Patent Description:
In particular, the blow-by gas filtration assembly of the present invention is fluidly connectable to the crankcase ventilation circuit of an internal combustion engine system inside of a vehicle to receive blow-by gases (from said crankcase) and filter from them the suspended particles contained therein.

Specifically, "blow-by gas" means oil vapours vented from the crankcase of an internal combustion engine during its operation. In particular, said blow-by gases have a composition similar to that of exhaust gases and are generated by combustion of the air/fuel mixture in the combustion chamber. Instead of reaching the exhaust gas emission circuit, these gases leak into the lower portion of the crankcase, passing alongside the cylinders and bringing carbon particles and oil drops with them. In the present discussion, for the sake of simplicity, blow-by gases are considered to consist of air and suspended particles; said suspended particles comprise oil droplets and/or carbonaceous particulates.

In the state of the art, solutions of filtration assemblies that is fluidly connectable to the crankcase and suitable for venting it from blow-by gases are known of.

Specifically, blow-by gas filtration assembly solutions which separate unwanted suspended particles from the aforesaid blow-by gases are known of, comprising a filter group having such purpose.

In the state of the art, a plurality of embodiments of filtration assemblies comprising a filter group comprising a porous-type filter medium, driven in rotation by a specific electric drive such that the suspended particles are separated from the air both by passing through the porous material and by the action of the centrifugal force are known of.

In some known embodiments, the filtration assembly comprises a special electric drive engaged to said filter group to command it in rotation.

These embodiments, typically present complex and imprecise engagement means between the electric drive and the filter group. This typically entails complex assembly methods, but above all difficulty in obtaining a filtration assembly in which the electric drive and filter group are correctly aligned with respect to the axis of rotation. A solution of filtration assembly with the above mentioned drawbacks is disclosed in document <CIT>.

In the aforesaid state of the art the need is therefore strongly felt to have a blow-by gas filtration assembly that solves such problems.

The purpose of the present invention is to provide a new embodiment of a blow-by gas filtration assembly with simplified and certain reciprocal positioning of the filter group and the electric drive.

Such purpose is achieved by the blow-by gas filtration assembly claimed in claim <NUM>. The dependent claims show preferred embodiment variants having further advantageous aspects.

Further characteristics and advantages of the invention will, in any case, be evident from the description given below of its preferred embodiments, made by way of a non-limiting example with reference to the appended drawings, wherein:.

With reference to the appended drawings, reference numeral <NUM> denotes a blow-by gas filtration assembly suitable for performing a filtration/separation action on particles (liquid and/or solid) suspended in the gas stream.

Said blow-by gas filtration assembly <NUM> is fluidly connectable to a crankcase ventilation circuit of an internal combustion engine of a vehicle to receive blow-by gases and filter from them the suspended particles contained therein returning a stream of clean gas (i.e. filtered) to other vehicle systems such as, for example, to the engine air intake circuit communicating with the combustion chamber of the internal combustion engine.

Preferably, said blow-by gas filtration assembly <NUM> is directly mountable to the crankcase of an internal combustion engine of a vehicle. In particular, the present invention is not limited to this feature; in one embodiment the blow-by gas filtration assembly <NUM> is a stand-alone device comprising respective inlet and outlet ports communicating respectively with the crankcase, for receiving blow-by gases to be filtered, and with the air intake circuit, for recirculating the gas stream filtered of solid and liquid particles towards the combustion chamber.

According to the present invention, the filtration assembly <NUM> comprises an X-X axis with respect to which the components described below extend or are positioned.

According to a preferred embodiment, the blow-by gas filtration assembly <NUM> comprises an assembly body <NUM>. Preferably, the other components of the system are positioned in or on said assembly body <NUM>, as described extensively below and evident from the exemplary figures attached below.

In particular, the assembly body <NUM> comprises a filtration chamber <NUM> in which filtration/separation operations of the blow-by gases take place. The filtration chamber <NUM> is therefore fluidly connected to the crankcase ventilation circuit of an internal combustion engine of a vehicle to receive dirty blow-by gases, i.e. comprising suspended particles (solid and/or liquid), and emit clean blow-by gases, i.e. cleaned of suspended particles, into the engine air intake system.

According to a preferred embodiment, the assembly body <NUM> comprises respective blow-by gas inlets and outlets.

Preferably, the assembly body <NUM> comprises an inlet mouth <NUM> fluidically connected with the crankcase ventilation circuit of a vehicle to receive the blow-by gases to be filtered. Preferably, said inlet mouth is made radially, spaced apart from the X-X axis, for example substantially parallel thereto. Preferably, said inlet mouth is made on the side wall of the assembly body <NUM>. Preferably, said inlet mouth is made on the wall of the assembly body <NUM> defining the filtration chamber <NUM>.

In addition, preferably, the assembly body <NUM> comprises an outlet mouth <NUM>. Said outlet mouth <NUM> is radially spaced apart from the X-X axis, for example substantially parallel thereto.

According to a preferred embodiment, said outlet mouth <NUM> is made on the coupling flange of the assembly body <NUM> to the internal combustion engine crankcase. Preferably, the outlet mouth <NUM> and the inlet mouth <NUM> are mutually spaced along the X-X axis. Preferably, the outlet mouth <NUM> and the inlet mouth <NUM> are mutually axially parallel.

Furthermore, according to a preferred embodiment, the assembly body <NUM> comprises a main body <NUM> and an auxiliary body <NUM> mutually engageable as amply described below and as shown by way of example in the attached figures.

According to the present invention, the blow-by gas filtration assembly <NUM> comprises a filter group <NUM>, specifically suitable for performing said filtration/separation operations of the particles suspended in the blow-by gases. Said filter group <NUM> is positionable and operates in the filtration chamber <NUM>.

The filter group <NUM> extends along the X-X axis comprising a central cavity <NUM>.

According to a preferred embodiment, the filter group <NUM> has a substantially cylindrical shape.

The filter group <NUM> is crossable radially by blow-by gases.

According to the present invention, the filter group <NUM> is crossable by the blow-by gases in the radial direction. Preferably, the filter group <NUM> is crossable by blow-by gases radially from the outside towards the inside.

Preferably, the inlet mouth <NUM> is radially facing the filter group <NUM>. According to a preferred embodiment, the inlet mouth is radially facing the outer surface of the filter group <NUM>.

Preferably, the outlet mouth <NUM> is, in turn, substantially radially facing the filter group <NUM>.

In other words, the filter group <NUM> identifies, in the filtration chamber <NUM>, a dirty side in which there are blow-by gases to filter and a clean side in which there are filtered blow-by gases. The inlet mouth <NUM> is fluidically connected with said dirty side, the outlet mouth <NUM> is fluidically connected with said clean side.

According to a preferred embodiment, the filter group <NUM> comprises a filter medium <NUM>. The filter medium <NUM>, which is crossable radially comprises a non-woven fabric pleated in the form of a star or a porous cylindrical septum.

Moreover, according to a preferred embodiment, the filter group <NUM> comprises a first filter plate <NUM> and a second filter plate <NUM> mutually arranged at the axial ends of the filter medium <NUM>.

According to a preferred embodiment, the filter group <NUM> comprises a central structure <NUM> which is housed inside the filter medium <NUM> and joins the two filter plates <NUM>, <NUM>, so that the filter plates <NUM>, <NUM> are integrally connected in rotation. Preferably, said central structure <NUM> has a plurality of radial through openings <NUM> suitable to allow the passage of the fluid being filtered.

According to a preferred embodiment, the central structure <NUM> is a stand-alone component that is mountable on the first filter plate <NUM> and the second filter plate <NUM>.

According to other embodiment variants, the central structure <NUM> is made in one piece with the first filter plate <NUM> or the second filter plate <NUM>.

In addition, according to a preferred embodiment, the filter group <NUM> comprises an outer structure <NUM> which surrounds the filter medium <NUM> on the outside and joins the two filter plates <NUM>, <NUM>. Preferably, said outer structure <NUM> has, in turn, a plurality of radial through openings <NUM> suitable to allow the passage of the blow-by gases.

According to a preferred embodiment, the cavity <NUM> extends through at least one plate, preferably through the first filter plate <NUM>. In a preferred embodiment, the second filter plate <NUM> is closed. In one embodiment variant, the second filter plate <NUM> in turn has an opening.

According to the present invention, moreover, the filtration assembly <NUM> comprises a command drive operatively connected to the filter group <NUM> to command it in rotation about the X-X axis.

According to the present invention, moreover, the filtration assembly <NUM> comprises an electric drive <NUM> operatively connected to the filter group <NUM> to command it in rotation about the X-X axis.

According to a preferred embodiment, the electric drive <NUM> comprises an electric motor unit <NUM> comprising a stator <NUM> and a rotor <NUM>. The actuation of the stator <NUM> results in the rotation of the rotor <NUM>. In particular, the circulation of electric current in the windings of the stator <NUM> determines a rotating magnetic field capable of determining the rotation of the rotor <NUM>, and therefore of the components connected to it such as the filter group <NUM>. According to a preferred embodiment, the electric motor group <NUM> is of the brushless type.

According to a preferred embodiment, the electric motor makes it possible to vary the rotation speed of the filter group <NUM> according to the operating conditions of the vehicle.

According to a preferred embodiment, the electric drive <NUM> is electrically connected to a vehicle command unit, ECU, to command the operation of the filtration assembly <NUM> according to the operating needs of the vehicle. Preferably, the electric drive <NUM> is electrically connected to the ECU vehicle command unit by means of an electrical connector <NUM>, preferably integrated in the auxiliary body <NUM> of the assembly body <NUM>.

According to a preferred embodiment, the electric drive <NUM> comprises an electronic card to communicate with the vehicle command unit to command the operation of the filtration assembly according to the operating conditions of the vehicle.

According to a preferred embodiment, the rotor <NUM> comprises one or more elements in ferromagnetic material arranged in the shape of a toroid.

According to the present invention, the blow-by gas filtration assembly <NUM> comprises a support and command shaft <NUM>.

Such shaft <NUM> extends along the X-X axis and is specially suitable to be operatively connected to the filter group <NUM> and the electric drive <NUM>.

According to a preferred embodiment, as described below and as shown in the appended drawings, the shaft <NUM> extends inside the filter group <NUM> and inside the electric drive <NUM>.

According to a preferred embodiment, the shaft <NUM> comprises within it at least one air duct <NUM> through which the blow-by gases flow.

According to a preferred embodiment, said air duct <NUM> extends axially through the entire shaft <NUM>. In other words, the shaft <NUM> is a hollow body.

According to an embodiment variant, said air duct <NUM> extends axially through only a portion of the shaft <NUM>.

According to a preferred embodiment, the shaft <NUM> is made as a single component.

According to a preferred embodiment, the shaft <NUM> is made as a single component in a thermoplastic material.

According to an alternative embodiment, the shaft is a hollow body composed of two or more parts mechanically couplable to each other (e.g. by welding, mechanical couplings, screws or the like) reversibly or irreversibly so as to form a single component the constituent parts of which rotate synchronously upon command by the electric drive <NUM>.

According to the present invention, the shaft <NUM> comprises distinct portions with different purposes and, above all, suitable to engage or to be engaged by distinct components.

According to the present invention, the shaft comprises a filter portion <NUM> on which the filter group <NUM> is mounted. Preferably, in said filter portion <NUM> the blow-by gases flow, being fluidically connected to the cavity <NUM>; in said filter portion <NUM> the air duct <NUM> extends.

According to the present invention, moreover, the shaft <NUM> comprises a command portion <NUM> operatively connected to the electric drive <NUM>. In other words, the shaft <NUM> comprises a command portion <NUM> suitable to interact with the electric drive <NUM> to determine the rotation of the shaft <NUM> and the filter group <NUM> connected to it. In particular, the rotor <NUM> is mounted on said command portion <NUM>.

In particular, according to the present invention, the rotor <NUM> and the filter group <NUM> are mounted integrally to the shaft <NUM> respectively to the command portion <NUM> and to the filter portion <NUM> in such a way that a commanded rotation of the rotor <NUM> corresponds to a rotation of the shaft <NUM> and thus of the filter group <NUM>. In particular, in the present description, "integrally" means that the rotor <NUM> and the filter group <NUM> are mechanically connected to the shaft <NUM> to rotate in unison (or synchronously).

According to a preferred embodiment, the rotor <NUM> is integrated on the shaft <NUM>, the latter preferably made of thermoplastic material, by overmoulding.

According to a preferred embodiment, the rotor <NUM> is integrated on the shaft <NUM> by shape coupling or by interference.

According to the present invention, the blow-by gas filtration assembly <NUM> comprises a support bearing <NUM> suitable to support the shaft <NUM> to the assembly body <NUM> in such a way as to keep it centred to the X-X axis and allow its rotation with respect to the assembly body <NUM>.

In particular, the shaft <NUM> comprises a bearing portion <NUM> on which said support bearing <NUM> is mounted.

The support bearing <NUM> is radially engaged to the support portion <NUM> and externally to the assembly body <NUM>.

In particular, the support bearing <NUM> comprises an inner bearing ring <NUM> and an outer bearing ring <NUM>.

Preferably, said inner bearing ring <NUM> is engaged to the shaft <NUM> and said outer bearing ring <NUM> is engaged to the assembly body <NUM>.

According to the present invention, said support portion <NUM> is axially positioned between the filter portion <NUM> and the command portion <NUM>.

In particular, according to the present invention, the filter group <NUM> comprises a filter thread <NUM> and the filter portion <NUM> of the shaft <NUM> comprises a shaft thread <NUM> mutually engageable upon screwing.

According to the present invention, in the screwing engagement between the filter group <NUM> and filter portion <NUM> and the resulting reciprocal displacement in the axial direction, the filter group <NUM> engages the support bearing <NUM>. Preferably, the filter group <NUM> axially engages the support bearing <NUM>.

Preferably, the axial engagement of the filter group <NUM> with the support bearing <NUM> prevents further screwing of the filter group <NUM> on the shaft <NUM>.

Preferably, the axial engagement of the filter group <NUM> with the support bearing <NUM> prevents further movements of the support bearing <NUM>.

Preferably, the axial engagement of the filter group <NUM> with the support bearing <NUM> keeps the position of the support bearing <NUM> fixed in relation to the assembly body <NUM>.

Preferably, upon screwing, the filter group <NUM> discharges a closing torque onto the support bearing <NUM>. In other words, the support bearing <NUM> acts as an axial shoulder to the filter group <NUM>. In other words, the support bearing <NUM> acts as an end stop to the rotation when the filter group <NUM> is screwed onto the shaft <NUM>.

Preferably, the axial engagement of the filter group <NUM> with the support bearing <NUM> allows the necessary closing torque to be achieved to ensure the synchronous rotation of the filter group <NUM> with the shaft <NUM>.

According to the present invention, moreover, in the screwing engagement between the filter group <NUM> and filter portion <NUM> and the resulting reciprocal displacement in the axial direction, the filter group <NUM> engages and axially blocks the support bearing <NUM>.

Preferably, the filter group <NUM> comprises an annular shoulder <NUM> suitable to engage the inner bearing ring <NUM> of the support bearing <NUM>. In particular, said annular shoulder <NUM> is suitable to engage a surface extending radially inside the inner swivel ring <NUM>. That is to say that said annular shoulder <NUM> engages an inner bearing ring shoulder <NUM>.

Preferably, the filter group <NUM> comprises an annular shoulder <NUM> suitable to engage the inner bearing ring <NUM> of the support bearing <NUM>, preferably to axially contact the inner bearing ring <NUM> of the support bearing <NUM>.

According to a preferred embodiment, the annular shoulder <NUM> is a planar surface arranged at least in part on a plane transverse to the X-X axis, preferably orthogonal to the X-X axis, suitable to at least partially engage the support bearing <NUM>, preferably the inner bearing ring <NUM> of the support bearing <NUM>.

According to a further preferred embodiment, the annular shoulder <NUM> is an undulated or knurled or irregular surface arranged at least partially on a plane transverse to the X-X axis, preferably orthogonal to the axis X-X, suitable to at least partially engage the support bearing <NUM>, preferably the inner bearing ring <NUM> of the support bearing <NUM>.

According to a further preferred embodiment, the annular shoulder <NUM> is an abutment surface arranged at least in part on a plane transverse to the X-X axis, preferably orthogonal to the X-X axis, formed by a series of reciprocally spaced ribs, preferably equidistant, positioned on the filter group for example on the first plate or the central structure.

According to a preferred embodiment, the annular shoulder <NUM> is comprised in the first filter plate <NUM>. Preferably, the annular shoulder <NUM> surrounds the first plate opening <NUM>.

According to a preferred embodiment, the annular shoulder <NUM> is comprised in the central structure <NUM>. Preferably, the annular shoulder <NUM> surrounds the first plate opening <NUM>.

Preferably, the annular shoulder <NUM> extends in height parallel to the X-X axis.

Preferably, the annular shoulder <NUM> has a thickness that extends radially with respect to the X-X axis.

According to a preferred embodiment, the screwing between filter thread <NUM> and shaft thread <NUM> involves the axial translation of the filter <NUM> and the engagement of the annular shoulder <NUM> with the bearing <NUM> by performing a tightening action on it.

According to a preferred embodiment, the filter thread <NUM> is the lead screw and the shaft thread <NUM> is the screw.

According to a preferred embodiment, the filter thread <NUM> is the screw and the shaft thread <NUM> is the lead screw.

According to a preferred embodiment, the filter group <NUM> is screwed to the shaft <NUM> in a rotary direction opposite the rotary direction in which the shaft <NUM> and therefore the filter group <NUM> is driven in rotation by the electric drive <NUM> during filtration operations.

According to a preferred embodiment, the support bearing <NUM> is positioned on the shaft <NUM> in a defined axial position, being on one side engaged by the filter group <NUM> and on the other side engaged by the rotor <NUM> or at least one shaft abutment element <NUM> or by the assembly body <NUM>.

In other words, the support bearing <NUM> is sandwiched between the filter group <NUM> and an axially fixed abutment present on the shaft <NUM>. That is to say, the support bearing <NUM> is clamped onto the shaft <NUM>.

According to a preferred embodiment said fixed abutment is made integrally with the shaft <NUM>. Preferably, the shaft <NUM> comprises at least one shaft abutment element <NUM> suitable to perform the function of fixed abutment for the support bearing <NUM>.

According to a preferred embodiment said fixed abutment is realised by the rotor <NUM> integrally mounted to the shaft <NUM>.

According to yet a further preferred embodiment, said fixed abutment is realised by the assembly body <NUM>.

According to a preferred embodiment, said fixed abutment is suitable to axially engage the inner bearing ring <NUM> of the support bearing <NUM>.

According to a preferred embodiment the shaft <NUM> further comprises an outflow portion <NUM> fluidically connected to the air duct <NUM> and comprising at least one outflow window <NUM> through which the blow-by gases flow.

According to a preferred embodiment, therefore, the air duct <NUM> extends at least between the filter portion <NUM> and the outflow portion <NUM>. According to a preferred embodiment, in which the filter is crossed in a radial direction from the outside to the inside, the filtered blow-by gases flow through the filter portion <NUM> towards the outflow portion <NUM>. According to a preferred embodiment, the outflow portion <NUM> is axially positioned between the filter portion <NUM> and the command portion <NUM>.

Preferably, the outflow portion <NUM> is axially positioned between the support portion <NUM> and the command portion <NUM>. In other words, the support portion <NUM> is positioned axially between the filter portion <NUM> and the outflow portion <NUM>.

According to a preferred embodiment, wherein the outflow portion <NUM> comprises a plurality of outflow windows <NUM> arranged annularly around the X-X axis, wherein each window <NUM> is separated from the consecutive window by a shaft abutment element <NUM>.

According to a preferred embodiment, the outflow portion <NUM> acts as an axial abutment for the support bearing <NUM>.

According to a preferred embodiment, the second filter plate <NUM> is closed and the shaft <NUM> crosses the first plate <NUM> along the X-X axis through a respective first plate opening <NUM>. Preferably, the filter portion <NUM> comprises at least one air intake <NUM> through which the blow-by gases flow.

In other words, said air intake <NUM> fluidically connects the air duct <NUM> and the cavity <NUM>.

Preferably, the filter portion <NUM> comprises at an axial end thereof an air intake <NUM> through which the blow-by gases flow. Preferably, said air intake <NUM> is positioned orthogonally to the X-X axis. Preferably, said air intake <NUM> is positioned parallel to the X-X axis. Preferably, said air intake <NUM> has a plurality of openings, orthogonally to the X-X axis and/or parallel to the X-X axis.

According to a preferred embodiment, instead, the second filter plate <NUM> has a second plate opening <NUM>.

Preferably, the shaft <NUM> crosses said second plate opening <NUM> along the X-X axis.

According to a preferred embodiment, the shaft <NUM> engages the edges of said second plate opening <NUM>. Preferably, said engagement between the shaft <NUM> and the second filter plate <NUM> is carried out by threading.

According to a preferred embodiment, the filter portion <NUM> comprises radial openings <NUM> suitable to place in fluidic communication the air duct <NUM> and the cavity <NUM>.

According to a preferred embodiment, the shaft <NUM> sealingly engages the filter group <NUM> in two sealing regions.

Preferably, the radial openings <NUM> are positioned axially between the two sealing regions.

Preferably said two regions are positioned at the two filter plates <NUM>, <NUM>. Preferably, said engagement is achieved by two specific threaded couplings.

According to a preferred embodiment, said filter thread <NUM> is comprised in the first filter plate <NUM>.

According to a preferred embodiment, said filter thread <NUM> is comprised in the second filter plate <NUM>.

According to a preferred embodiment, said filter thread <NUM> is comprised in the central structure <NUM>.

According to a preferred embodiment, the shaft <NUM>, preferably in the filter portion <NUM>, comprises an anti-rotation element <NUM> suitable to perform an action in the radial direction to engage the filter group <NUM> screwed to the shaft <NUM>. In other words, the anti-rotation element <NUM> is suitable to prevent unscrewing between the filter group <NUM> and the shaft <NUM>. In other words, the anti-rotation element <NUM> is suitable to prevent unwanted unscrewing of the threaded coupling.

According to a preferred embodiment, the anti-rotation element <NUM> is an elastically yielding element in a radial direction, during the screwing operations.

Preferably, the anti-rotation element <NUM> is suitable to snap-fit into a radial through opening <NUM> made on the central structure <NUM>.

According to a preferred embodiment, the anti-rotation element <NUM> has inclined sliding surfaces specially shaped to facilitate the action in the radial direction.

Preferably, the anti-rotation element <NUM> has a first inclined sliding surface suitable to interact during the screwing operations. Furthermore, preferably, the anti-rotation element <NUM> has a second inclined sliding surface suitable to interact to allow unscrewing operations (which require a minimum initial rotation force).

According to a preferred embodiment, the inclination of the first inclined sliding surface is different from the inclination of the second inclined sliding surface. In particular, the two sliding surfaces are respectively inclined diversely from each other so as to adequately dimension the rotary force that allows screwing, the force maintaining the threaded coupling and the force that allows disengagement.

According to a preferred embodiment, the shaft <NUM> comprises a closing wall (not shown), inside the air duct <NUM> suitable to close said air duct <NUM> to force the outflow of the filtered blow-by gases through the at least one outflow window <NUM>.

According to a preferred embodiment, the closing wall is positioned at the command portion <NUM>, proximal to the outflow portion <NUM>.

Preferably, said closing wall <NUM> is shaped to facilitate the outflow of blow-by gases towards the at least one outflow window <NUM>.

As mentioned above, the assembly body <NUM> comprises a main body <NUM> and an auxiliary body <NUM> mutually sealingly engageable along the X-X axis.

Preferably, the coupling between the main body <NUM> and an auxiliary body <NUM> hermetically delimits the filtration chamber <NUM>. Preferably, said filtration chamber <NUM> is housed in the main body <NUM> closed at one axial end by the auxiliary body <NUM>.

Preferably, both the inlet mouth <NUM> and the outlet mouth <NUM> are comprised in the main body <NUM>.

According to a preferred embodiment, the main body <NUM> and the auxiliary body <NUM> in the reciprocal coupling further delimit an outflow chamber <NUM> fluidically connected to the outflow portion <NUM> of the shaft <NUM> and preferably to the outlet mouth of the blow-by gases <NUM>. Preferably, the outflow chamber <NUM> is sealingly separated from the filtration chamber <NUM>, fluidically connected to the clean side of the filtration chamber by means of the shaft <NUM>. Preferably, said outflow chamber <NUM> is fluidically connected to the clean side of the filtration chamber by means of the at least one outflow window <NUM>.

According to a preferred embodiment, the outflow chamber <NUM> is at least partially housed in the main body <NUM>.

Preferably, the outflow chamber <NUM> extends at least partially around the X-X axis. Preferably, the outflow chamber <NUM> has an annular extension.

According to a preferred embodiment, the outflow chamber <NUM> is radially delimited by a collar wall <NUM> of the auxiliary body <NUM> placed in a region proximal to the X-X axis and by a housing wall <NUM> comprised in the main body <NUM> placed in a region distal from the X-X axis.

Moreover, according to a preferred embodiment, the outflow chamber <NUM> is axially delimited by a bottom wall <NUM> and by a top wall <NUM> extending radially relative to the X-X axis.

Moreover, according to a preferred embodiment, the outflow chamber <NUM> is axially delimited by a bottom wall <NUM> and by a top wall <NUM> comprised in the auxiliary body <NUM>, extending radially relative to the X-X axis starting from the collar wall <NUM>.

According to a preferred embodiment, the outflow chamber <NUM> is fluidically connected to the outflow portion <NUM> by means of at least one body window <NUM> through which the blow-by gases coming out of the at least one outflow window <NUM>, or in input towards the at least one outflow window <NUM>, flow.

Preferably, the collar portion <NUM> comprises at least one body window <NUM>.

According to a preferred embodiment, the collar portion <NUM> is annularly facing the shaft <NUM> at the at least one outflow window <NUM>.

Preferably, therefore, the at least one outflow window <NUM> and the at least one body window <NUM> are radially aligned.

According to a preferred embodiment, both the bottom wall <NUM> and the top wall <NUM> sealingly engage the main body <NUM>.

Preferably, as shown in the accompanying drawings, the top wall <NUM> engages the main body <NUM> in a radial direction. Preferably, proximal to the housing wall <NUM>, the main body <NUM> comprises an abutment step <NUM> axially engageable by the secondary body <NUM>.

Preferably, as shown in the accompanying drawings, the bottom wall <NUM> engages the main body <NUM> in a radial direction. Preferably, at one radial end thereof, the bottom wall <NUM> is suitable to house a gasket element.

According to a preferred embodiment, the outflow chamber <NUM> is shaped so as to facilitate the outflow of the blow-by gases.

According to a preferred embodiment, the outflow chamber <NUM> is shaped so as to facilitate the channelling towards the outlet mouth <NUM> of the filtered blow-by gases. Preferably, for example, the outflow chamber <NUM> is radially wider in a region distal from the X-X axis. Preferably, in fact, the bottom wall <NUM> extends in a specially inclined radial direction, i.e. conically shaped.

According to a preferred embodiment, the shaft extends partially into the main body <NUM> and partially into the auxiliary body <NUM>.

According to a preferred embodiment, the auxiliary body <NUM> comprises a stator housing <NUM>' in which the stator <NUM> is housed.

Preferably, the stator <NUM> is inserted in the stator housing <NUM>' in an axial direction.

Preferably, the stator <NUM> is integral with the auxiliary body <NUM>. For example, the auxiliary body <NUM> integrates the stator <NUM> internally. Preferably, the auxiliary body <NUM> is made of thermoplastic material and the stator <NUM> is co-moulded together with the auxiliary body <NUM>.

According to a preferred embodiment, the support bearing <NUM>, preferably the outer bearing ring <NUM>, axially engages the auxiliary body <NUM> on the opposite side to the filter group <NUM>.

Preferably, the support bearing <NUM> engages the collar wall <NUM>.

According to a preferred embodiment, the blow-by gas filtration assembly <NUM> comprises an upper auxiliary support bearing <NUM> engaged to the shaft <NUM> to support it to the assembly body <NUM>.

According to a preferred embodiment, the upper auxiliary support bearing <NUM> is positioned axially spaced from the support bearing <NUM>.

According to a preferred embodiment, the upper auxiliary support bearing <NUM> is positioned engaged to the shaft <NUM> near the electric drive <NUM>, for example engaging the auxiliary body <NUM>.

According to a preferred embodiment, the upper auxiliary support bearing <NUM> is engaged to the command portion <NUM>.

According to a preferred embodiment the upper auxiliary support bearing <NUM> is housed inside the command shaft <NUM>. Preferably, the upper auxiliary support bearing <NUM> radially engages on the inner side a centring pin <NUM>, provided on the auxiliary body <NUM>, and radially on the outer side, the inner surface of the command portion of the shaft <NUM>.

According to a preferred embodiment, the upper auxiliary support bearing <NUM> is housed inside the shaft <NUM> and closes the air duct <NUM>, facilitating the outflow of the blow-by gases.

According to a preferred embodiment, the upper auxiliary support bearing <NUM> is mounted outside the command shaft <NUM>.

According to a preferred embodiment, the blow-by gas filtration assembly <NUM> also comprises a second lower auxiliary support bearing <NUM>.

Preferably, the lower auxiliary support bearing <NUM> is suitable to ensure the centring of the shaft <NUM> on the X-X axis so that it is centred with the stator axis.

Preferably, the lower auxiliary support bearing <NUM> is placed proximal to the second filter plate <NUM>.

According to a preferred embodiment, the lower auxiliary support bearing <NUM> is engaged to the second filter plate <NUM>.

According to a further preferred embodiment, the lower auxiliary support bearing <NUM> is engaged to the shaft <NUM>, preferably at the filter portion <NUM>.

For example, the lower auxiliary support bearing <NUM> is engaged to the shaft <NUM>, at an end thereof which overruns through the second plate opening <NUM> and is engaged to the assembly body <NUM>, preferably at the main body <NUM>.

According to the present invention, the terms support bearing, upper auxiliary support bearing and lower auxiliary support bearing mean both sliding bearings and roller bearings.

According to a preferred embodiment, the engagement of the bearings with the shaft and with the respective support body is sealed.

According to a preferred embodiment, the shaft <NUM> is made of thermoplastic material obtained by means of a single moulding operation.

Preferably, the shaft <NUM> is made of polyphenylene sulphide (PPS).

Preferably, the shaft <NUM> is made of a polyphenylene sulphide (PPS) based material.

Preferably, the shaft <NUM> is made of a polyphenylene sulphide (PPS) based material reinforced with fibreglass (PPS + GF15, PPS + GF30, PPS + GF40).

Preferably, the shaft <NUM> is made of a nylon-based material (PA, PA <NUM>, PA <NUM> or a mixture thereof).

Preferably, the shaft <NUM> is made of nylon-based material reinforced with fibreglass. (PA+GF, PA <NUM>+ GF35, PA <NUM>+PA <NUM>+GF <NUM>).

Preferably, the shaft <NUM> is made of a material comprising a polyamide-based compound (e.g. PPA).

[<NUM>] According to a preferred embodiment, the shaft <NUM> is made of metal. Preferably, the shaft <NUM> is made of aluminium alloy.

Innovatively, the blow-by gas filtration assembly of the present invention widely fulfils the purpose of the present invention. Innovatively, the blow-by gas filtration assembly presents a new and innovative shape, but above all a new and innovative support and engagement method of the various components.

Advantageously, the filtration assembly of the blow-by gases has a simply structured shaft and is therefore simple to produce.

Advantageously, the filtration assembly uses an abutment surface provided by a component operatively coupled to the shaft (such as the bearing) to ensure a preset torque of the threaded coupling, thus simplifying the structure of the shaft and making the filtration assembly more compact.

Advantageously, the filtration assembly uses an abutment surface provided by the support bearing operatively coupled to the shaft, which, being a lubricated component, reduces the friction generated by rotation and therefore the stresses on the electric drive, making the assembly more reliable.

Advantageously, the support bearing is positioned in a certain position. In particular, advantageously, the support bearing is positioned on the shaft in a certain position. In particular, advantageously, the support bearing is positioned on the assembly body in a certain position.

Advantageously, the alignment between the rotation axis of the filter group and the rotation axis of the electric motor is guaranteed without the use of additional alignment/compensation elements.

Advantageously, the rotation axis of the filter group and the rotation axis of the electric motor are always aligned with each other. Advantageously, the blow-by gas filtration assembly has extremely compact dimensions.

Advantageously, the assembly body is designed to identify and fluidically separate the filtration chamber from the outflow chamber in a simple and effective manner. Advantageously, the assembly body comprises the main body and the auxiliary body, the mutual engagement of which defines said chambers.

Advantageously, the blow-by gas filtration assembly has an extremely limited number of components. Advantageously, the blow-by gas filtration assembly has fewer components for alignment and rotation than the prior solutions.

Advantageously, the blow-by gas filtration assembly has a limited number of gaskets. Advantageously, the filter group axially and sealingly engages the support bearing allowing the elimination of additional gaskets between the shaft and the filter group.

Advantageously, the threaded coupling simplifies the assembly of the filtration assembly.

Advantageously, the threaded coupling between the shaft and filter group allows the support bearing to be axially locked in the correct working position, eliminating the need for additional components for such purpose.

Advantageously, the region of reciprocal engagement between the filter group and the shaft is very compact, thus making it possible to optimise the use of available space by offering, for example, the possibility of increasing the filtering surface area of the filter group and therefore, with the same flow rate of gas to be filtered, reducing the pressure drops imposed by the filtration assembly on the crankcase ventilation circuit.

Advantageously, the threaded coupling simplifies and makes the assembly of the filtration assembly more reliable, allowing the filter group to be assembled to the shaft, which in turn is coupled to the electric drive and supported by the auxiliary body, then joining said auxiliary body to the main body in sequence, without the need to use additional components to ensure alignment between the rotation axis of the filter group and the rotation axis of the electric drive.

Advantageously, the filtration assembly of the present invention guarantees compliance with the dimensional tolerances related to the mechanical coupling between the auxiliary body (e.g. electric motor) and the main body of the assembly body and at the same time guarantees the alignment between the axis of rotation of the electric motor and the axis of rotation of the shaft, and therefore of the filter group.

Advantageously, the preset torque of the threaded coupling on the support bearing provided between the shaft and the filter group makes it possible to minimise clearance along the shaft axis, reducing stresses on the components that make the filter group rotate and thus prolonging the service life of the components included in the assembly.

Advantageously, the preset torque of the threaded coupling on the support bearing makes it possible to support and at the same time rotate the filter element, reducing the number of components required for this purpose and therefore the weight of the assembly, thus helping to increase its reliability.

Advantageously, the preset torque of the threaded coupling on the support bearing makes it possible to reduce the number of components and the weight of the filtration assembly, thus reducing the power of the electric drive, simplifying its structure and reducing its costs.

Advantageously, the reduction in weight of the assembly makes it possible to contribute to the construction of lighter vehicles and thus reduce fuel consumption.

Advantageously, the threaded coupling realised with the screwing direction opposite the main direction of rotation of the command shaft during filtration operations prevents the undesired disengagement of the filter group, thus realizing a safe and self-closing fixing system.

Advantageously, the threaded coupling simplifies service and maintenance of the filter element, also making it safer and cleaner.

Claim 1:
A blow-by gas filtration assembly (<NUM>), fluidically connectable to a crankcase ventilation circuit of an internal combustion engine in order to receive the blow-by gases and to filter them from the suspended particles contained therein, wherein the filtration assembly (<NUM>) has an axis (X-X) and comprises:
an assembly body (<NUM>) comprising a filtration chamber (<NUM>), an inlet mouth (<NUM>) for the blow-by gases to be filtered and an outlet mouth (<NUM>) for the filtered blow-by gases;
ii) a filter group (<NUM>) comprising a central cavity (<NUM>) through which the blow-by gases is radially crossable, preferably from the outside to the inside;
iii) an electric drive (<NUM>) that is operatively connected to the filter group (<NUM>) in order to command in rotation about the axis (X-X) and to carry out the filtration operations, wherein the electric drive (<NUM>) comprises an electric motor (<NUM>) that comprises a stator (<NUM>) and a rotor (<NUM>);
iv) a support and command shaft (<NUM>), which extends along the axis (X-X) and comprises:
- a filter portion (<NUM>) on which the filter group (<NUM>) is mounted;
- a command portion (<NUM>) on which the rotor (<NUM>) is mounted; and
- a support portion (<NUM>) that is axially positioned between the filter portion (<NUM>) and the command portion (<NUM>) ;
v) a support bearing (<NUM>) radially engaged to said support portion (<NUM>) on the inside and to the assembly body (<NUM>) on the outside;
wherein the blow-by gas filtration assembly (<NUM>) is characterized by the fact that the filter group (<NUM>) and the filter portion (<NUM>) comprise a filter thread (<NUM>) and a shaft thread (<NUM>), respectively, screwable to one another, wherein the filter group (<NUM>) screwed to the shaft (<NUM>) axially engages with the support bearing (<NUM>), wherein said axial engagement between the filter group (<NUM>) and support bearing (<NUM>) prevents additional screwing of the filter group (<NUM>).