG. 4 is an exploded perspective view showing only the metal parts of the antivibration support of FIGS. 1 to 4; FIG. 5 is a perspective view of an internal sleeve belonging to the antivibration support of FIGS. 1 to 4; FIG. 6 is an axial sectional view of the inner sleeve of FIG. 5, the section being taken along the line VI-VI of FIG. 7; FIG. 7 is a radial sectional view of the inner sleeve of FIGS. 6, the section being taken along the line VII-VII of FIG. 6, and Figure 8 is a perspective view of an intermediate frame according to an alternative embodiment.

In the figures, the same references designate identical or similar elements. FIG. 1 shows a hydraulic antivibration support which has a generally cylindrical general shape with a central axis X, intended for example to constitute an antivibration joint, serving as an engine support, a vehicle suspension support, a vehicle body support or the like . As can be seen in FIGS. 1 and 2, the antivibration support 1 comprises: a rigid inner armature 2 which extends longitudinally along the central axis X, this inner armature 2 being able to be formed for example by a metal part tubular, of revolution or not about the axis X or about an axis parallel to the axis X, 35 - an elastomeric body 3 surrounding the inner armature 2 radially outwardly and being able for example overmolded and bonded to said inner frame, said elastomeric body being made of, for example, natural or synthetic rubber, the elastomer body 3 is the inner frame 2 together forming an inner sleeve 4, 5 - and an outer frame 5 of generally cylindrical general shape of axis X, wherein the elastomer body 3 is axially engaged, said outer armature 5 can be made for example in the form of a piece of metal sheet and may be overmolded if necessary with an elastomer layer 6. As can be seen in FIGS. 2 and 3, the elastomer body 3 delimits at least two hydraulic chambers interconnected by a constricted passage and in the example considered here, the elastomer body 3 defines four hydraulic chambers, namely: first and second hydraulic chambers A1, B1 interconnected by a first constricted passage Cl and arranged in opposition to each other in a direction Y1 perpendicular to the aforementioned central axis X 20, and third and fourth hydraulic chambers A2, B2 communicating with each other by a second constricted passage C2 and disposed in mutual opposition in said radial direction Y1.

The first and second hydraulic chambers A1, B1 and the first constricted passage C1 are filled with liquid and form a first hydraulic network, while the third and fourth hydraulic chambers A2, B2 and the second constricted passage C2 are filled with liquid 30 and form a second hydraulic network isolated from the first hydraulic network mentioned above. Each of these hydraulic networks is sealed: axially and radially inwards by the elastomer body 3 and radially outwardly by the outer armature 5.

More specifically, these two hydraulic networks are axially closed by two solid annular portions 7, 8 of the elastomer body (see FIG. 5) disposed at the axial ends of said elastomeric body and in radial sealing contact with the inner surface. 5. Furthermore, the elastomer body 3 comprises first and second elastomer arms 9, 10 (see FIGS. 2, 3 and 5) which are substantially diametrically opposed with respect to the X axis and which extend radially outwardly from the inner armature 2 until contact with the inner surface of the outer armature 5, these first and second elastomeric arms 9, 10 being radially compressed by the outer armature 5. Each First and second elastomeric arms 9, 10 extend substantially parallel to a plane defined by the X axis and by an axis Y 2 perpendicular to the above-mentioned X, Y 1 axes, between the two annular portions 7, 8 mentioned above. The first elastomeric arm 9 separates the first 20 and second hydraulic chambers A1, B1 and has a groove C1 hollowed in its radially outer surface. This groove Cl extends angularly between the hydraulic chambers A1, B1 and forms the first constricted passage which communicates with said first 25 and second hydraulic chamber A1, B1. Similarly, the second elastomeric arm 10 separates the third and fourth hydraulic chambers A2, B2 and has a groove C2 hollowed in its radially outer surface. This groove C2 extends angularly between the hydraulic chambers A2, B2 and forms the second throttled passage which communicates with said third and fourth hydraulic chambers A2, B2. The elastomeric body 3 further comprises third and fourth elastomeric arms 11, 12, 13 which are substantially diametrically opposed with respect to the X axis and which extend radially outwardly from the outer frame 2 to the contact of the inner surface of the outer armature 5. The third and fourth elastomeric arms 11, 12 extend substantially parallel to a plane defined by the X and Y1 axes between the two annular portions 7. , 8 mentioned above of the elastomer body. The third elastomeric arm 11 sealingly separates the second hydraulic chamber B1 from the fourth hydraulic chamber B2, while the fourth elastomeric arm 12 sealingly separates the first hydraulic chamber A1 from the third hydraulic chamber A2. As shown in FIGS. 2 to 4, the elastomer body 3 is reinforced by first and second intermediate armatures 15, 16 which can be made, for example each, of a single piece, in cut sheet metal and stamped and which are overmolded. by the elastomer body. Each of these intermediate armatures 15, 16 has a shape that can be cylindrical, for example, and extends angularly about 180 around the central axis X. The intermediate armatures 15, 16 are here diametrically opposite in the direction Y2. More particularly, in the example shown, each of the intermediate armatures comprises two arcuate arches, respectively 16, 19 and 18, 20, 25 which extend angularly about the axis X between two lateral ends. These lateral ends are formed here by two lateral spacers, respectively 21, 22, extending axially between the two aforementioned hoops. In addition, in the example considered here, each of the intermediate armatures 15, 16 further comprises a central spacer, respectively 23, 24 which extends axially between the two arches, respectively 16, 19 and 18, 20 of the two armatures intermediate. The arches 16, 18 are arranged at the level of the solid annular portion 7 of the elastomer body, in the vicinity of the outer periphery of the elastomer body, so as to reinforce said annular portion 2904075 12 full to improve the sealing of the contact between said solid portion 7 and the outer armature 5. Likewise, the arches 19, 20 are overmolded by the solid annular portion 8 of the elastomer body and are arranged in the vicinity of the outer periphery of this solid portion 8 of in order to reinforce it and to ensure a sealed contact of said solid portion 8 with the outer reinforcement 5. Moreover, the central struts 23, 24 are overmolded respectively by the first and second elastomeric arms 9, 10. the third and fourth arms 11, 12 are each overmolded on a lateral spacer 21 of the first intermediate reinforcement 15 and on a lateral spacer 22 of the two The third and fourth arms 11, 12 respectively comprise slots 13, 14 which are interposed between the respective lateral spacers 21, 22 of the first and second intermediate armatures. In the example 20 considered here, the slots 13, 14, extend radially in the direction Y1 and open radially outwards against the inner surface of the outer frame 5. When the inner sleeve 4 is fitted into 25 5, the slots 13, 14 are at least partially closed and the lateral spacers 19, 21 of the first and second intermediate armatures are brought closer to one another at each of the third and fourth elastomeric arms 11, 12, with respect to the configuration of the inner sleeve 4 before engagement (see FIG. 7), while the first and second elastomer arms 9, 10 are compressed radially. In the particular example shown in the drawings, the slots 13, 14 are substantially closed and the side spacers 21, 22 are in the immediate vicinity of each other within each of the third and fourth elastomeric arms. 11, 12, when the inner sleeve 4 is fitted into the outer armature 5. In the method of manufacturing the antivibration support described above, the first embodiment is to manufacture separately, on the one hand, the inner sleeve 4 (see FIGS. 5 to 7) and, on the other hand, the outer armature 5. As can be seen in particular in Figures 5 and 7, the slots 13, 14 of the inner sleeve 4 are then open, the lateral spacers 21, 22 Respectively belonging to the third and fourth elastomeric arms 11, 12 are spaced from each other, and the first and second arm 9, 10 are not compressed radially. The inner sleeve 4 is fitted axially into the outer frame 5, simultaneously compressing the elastomer body 3 in the direction Y2 so as to close at least partially the slots 13, 14. This nesting step is generally performed within a liquid bath so that the hydraulic chambers A1, B1, A2, B2, and the constricted passages C1, C2 are simultaneously filled with liquid. Thanks to the presence of the slots 13, 14, and the presence of the two intermediate plates 15, 16, the radial deformation of the elastomer body 3 is controlled in a controlled manner, without risk of buckling of the arches 17, 18, 19, 20 intermediate reinforcement, which facilitates this interlocking and better control the sealing of the contact between the elastomeric body 3 and the outer frame 5 after interlocking.

Note that if appropriate, the antivibration support may comprise a single intermediate armature 115 extending for less than 360 degrees about the X axis, and a single slot 113 formed in one of the arms 11, 12 between the two side ends of this intermediate armature, as in the variant shown in Figure 8. In this variant, will be described hereinafter only the intermediate armature, the other parts of the sleeve being identical to those described above if is only the slot 13 is removed. In the particular example shown in FIG. 8, the intermediate reinforcement 115 has a shape that can be cylindrical, for example, and extends angularly about 350 around the central axis X. More particularly, in the example represented the intermediate reinforcement comprises two arcuate arches 116, 119, which extend angularly about the X axis between two lateral ends. These lateral ends are formed here by two lateral spacers, respectively 121, 122, extending axially between the two aforementioned hoops. The lateral struts 121, 122 are substantially diametrically opposed with respect to a median strut 120 which also connects the arches 116, 119. In addition, in the example considered here, the intermediate reinforcement 115 further comprises two central struts, respectively 123, 124 which extend axially between the two arches 116, 119 of the two intermediate plates, one between the spacers 120, 121, and the other between the spacers 120, 122. The arch 116 is disposed at the solid annular portion 7 of the elastomer body, in the vicinity of the outer periphery of the elastomeric body, so as to reinforce said solid annular portion 7 to improve the sealing of the contact between said solid portion 7 and the outer armature 5 Likewise, the hoop 119 is overmolded by the solid annular portion 8 of the elastomer body and is disposed in the vicinity of the outer periphery of this portion. n full 8 so as to strengthen and ensure a sealed contact of said solid portion 8 with the outer frame 5.

Furthermore, the central struts 123, 124 are overmoulded respectively by the first and second elastomeric arms 9, 10. In addition, the third arm 11 has no slot 13 and is overmolded on the central strut 120, while the fourth arm 12 is overmolded on the side struts 121, 122, the slot 14 of the fourth arm passing between said lateral struts 121, 122. In this case, the intermediate armature deforms in flexion during the nesting of the internal sleeve 4 in the outer frame 5, closing the slot 14 mentioned above.

It will be noted moreover that, the first and second elastomeric arms 9, 10, which work shear during the use of the antivibration support, are put in compression prestressing during the interlocking, which avoids or limits the appearance tensile stresses 15 during the use of the antivibration support and therefore increases the service life of this support. The antivibration support 1 which has just been described operates as follows. When the inner and outer armatures 5 and 20 are subjected to relative vibratory movements in the Y1 direction, these movements cause liquid to be displaced on the one hand between the first and second hydraulic chambers A1, B1 through the first constricted passage C1 and on the other hand between the third and fourth hydraulic chambers A2, B2, through the second throttled passage C2. This results in a damping of these vibratory movements, as well as a relative insulation between the inner and outer armatures 5, which are particularly effective for frequencies close to a resonance frequency depending on the vibrations of each of the choked passages C1, C2 (If the constricted passages C1, C2 are of different geometry, each of the hydraulic networks may optionally have its own resonant frequency). Note that, since the two hydraulic networks, A1, B1, C1 and A2, B2, C2 are independent of each other, an accidental leak occurring on one of these hydraulic networks allows the support antivibration to retain at least some of its damping and insulation characteristics.

On the other hand, it should be noted that the grooves delimiting the constricted passages C1, C2, instead of being simply molded into the elastomeric body, could be: - either formed by plastic inserts overmolded by the elastomeric body, - Delimited by stamped portions of the central spacers 23, 24 of the intermediate frames.

Claims (24)

  1. Hydraulic antivibration support comprising: - a rigid inner armature (2) extending longitudinally along a central axis (X), - an annular rigid outer armature (5) which surrounds the inner armature (2), - a elastomer body (3) surrounding the inner armature (2) and fitted axially in the outer armature (5), said elastomeric body delimiting at least first and second hydraulic chambers (Al, Bl) interconnected by a first constricted passage (C1), said first and second hydraulic chambers (A1, B1) and the first constricted passage (C1) being filled with liquid and being radially outwardly closed by the outer armature (5), the body elastomer (3) being reinforced by at least a first intermediate reinforcement (15) overmolded by said elastomer body (3) and disposed in the vicinity of an outer periphery of the elastomeric body 20 to provide a closure sealing of the first and second hydraulic chambers (Al, Bl) by contact between said elastomer body (3) and the outer armature (5), characterized in that the first intermediate armature (15) extends angularly over less than 360 degrees about the central axis (X), between two lateral ends (21), and in that the elastomeric body has at least one first slot (13) in the vicinity of at least one of the lateral ends (21) of the first intermediate armature (15), said first slot (13) being at least partially closed with respect to an initial configuration of this first slot before engagement of the elastomer body (3) in the outer armature (5). 35   2. Antivibration support according to claim 1, 2904075 18 further comprising a second intermediate frame (16) overmolded by said elastomer body (3) and disposed in the vicinity of an outer periphery of the elastomer body to ensure a tight closure of the first and second hydraulic chambers (Al, B1) by contact between said elastomeric body (3) and the outer armature (5), the second intermediate armature (16) extending angularly less than 360 degrees about the central axis (X) between two lateral ends (22) and the elastomer body (3) having a second slot (14), the first and second slots being disposed between the respective lateral ends (21, 22) of the first and second intermediate frames ( 15, 16), said second slot (14) being at least partially closed with respect to an initial configuration of this second slot before interlocking with the body. stomere (3) in the outer frame (5).   3. Antivibration support according to claim 2, wherein the first and second intermediate armatures (15, 16) are substantially diametrically opposite with respect to the central axis (X).   4. Antivibration support according to claim 2 or claim 3, wherein the first and second slots (13, 14) extends substantially radially relative to the central axis (X) and open radially outwardly.   5. Antivibration support according to any one of claims 2 to 4, wherein each of the first and second intermediate armatures (15, 16) comprises two arches (17, 19; 18, 20) axially flanking the hydraulic chambers (Al, B1). ) and extending angularly about the central axis (X) between two lateral spacers (21; 22) extending substantially axially respectively at the two lateral ends of said first and second intermediate armatures (15, 16). 2904075 19   An antivibration support according to claim 5, wherein each of the first and second intermediate armatures (15, 16) further comprises a central spacer (23, 24) which extends substantially axially between the two arches (17, 19; 18, 20), the elastomer body (3) further comprising first and second elastomeric arms (9, 10) which extend substantially radially to the outer reinforcement (5) by respectively overmolding said central struts ( 23, 24) of the first and second intermediate armatures (15, 16), at least the first arm (9) separating the first and second hydraulic chambers (A1, B1) and said first and second arms (9, 10) being compressed radially by the outer frame (5). 15   7. Antivibration support according to claim 6, wherein the first constricted passage (Cl) is formed between the first arm (9) and the outer armature (5).   8. Antivibration support according to any one of claims 6 and 7, wherein the elastomeric body (3) further delimits third and fourth hydraulic chambers (A2, B2) interconnected by a second throttled passage (C2). said third and fourth hydraulic chambers and the second throttled passage being filled with liquid and being radially outwardly closed by the outer armature (5), and said third and fourth hydraulic chambers (A2, B2) being separated by the second arm (10).   An antivibration support according to claim 8, wherein the second throttled passage (C2) is provided between the second arm (10) and the outer armature (5).   10. Antivibration support according to any one of claims 6 to 9, wherein the first and second arm (9, 10) are substantially diametrically opposed relative to the central axis (X). 35   An antivibration mounts according to any one of claims 5 to 10, wherein the elastomeric body (3) further comprises third and fourth arms (11,   12) made of elastomer in which are formed the first and second slots (13, 14) and which extend substantially radially to the outer frame (5) by each overmolding one of the lateral struts (21) of the first intermediate reinforcement (15) and one of the lateral struts (22) of the second intermediate reinforcement (16), the fourth arm (12) separating the first and third hydraulic chambers (A1, A2) and the third arm (11). ) separating the second and fourth hydraulic chambers (B1, B2). 12. Antivibration support according to claim 11, wherein the fourth arm (12) separates the first 15 and third hydraulic chambers (A1, A2) in a sealed manner and the third arm (11) separates the second and fourth (B1, B2). hydraulic chambers in a sealed manner.   Antivibration mount according to any one of claims 2 to 12, wherein the first and second slots (13,   14) are substantially closed. 14. Inner sleeve (4) for a hydraulic antivibration support (1) according to any one of the preceding claims, the inner sleeve (4) comprising: 25 - a rigid inner armature (2) extending longitudinally along a central axis (X), and an elastomeric body (3) surrounding the inner armature (2) and intended to be fitted axially in an annular outer armature (5) which surrounds the inner armature (2), this elastomer body delimiting at least first and second chambers (A1, B1) interconnected by a first constricted passage (C1), said first and second chambers and the constricted passage being intended to be filled with liquid and to be closed radially towards the outside by the outer armature (5), the elastomeric body (3) being reinforced by at least a first intermediate armature (15) overmolded by said elastomeric body (3) and arranged in the vicinity of a the outer periphery of the elastomer body, characterized in that the first intermediate reinforcement (15) extends angularly less than 360 degrees about the central axis (X), between two lateral ends (21), leaving free an unreinforced zone of the elastomer body, and in that the elastomer body (3) comprises at least a first open slot (13) in the vicinity of at least one of the lateral ends (21) of the intermediate reinforcement . 15   15. Inner sleeve according to claim 14, further comprising a second intermediate reinforcement (16) overmolded by said elastomer body (3) and disposed in the vicinity of the outer periphery of the elastomer body, the second intermediate reinforcement (16) 20 extending angularly less than 360 degrees about the central axis (X) between two lateral ends (22) and the elastomeric body (3) having a second open slot (14), the first and second slots (13, 14 ) being disposed between the lateral ends (21; 22) 25 respectively of the first and second intermediate armatures (15,   16). Inner sleeve according to claim 15, wherein the first and second slots (13,14) extend substantially radially with respect to the central axis (X) and open radially outwardly.   An inner sleeve according to claim 15 or claim 16, wherein each of the first and second intermediate armatures (15, 16) comprises two arches (17, 19; 18, 20) axially flanking the chambers 35 and extending angularly around the central axis (X) 2904075 22 between two lateral struts (21, 22) extending substantially axially respectively at the two lateral ends of said first and second intermediate armatures (15, 16). 5   18. Inner sleeve according to claim 17, wherein each of the first and second intermediate armatures (15, 16) further comprises a central spacer (23, 24) which extends substantially axially between the two arches (17, 19; 20), the elastomeric body 10 (3) further comprising first and second elastomeric arms (9, 10) which extend substantially radially by respectively overmolding said central struts (23, 24) of the first and second intermediate reinforcements at least the first arm (9) separating the first and second chambers (Al, B1).   The inner sleeve of claim 18, wherein the first constricted passage (C1) is provided in an outer surface of the first arm (9).   20. An inner sleeve according to claim 18 or claim 19, wherein the elastomeric body (3) further defines third and fourth chambers (A2, B2) interconnected by a second constricted passage (C2), said third and fourth chambers and the second constricted passage intended to be filled with liquid and to be closed radially outwardly by the outer armature, and said third and fourth chambers being separated by the second arm (10).   21. The inner sleeve of claim 20, wherein the second constricted passage (C2) is provided in an outer surface of the second arm (10).   22. Inner sleeve according to any one of claims 18 to 21, wherein the elastomer body (3) further comprises third and fourth elastomeric arms (11, 12) in which the first and second slots ( 13, 14) and which extend substantially radially by each overmolding one of the lateral spacers (21) of the first intermediate reinforcement (15) and one of the lateral spacers (22) of the second intermediate reinforcement (16). ), the fourth arm (12) separating the first and third chambers (A1, A2) and the third arm (11) separating the second and fourth chambers (B1, B2).   23. A method of manufacturing an antivibration support according to any one of claims 1 to 13, comprising the following steps: (a) manufacturing an inner sleeve (4) according to any one of claims 14 to 22, (b) interlocking said inner sleeve (4) in an annular outer frame (5) by simultaneously compressing the elastomeric body (3) so as to at least partially close said first slot (13).   24.A method according to claim 23, wherein an inner sleeve (4) according to any one of claims 15 to 22 is used, and the elastomeric body (3) is compressed by bringing the first and second intermediate reinforcements (15) closer together. , 16) of each other during step (b), at least partially closing the two slots (13, 14).