CTIS SYSTEM SEALING ASSEMBLY

Abstract

A sealing group (1) is described for the hermetic sealing of an annular compartment (2) formed between a stator element (3) and a rotor element (4) and configured to allow the hermetic passage of a pressurized fluid between the stator element (3) and the rotor element (4) through the annular compartment (2), the sealing group (1) comprising: an annular support ring (13) configured to be shimmed on the stator element (3) and having an internal annular surface (13a) and an external annular surface (13b); a pair of annular sealing elements (10) arranged on axially opposite parts of the annular compartment (2) in order to seal, in a fluid-tight manner, the annular compartment (2);Each sealing element (10) comprises a support portion (11) configured to be coupled to the rotor element (4) in a manner fixed to the latter, and a sealing portion (12) positioned to abut in a fluid-tight manner against the external surface (13b) of the support ring (13) and adapted to slide on said external surface (13b), wherein the sealing group (1) comprises an annular retaining element (14) fixing the sealing elements (10) to each other and to the support ring (13) thus defining a set of parts removably coupled to each other. Main figure: [Fig 1];

Description

Title of the invention: Sealing assembly for CTIS system technical field

[0001] The present invention relates to a sealing group for the hermetic sealing of an annular compartment formed between a first stator element, in particular a support shaft of a wheel of a vehicle, and a second element, rotor with respect to the first element, for example a hub of this same wheel.

[0002] In particular, the sealing group is configured to allow the sealed passage of a fluid (for example, pressurized air) from a first environment to a second environment, located on either side of the aforementioned compartment, and furthermore to prevent the passage of contaminants (for example, lubricating oil) from an external environment to the compartment mentioned above.

[0003] In particular, the present invention relates to a sealing group of the type mentioned above, and in particular adapted to be implemented in a CTIS system (“Central Tire Inflating System”). State of the art

[0004] CTIS systems are known for use on vehicles operating in conditions involving frequent transitions between paved and unpaved roads, or at least rough roads, and vice versa (off-road vehicles, fire trucks, tractors, and the like). In particular, such systems allow for the pressurization and depressurization (inflation and deflation) of the tires during the movement of the aforementioned vehicles, according to the different terrain conditions.

[0005] In more detail, on asphalt surfaces, or at least relatively hard and relatively flat surfaces, it is necessary to maintain a tire pressure of around 8 to 10 bar, whereas on softer or rougher surfaces, for example on a dirt road, it is necessary to depressurize the tires to a pressure of around 2 bar. As specified above, this inflation and depressurization operation must take place simultaneously with the vehicle's movement.

[0006] For this purpose, the vehicles mentioned above are equipped with a circuit through which pressurized air circulates. In particular, the circuit is configured to supply pressurized air to the tires and to extract pressurized air from them. last. Typically, the circuit has as many branches as there are road bodies of the vehicle, including the tires to be powered.

[0007] In the following description, reference is made to a single branch of the circuit and to the relative wheel body, and what is described can be applied in the same way to each branch of the circuit and to each relative wheel body.

[0008] It is specified that with "wheel body", in the present description and for a single tire, we mean the assembly including the wheel support shaft, the wheel hub and all the components necessary for their mutual operation, such as bearings.

[0009] Each branch of the circuit typically comprises: a fixed part, which receives pressurized air from a source, for example a compressor, and extends inside the fixed part of the wheel body (shaft); a moving part, which receives pressurized air from the fixed part and extends inside the rotating part of the wheel body (hub); and an annular compartment formed between the wheel shaft and the relative hub, interposed, in a fluidic manner, between the fixed part and the moving part and connecting, in a fluidic manner, the fixed part to the moving part.

[0010] In order to hermetically seal the fluid connection between the fixed part and the moving part of the branch of the circuit, a sealing group is interposed in the annular compartment formed between the shaft and the hub.

[0011] Such a sealing group is configured to prevent the leakage of pressurized air from the circuit and simultaneously, the entry of external contaminants (for example, lubricant) into the circuit itself.

[0012] Commonly, the sealing groups used comprise two seals or gaskets interposed radially, with respect to the axis of the shaft (and therefore with respect to the axis of rotation of the hub) between the shaft and the hub and positioned in correspondence with the compartment mentioned above.

[0013] In detail, the two seals are arranged symmetrically with respect to the compartment itself, so as to have corresponding parts facing each other across the compartment.

[0014] Each seal is rotationally fixed to the wheel hub and comprises at least one sealing lip which, in order to seal a gap between fixed and moving components, operates under dynamic conditions. In practice, each sealing lip slides on the surface of the wheel shaft as the respective seal is rotated from the hub.

[0015] In this way, it is possible to achieve the fluid connection between the fixed part and the moving part of the circuit.

[0016] The applicant has observed how sealing groups of the type mentioned above are improved from the point of view of assembly and mounting on the relative wheel body.

[0017] In fact, in order to assemble a sealing unit of the type mentioned above onto the relevant wheel body, it is necessary at least to: precisely align the first seal (inner side of the wheel body) on its designated seat on the shaft, hold this first seal in position, precisely align the second seal (outer side of the wheel body) on its designated seat on the shaft, and hold this second seal in position. Such steps are particularly complicated to manage, taking into account the dimensions of the parts already in position and the assembly considerations, and also the fact that the alignment also provides support for the seals from the wheel hub.

[0018] In addition, other components are provided such as retaining rings (for example, Seeger rings), which must be perfectly positioned.

[0019] Among these components, other components can be provided such as wear or support rings and various sealing rings, such as for example an O-ring, considerably complicating the assembly of the sealing group and the mounting of the latter on the relative wheel body.

[0020] From the moment when the correct assembly of the seals and all the auxiliary components mentioned above is necessary to guarantee the nominal operation of the pressurization and depressurization circuit, it results in the need to simplify the architecture, reduce the number of components and simplify the assembly of the sealing groups of the known type. Object and summary of the invention

[0021] The object of the present invention is to produce a sealing group for CTIS systems, which must exhibit high reliability and have a limited cost, and make it possible to remedy at least some of the disadvantages specified above and related to known type sealing groups.

[0022] According to the invention, this goal is achieved by a sealing group, as claimed in claim 1. Brief description of the drawings

[0023] For a better understanding of the present invention, a preferred, non-limiting embodiment is described in the following section, simply by way of example and with reference to the accompanying drawings, in which:

[0024] [Fig. 1] [Fig. 1] is a cross-sectional perspective view of a sealing group made according to the present invention;

[0025] [Fig.2] [Fig.2] is a cross-sectional view of a wheel body of a vehicle defining an annular compartment, in which compartment is inserted the sealing group of [Fig.1];

[0026] [Fig. 3] [Fig. 3] is an enlarged view of the sealing group inserted into the wheel body; and

[0027] [Fig.4] [Fig.4] is an exploded perspective view of the sealing group of [Fig.1]. Detailed description

[0028] With reference to the attached figures, a sealing group arranged in correspondence with an annular compartment 2 formed between a stator element 3 and a rotor element 4 movable, relative to the stator element 3, according to a rotary movement around an axis A.

[0029] In particular, the stator element 3 is annular and defines the terminal part (or shaft) of an axle of a wheel of a vehicle; the rotor element 4 is also annular, defines the hub in relation to this wheel and extends radially further outside the stator element 3.

[0030] In particular, group 1 is suitable for implementation in a CTIS system of a vehicle and is configured to hermetically seal the fluid-tight compartment 2.

[0031] In detail, group 1 is configured to allow the sealed passage of a pressurized fluid, in this case pressurized air, through compartment 2. In more detail, the pressurized fluid circulates, in use, from a first environment 5 of a circuit (not illustrated) to a second environment 6 of the same circuit, and vice versa; these environments 5 and 6 are arranged on the radially opposite parts of compartment 2, respectively corresponding to the stator element 3 and the rotor element 4.

[0032] Therefore, group 1 is configured to allow the sealed passage of pressurized fluid between the stator element 3 and the rotor element 4 through compartment 2, and to prevent the passage of contaminants from an external environment into compartment 2.

[0033] The aforementioned circuit is configured to supply the pressurized fluid to environment 6 and vice versa, to selectively bring this fluid from environment 6 to environment 5.

[0034] For this purpose, the circuit comprises: a fixed part 7 arranged in correspondence with the environment 5, receiving, in use, the pressurized fluid from a source, for example a compressor, and extending inside the stator element 3; a movable part 8 arranged in correspondence with the environment 6, capable of rotating around the axis A, receiving, in use, the pressurized fluid from the fixed part 7, and extending inside the rotor element 4; and compartment 2, which is configured to connect, in a fluidic manner, the fixed part 7 to the moving part 8.

[0035] In detail, the fixed part 7, the moving part 8 and the compartment 2 house, in a constant manner, the pressurized fluid during use.

[0036] As indicated above, group 1 is also configured to prevent the passage of contaminants (e.g., lubricating oil) from an external environment 50 into compartment 2.

[0037] For such a purpose, group 1 comprises a pair of annular sealing elements or seals 10.

[0038] The seals 10 have an annular configuration around the axis A and are arranged (appropriately symmetrically) on axially opposite parts of compartment 2 in order to seal compartment 2 tightly against fluid.

[0039] Since the seals 10 have the same structure, only one of them will be described in detail in the following part; it is understood that the characteristics described with reference to the previously chosen seal 10 also apply in a completely equivalent manner to another seal 10 of the sealing group 1.

[0040] As can be seen more clearly in [Fig.3], the joint 10 comprises: a support part 11, configured to be coupled to the rotor element 4 in a manner fixed to the latter and therefore able to rotate around the axis A by means of the rotation that can be communicated by the rotor element 4; a sealing part 12, supported by the support part.

[0041] In more detail, the seal 10 comprises: an annular body 31 preferably made of rigid material (e.g., metal or rigid plastic) defining the support part 11; and sealing elements in an appropriate manner made of elastomeric material (for example EPDM rubber), carried by the annular body 31 and defining the sealing part 12.

[0042] The sealing portion 12 advantageously comprises: a first sealing lip 12a suitable for determining fluid tightness in order to prevent the entry into compartment 2 of contaminants present in the external environment 50; a second sealing lip 12b suitable for determining fluid tightness to prevent leakage of pressurized fluid in compartment 2 to the external environment 10.

[0043] Appropriately, the first sealing lip 12a is arranged in a more axially external position than the second sealing lip 12b, relative to compartment 2, and it faces the external environment 50.

[0044] The second sealing lip 12b faces compartment 2.

[0045] Given the symmetrical arrangement of the seals 10 with respect to compartment 2, the second sealing lips 12b are arranged, in use, facing each other across compartment 2.

[0046] Preferably, the joint 10 is of the type described in Italian patent application 102017000129950 filed in the name of the same applicant. In particular, the structure, formation, and parts composing each joint 10 should preferably be considered as corresponding to those of the joint described in that patent application.

[0047] The sealing group 1 advantageously comprises a support ring 13 having an annular formation around the axis A, configured to be assembled on the stator member 3 in a manner fixed to the latter and having an internal annular seating surface 13a and an external annular sliding surface 13b.

[0048] The sealing part 12 is placed in a fluid-tight manner against the external surface 13b and is suitable for sliding on the external surface 13b by means of the rotational movement communicated by the rotor element 4 to the support part 11.

[0049] Taking into consideration the above part, the first sealing lip 12a as well as the second sealing lip 12b are placed in sliding butt against the external surface 13b.

[0050] In other words, the first sealing lip 12a and the second lip 12b cooperate in a fluid-tight manner with the external surface 13b of the ring 13.

[0051] According to one aspect of the present invention, the sealing group 1 further comprises an annular retaining element 14 fixing the seals 10 to each other and to the support ring 13, thus defining a set of parts coupled together in a removable manner.

[0052] In other words, according to the invention, the seals 10, the support ring 13 and the retaining element 14 define parts assembled together in a removable manner of a compact sealing kit 100 which can be fitted between the stator element 3 and the rotor element 4 to hermetically seal the annular compartment 2 defined between them.

[0053] This particular and advantageous configuration therefore makes it possible to define a kind of sealing "cartridge" or in other words, a sealing group 1 in a single set of parts coupled together, which can be implemented in the relevant wheel body by means of a single shimming operation.

[0054] It is simply a matter of fitting the support ring 13 (which, as mentioned, already supports the seals 10 by coupling, using the retaining element 14) onto the member stator 3; during such a timing, the support parts 11 of the seals 10 are inserted with a predetermined interference into the annular radial space between the stator element 3 and the rotor element 4, rubbing on the internal surface 4a of the rotor element 4 until they reach compartment 2.

[0055] Once the predetermined axial position is reached, i.e. the seat of the sealing group 1, the support parts 11 are rigidly wedged internally on the rotor member 4, while the sealing parts are free to slide, in a fluid-tight manner, on the ring 13.

[0056] The assembly of the group therefore takes place in a single shimming movement, instead of requiring different assembly operations of the different parts separated from each other, as in the case of sealing groups for CTIS systems of the known type.

[0057] This entails significant savings in terms of time and cost, during assembly as well as during handling and / or replacement of the group or individual parts thereof.

[0058] Preferably, the support ring 13 is configured to be wedged, in correspondence with its internal surface 13a, on the stator member 3 directly and without interposition of parts.

[0059] Similarly, each support part 11 is configured to be coupled in a wedge-like manner to the internal annular surface 4a of the rotor element 4 directly and without interposition of parts.

[0060] Such provisions highlight the significant simplification of the architecture and the reduction of the components of group 1.

[0061] Advantageously, the support ring 13 comprises: a rigid part 15 carrying the external surface 13b and defining a sliding stop track for each sealing part 12; and an elastomer part 16 carrying said internal surface 13a and fitable in a fluid-tight manner onto the stator element 3.

[0062] Preferably, the rigid part 15 is made of metallic material.

[0063] In this way, optimal rigidity is guaranteed to the support ring 13 (guaranteed by the rigid part 15) ensuring at the same time adequate adhesion of the latter to the stator element 3 without the use of screws or other connecting elements between the two bodies, and also guaranteeing fluid tightness (by means of the elastomer part 16).

[0064] The retaining element 14 is arranged in correspondence with compartment 2 and is axially interposed between the seals 10.

[0065] In detail, the retaining element 14 has at least two, and in particular a multiple of two, retaining protrusions 17 extending over axially opposite parts of the retaining element 14 itself in the axial direction.

[0066] Each protrusion 17 hooks a respective seal 10 in order to maintain this seal axially engaged, with or without play, with the retaining element 14 itself.

[0067] In detail, the annular body 31 and the sealing elements of the seal 10, or rather the support part 11 and the sealing part 12, cooperate to define an annular chamber 18 communicating, in a fluidic manner, with the compartment 2 by means of at least one through hole 19 (the function of the annular chamber 18 is described in the Italian patent application 102017000129950 mentioned above); each protrusion 17 engages a respective through hole 19 to hook the annular body 11 of the relative seal 10.

[0068] Preferably, the support ring 13 comprises two annular semi-profiles 20 which are axially facing each other and held axially against each other by means of the action of the retaining element 14.

[0069] Each semi-profile 20 receives, by sliding radial abutment, on its own part of the external surface 13b, the sealing part 12 of a respective seal 10.

[0070] More specifically, each semi-profile 20 has an L-shaped cross-section and comprises a first part 21 oriented axially and a second part 22 oriented radially.

[0071] The second part 22 defines an axial shoulder for the other semi-profile 20.

[0072] Each semi-profile 20 is pushed axially towards the axial shoulder 22 of the other semi-profile 20 by means of the hooking of the aforementioned protrusion 17 with the respective through hole 19 and by means of the axial thrust exerted by the sealing part 12 which slides on the semi-profile 20 itself.

[0073] In this way, the parts of the ring-seal assembly are axially and radially sealed together, by means of the retaining element 14.

[0074] Preferably, as illustrated in particular in [Fig.3], the axial shoulder 22 is defined by the elastomer part 16 of the ring 13.

[0075] In other words, the shoulder between the two semi-profiles 20 takes place through their respective elastomeric parts 16.

[0076] In this way, a certain axial compressibility of the assembly is guaranteed, which contributes during the positioning / insertion operation of group 1 in the relative wheel body.

[0077] Ideally, the retaining element 14 comprises a series of axial fins 23 distributed angularly around the axis A and projecting from the axially opposite parts of the retaining element 14 itself ([Fig.4]).

[0078] In detail, some fins 23 face one seal 10, while the other fins 23 face the other seal 10, respectively.

[0079] Advantageously, the support part 11 of each joint 10 is placed in axial abutment against the respective fins 23.

[0080] In this way, correct positioning of the seals 10 relative to the ring 13 is guaranteed.

[0081] Preferably, the retaining element 14 is made from rigid plastic material.

[0082] In this way, the entire assembly exhibits greater rigidity. The retaining element 14, not compressing during the mounting of the group 1 in relation to the relative wheel body, i.e., between the relative stator element 3 and the rotor element 4, does not alter the final position of the parts regardless of the load required for assembly. This promotes a better and more secure arrangement of the various parts of the group.

[0083] According to an examination of the characteristics of the sealing group 1 carried out according to the present invention, the advantages which the latter makes it possible to obtain are highlighted.

[0084] In particular, the special and advantageous compact and "cartridge" configuration of the sealing group 1, in other words, makes it possible to define a sealing kit in a single set of coupled parts, which can be implemented in the relevant wheel body by means of a single shimming operation.

[0085] It is in fact sufficient to wedge the entire sealing group 1 (which, as mentioned, already includes the support ring 13, the seals 10 and the retaining element 14 coupled together) onto the stator member 3 or better between the stator member 3 and the rotor member 4; during this wedge-fitting, the support parts 11 of the seals 10 are inserted with predetermined interference into the annular radial space between the stator member 3 and the rotor member 4, rubbing against the internal surface 4a of the rotor member 4 until they reach the compartment 2.

[0086] In other words, once the pre-established axial position is reached, i.e. the seat of the sealing group 1, the support parts 11 will be rigidly wedged internally on the rotor element 4, while the sealing parts will be free to slide, in a fluid-tight manner, on the ring 13.

[0087] The assembly of group 1 therefore takes place in a single shimming movement, instead of providing different assembly operations of different parts separated from each other as in the case of sealing groups for known type CTIS systems.

[0088] This entails considerable savings in terms of time and cost, both during assembly and during handling and / or replacement of the unit or individual parts thereof.

[0089] In addition, the risk of assembly errors is considerably reduced, in that the operator has to perform a single insertion, in one go, of the whole group 1, in which the different elements are already well positioned relative to each other in their respective nominal positions.

[0090] It is clear that modifications and variants can be made to the sealing group 1 described and illustrated here, without going out of the protection framework defined by the claims.

[0091] In particular, a single sealing group 1 could be implemented for a pair of wheel bodies "twinned" on the same axle, i.e. having a hub (rotor element 4) in common.

[0092] In this case, it is sufficient to provide a split of the conduit downstream of the sealing group 1 (i.e. of the moving part 8 of the aforementioned circuit), for example by means of known valve means.

Claims

Demands

1. Sealing group (1) for sealing an annular compartment (2) formed between a stator element (3) and a rotor element (4) movable, relative to the stator element (3), in rotational motion about an axis (A), the sealing group (1) being configured to allow the leak-proof passage of a pressurized fluid between the stator element (3) and the rotor element (4) through the annular compartment (2) and to prevent the passage of contaminants from an external environment (50) into the annular compartment (2); the sealing group (1) comprising: an annular support ring (13) configured to be shimmed on the stator element (3) in a manner integral to the latter, and having an internal annular shimming surface (13a) and an external annular sliding surface (13b);a pair of annular sealing elements (10) arranged on axially opposite parts of the annular compartment (2) in order to hermetically seal the annular compartment (2) in a fluid-tight manner; each sealing element (10) comprising a support portion (11), configured to be coupled to the rotor element (4) in a manner fixed to the latter, and a sealing portion (12) carried by the support portion (11), placed in a fluid-tight manner against the external surface (13b) of the support ring (13) and adapted to slide on said external surface (13b) by means of the rotary motion imparted by the rotor element (4) to the support portion (11); wherein the sealing group (1) further comprises an annular retaining element (14) fixing the sealing elements (10) to each other and to the support ring (13), thus defining a set of parts removably coupled to each other.

2. Sealing group according to claim 1, in which the support ring (13) is configured to be wedged on the stator member (3), in correspondence with its internal surface (13a), directly and without interposition of parts.

3. Sealing group according to claim 1 or 2, wherein each support portion (11) is configured to be coupled, by shimming, on an internal annular surface (4a) of the rotor element (4) directly and without interposition of parts.

4. Sealing group according to any one of the preceding claims, wherein the support ring (13) comprises: a rigid part (15) carrying said external surface (13b) and defining a sliding stop track for each sealing part (12); an elastomeric part (16) carrying said internal surface (13a) and capable of being inserted in a fluid-tight manner onto the stator member (3).

5. Sealing group according to any one of the preceding claims, wherein the retaining element (14) is arranged in correspondence with the annular compartment (2) and is axially interposed between the sealing members (10); the retaining element (14) having at least two retaining protrusions (17) extending over axially opposite parts of the retaining element (14) itself in the axial direction and each hooking a respective sealing member (10) in order to keep this sealing member (10) axially engaged, with or without play, with the retaining element (14).

6. Sealing group according to claim 5, wherein each sealing member (10) has: an annular support body (31) defining said support part (11); and at least one sealing element (12a, 12b) defining said sealing part (12); the annular body (31) and the sealing element (12a, 12b) cooperating to define an annular chamber (18) communicating fluidically with the annular compartment (2) by means of at least one through hole (19); wherein each retaining protrusion (17) engages said respective through hole (19) to hook the annular body (31) of the relative sealing member (10).

7. A sealing group according to any one of the preceding claims, wherein the support ring (13) comprises two annular semi-profiles (20) axially facing each other and sealed against each other axially by means of the action of the retaining element (14), each semi-profile (20) receiving against each other radially by sliding, on its own part of said external surface (13b), the sealing part (12) of a respective sealing element (10).

8. Sealing group according to claim 5 or 6 and according to claim 7, wherein each semi-profile (20) has an L-shaped cross-section and comprises a first part (21) oriented axially and a second part (22) oriented radially, the second part (22) defining an axial shoulder for the other semi-profile (20), each semi-profile (20) being pushed axially towards the axial shoulder of the other semi-profile (20) by means of the hooking of said retaining protrusion (17) with the respective through hole (19) and by means of the axial thrust exerted by the sealing part (12) which slides on the semi-profile (20) itself.

9. Sealing group according to any one of the preceding claims, wherein the retaining element (14) is arranged in correspondence with the annular compartment (2) and is axially interposed between the sealing members (10); and wherein the retaining element (14) comprises a series of axial fins (23) distributed angularly about said axis (A) and projecting from the axially opposite parts of the retaining element (14) itself, in order to face one sealing member (10) or the other sealing member (10), respectively; the support part (11) of each sealing member (10) being placed in axial abutment against the respective fins (23).

10. Sealing group according to any one of the preceding claims, wherein the sealing members (10), the support ring (13) and the retaining element (14) define parts removably assembled together of a sealing kit (100) which can be inserted, by means of a single shimming operation, between the stator member (3) and the rotor member (4) to seal the annular compartment (2) defined between them.