ITTO20010419A1 - MANIFOLD, FOR EXAMPLE INTAKE MANIFOLD FOR MOTORCYCLE ENGINES. - Google Patents

Abstract

The manifold (1) comprises a flange (2) and a tube-like elastic part (4) made of elastomeric material, which are connected to one another without using adhesives. The function of mechanical connection of the two components (2, 4) is separate from the function of gas and liquid tightness. The flange (2) and the tube-like elastic part (4) are provided with complementary formations (5, 6) defining a first step-like part (7a, 7b) which ensures stable connection between the two components (2, 4) in conditions of mutual clamping. The same complementary formations then define together a second step-like part (8a, 8b) which confers the necessary preloading on a seal lip (10) of the tube-like part (4) of the manifold. A further step (11) ensures connection of the two components (2, 4) during storage and handing of the manifold. <IMAGE>

Description

DESCRIPTION of the industrial invention entitled: "Manifold, for example intake manifold for motorcycle engines"

TEXT OF THE DESCRIPTION

The present invention relates to the intake manifolds according to the preamble of claim 1.

Intake manifolds of this type are currently used as intake manifolds in internal combustion engines for motorcycles, both with two-stroke and four-stroke cycles. These intake manifolds are also likely to be used, for example, in engines for ultralight aircraft, snowmobiles and water scooters, engines for chainsaws, industrial and agricultural engines of various kinds, motors for hobbyists: these are generally engines equipped with single or equipped thermal units, in the case of multi-cylinder engines, of a series of single intake manifolds.

The flange of the manifold, that is the rigid part of the manifold, is generally provided with a series of holes which are used to mount the manifold on the engine by fixing to it a first end of the elastic duct part of the manifold. The fixing of the intake manifold on the engine is generally made by means of screws.

The other end of the flexible duct part is attached to the carburetor or throttle body. This generally occurs with a male / female fitting tightened externally with clamps: in some cases, however, a second flange with holes is used to fix the carburetor or the throttle body to the elastic part of the intake manifold. .

The gas and liquid tightness and the mechanical resistance to the applied loads are ensured by an adhesive deposited on the flange or flanges which serves to make the flange or flanges with the vulcanized elastomer which normally constitutes the elastic part of the duct completely integral and watertight. of the collector.

To ensure good adhesion with the elastomer, the surfaces of the flange must therefore be conveniently prepared (typically with a sandblasting and degreasing treatment) before the adhesive is deposited. The types of adhesive used vary according to the materials that make up the flanges and the type of elastomer. In some cases there are two different types of adhesive deposited on the flanges in successive times and after drying each deposited layer in the oven.

The elastomers most commonly used for the production of the elastic duct part are those based on compounds such as NBR, FPM, ECO, NBR PCV and their mixtures and in general types of elastomers capable of resisting aging phenomena in the presence of fuels and lubricants and variable loads applied: the weight of the carburetor or throttle body and the mechanical vibrations transmitted by the engine or vehicle movement. All this taking into account the fact that the elastic part of the manifold duct made of elastomer must preferably have viscoelastic characteristics such as to be able to dampen the mechanical vibrations transmitted from the engine to the carburetor / throttle body, also providing good thermal insulation between the engine and carburetor / body. throttle.

In addition to this, the fact of using an elastomer to make the elastic duct part of the manifold is also advantageous as regards the manufacturing process: in this way it is in fact possible to produce the undercut areas present in the part of the collector with relative ease. elastomer of the manifold.

As for the flange, the traditional choice is to use a metal support made of steel, aluminum alloy, zamak alloy or brass alloy.

An intimate and durable adhesive connection between the flange and the elastic part of the duct of the manifold made of elastomer has until now been considered an imperative requirement to be able to establish and maintain the necessary characteristics of gas and liquid tightness and mechanical resistance over time. (also with regard to vibratory and / or thermal stresses): this also in consideration of the fact that the metal material used to make the flange and the elastomer used to make the elastic duct part of the manifold are intrinsically dissimilar between them in different respects.

However, this choice is not optimal for the purposes of the manifold manufacturing process. Given the numerous intermediate and preparation phases (sandblasting, degreasing, deposition of the adhesive in one or more layers and their drying in the oven, loading of the flanges into the elastomer vulcanization mold) that are necessary, the procedure ends in fact by become rather complex and consequently onerous. This factor negatively affects the manufacturing cost of the manifold.

The present invention therefore aims to provide an intake manifold whose characteristics allow to overcome these drawbacks.

According to the present invention, this object is achieved thanks to an intake manifold having the characteristics referred to specifically in the following claims.

Basically, the solution according to the invention provides for the manifold to be made as a set of two components produced separately (flange and elastic duct part) and then mechanically joined together in the absence of any adhesive connection.

The term "in the absence of adhesive connection", as used in the present description and, if applicable, in the following claims, generally refers to the fact that the manifold according to the invention does not provide for the presence of adhesives intended to ensure in the time the sealing connection between the flange and the elastic duct part.

This term therefore refers to the absence of an intimate and continuous adhesive connection created during the manifold construction phase and destined to persist over time. The existence of such an intimate and continuous connection can easily be found in the solutions according to the known art by trying to separate the flange and the duct part which are adhesively connected to each other: the adhesive connection is so strong that the elastomeric material of the elastic duct part is it breaks before being able to separate even only marginally the flange from the elastic duct part.

Consequently, those solutions which should provide (for the most diverse reasons) the application of layers of material capable of creating - even indirectly - an adhesive connection between the flange and the elastic duct part of the manifold without however this translating into an effective intimate and continuous adhesive connection between the aforementioned parts in such a way as to ensure gas and liquid tightness and mechanical resistance to the loads applied to the manifold throughout its life profit of the same.

Basically, the solution according to the invention is based on the recognition of the fact that it is possible to perform the same sealing mechanical connection action traditionally performed by the adhesive by intervening on the coupling conditions between the two parts of the manifold. This in particular by separating and delegating to different parts of the coupling structure:

on the one hand, the function of mechanical connection between the two components (flange and elastic duct part), e

- on the other hand, the function of sealing against gases and liquids.

In the currently preferred embodiment of the invention, the sealing connection between the flange and the duct part of the manifold is made with profiled parts of complementary shape in which it is generally distinguishable:

- a first coupling region - usually hook-shaped - intended to ensure the stable mechanical connection between the two components, in particular after mounting on a motor, and a second coupling region - usually consisting of a shoulder - intended to give the necessary preload to the sealing lips of the elastic part of the manifold which seal gas and liquids.

Preferably, in order to further improve the stability of the mechanical connection, a preloading of the elastic part is provided, obtained by increasing its thickness.

Still preferably, a further formation has been introduced to ensure the connection of the two components during storage and handling of the assembled manifold.

The flange and the duct-shaped elastic part of the manifold can therefore be obtained with separate production processes and equipment. This way of proceeding, which provides for the mechanical assembly of the elastic part in a conduit on the flange, allows a reduction in cost and an improvement in the quality of the product. In particular, it is possible to easily carry out a non-destructive quality control of the piece while in case of use of adhesives the checks can only be of a destructive type.

The reduction in the manufacturing cost is linked to faster molding processes performed on lower cost machinery and to the fact that it is not necessary to prepare the surfaces for the deposition of the adhesives and to use adhesives. In addition, it is not necessary to store the flanges prepared with the adhesive in a very thorough cleaning condition in view of the connection through adhesion with the elastic duct part.

In any case, the solution according to the invention also lends itself to being made by overmoulding the elastic part in a conduit over the previously molded flange using another process.

The solution according to the invention also lends itself to being made by co-molding the elastic duct part with the flange made of plastic material, i.e. the two components are molded in a single particular production equipment by means of two successive injections of the two materials constituting the flange and the elastic part with duct. All this by avoiding the use of an adhesive connection and instead resorting to a purely mechanical connection achieved by decoupling the gas and liquid sealing function from the connection function aimed at ensuring mechanical resistance to the applied loads.

For manufacturing the flange, a die-cast metal material or (in a particularly advantageous embodiment with regard to manufacturing costs) a sheared and / or drawn metal material can be used. Alternatively, a plastic material such as a thermoplastic or thermosetting material loaded with reinforcing material can be used for the flange: it can be, for example, polyamide (e.g. PA66) or phenolic resin loaded with reinforcement material such as fiber glass (e.g. 30%).

The duct-like elastic part of the manifold according to the invention can be made with an elastomer of the type mentioned above or, in general, with any elastomeric material of the type used up to now to make the manifolds in question, or again - according to a particularly cost-effective alternative - using a thermoplastic elastomer. The present invention is very advantageous in relation to the use of thermoplastic elastomeric materials since this type of materials present large and serious problems of adhesion to flanges made of metallic or plastic materials. In fact, up to now it has not been possible and it is not known the use of thermoplastic materials to make the elastic duct part of the manifold essentially because there are no adhesives capable of ensuring the necessary adhesion between the rigid flange and the elastic duct part. . The cost advantages in using thermoplastic materials derive above all from very fast process times compared to the thermosetting elastomers (typically rubber) used before the present invention.

The invention will now be described, purely by way of non-limiting example, with reference to the attached drawings, in which:

Figure 1 is a first view of a manifold according to the invention,

Figure 2 is another view of a manifold according to the invention, observed from a point of view which is approximately diametrically opposite to the point of view of Figure 1,

Figure 3 is a section view along the line III-III of Figure 2

- figure 4 reproduces - in magnified scale - the part of figure 3 indicated by arrow IV, and - figure 5 is a section along the line V-V of figure 1.

In the figures of the annexed drawings, the numerical reference 1 generally indicates a manifold as an intake manifold of the type currently used on engines for two-wheeled vehicles or - in general - on engines of the type listed (moreover by way of example) in the introductory part of this description.

The characteristics and methods of use of manifolds of this type are to be considered as generally known in the art, and therefore such as not to require a detailed description here, also because in themselves they are not relevant for the understanding and implementation of the invention.

In this regard, it will be appreciated that the solution according to the invention is capable of being advantageously applied also to manifolds having dimensional, shape and structural characteristics quite different from those of the manifold 1 illustrated here by way of non-limiting example.

Basically, in the context of a manifold such as manifold 1 two essential parts are essentially distinguishable.

The first part consists of a support in the form of a flange 2 having an overall annular development. In the flange 2 are usually provided with the openings 3: in the example illustrated here there are two openings 3 located in diametrically opposite positions with respect to the annular development of the flange 2. The openings 3 allow to fix the flange 2 - and the manifold 1 in its complex - to the body of an engine M (marginally illustrated only in Figure 4) to which the manifold 1 is associated. This is done by means of screws (not shown) which pass through the openings 3.

This occurs according to known criteria, in particular as regards the fact that the flange 2 is positioned in such a way as to surround a corresponding intake opening provided in the body of the motor M.

The second part of the manifold 1 is constituted by an elastic duct part 4 (the duct conformation is better appreciated in Figure 5) intended to establish a flow path for the gas.This is typically the air-fuel mixture - towards the intake opening obtained on the motor around which the flange is mounted 2.

The duct-like elastic part 4 generally has a proximal end 4b (the one connected to the flange 2) and a distal end 4a (see Figure 2) for connecting a carburetor or throttle body (not shown).

The connection of the distal end 4a of the elastic duct part 4 with this carburetor or throttle body takes place by means of a male / female type fitting tightened with clamps (not shown).

As already mentioned, it is also possible to associate to the end 4a another flange provided with openings for fixing the carburetor or the throttle body on the manifold 1 by means of screws.

The same solution according to the invention adopted to connect the proximal end 4b of the elastic duct part 4 to the flange 2 can therefore also be used for the connection between the distal part 4a of the elastic duct part 4 and any additional flange used for fixing the carburetor or throttle body.

In the solution according to the invention, the connection between the proximal end 4b of the elastic duct part 4 and the flange 2 (and, optionally, the connection between the distal end 4a of the elastic duct part 4 and the second flange used for fixing the carburetor (not indicated in the drawings) is made exclusively by means of a mechanical connection, avoiding the adhesive connection until now considered almost imperative to ensure the necessary characteristics of gas and liquid tightness and mechanical resistance to the applied loads.

As regards the meaning to be attributed to the fact that, in the solution according to the invention, the connection between the parts 2 and 4 is made in the absence of an adhesive connection, reference is made to the terminological premise made previously.

In the embodiment of the invention illustrated in the attached drawings, the aforementioned mechanical connection between the flange 2 and the duct part 4 is obtained by providing along the edge of the orifice of the flange 2 a formation 5 having an approximately beak-like profile (with the characteristics better illustrated in the following) intended to cooperate in shape coupling relationship with a corresponding groove formation 6 provided along the contour of the proximal end of the elastic duct part 4.

The illustrated embodiment example (corresponding to a currently preferred embodiment of the invention) provides that the nose formation 5 protrudes towards the inside of the orifice of the flange 2 starting from the contour of the orifice itself. All this to engage the corresponding cavity or groove 6 provided along the contour of the proximal end of the duct-like elastic part 4, at the outer surface of the same. The possibility of mechanically coupling the flange 2 with the elastic part 4 is ensured by the elasticity of the elastic part 4.

Technicians skilled in the sector will appreciate the fact that, without prejudice to the interaction modalities of the complementary trainings 5 and 6, the respective positions could be modified without altering the final result achieved.

In particular (and without this example having to be considered exhaustive of the possible embodiment variants) it is possible to realize the nose formation 5 on the elastic duct part 4 and the groove 6 on the flange 2, or provide that, instead of protruding from the flange 2 towards the inside of the orifice of the same, the beak formation 5 is provided on a collar appendage that surrounds the edge of the aforesaid orifice, with the beak formation protruding towards the outside of said collar so as to be able to receive invested on of it the proximal end of the duct part 4 provided with the throat formation 6 on its internal surface. In any case it is the flange 2 which presses with a suitable preload value (the surface of the elastic duct part is slightly protruding with respect to the homologous surface of the flange 2) the surface 7b of the elastic duct part against the fixing surface of the manifold on the motor ensuring its stable locking.

By focusing attention on Figure 4, it will be noted that the nose formation 5 and the throat formation 6 jointly define - with a surface 7a provided on the formation 5 and a surface 7b provided in the formation 6 - a first coupling region having a general hook conformation.

In other words, the part of the nose formation 5 which extends from and distal to the surface 7a forms a sort of hook which is introduced into the throat formation 6 so as to embrace, by hooking it, the surface 7b.

Symmetrically, the apex portion of the proximal end 4b of the duct-like elastic part 4 starting from the surface 7b can be seen as a sort of other hook that embraces, hooking it, the surface 7a.

The overall arrangement is therefore such that any stress imparted to the manifold 1 in the direction of a possible relative distancing (therefore of a separation) of the flange 2 and of the duct-shaped elastic part 4 translates - precisely due to the coupling effect described - into a tightening and re-sealing of the coupling condition between the formation 5 and the formation 6.

It will be appreciated that the surfaces la and 7b can be easily brought into a position of mutual engagement (therefore in conditions of mutual coupling) by exploiting the characteristics of elastic compliance of the duct-like elastic part 4, made of elastomeric material.

This is particularly true when, according to a first possible embodiment of the manifold 1 according to the invention, the flange 2 and the elastic duct part 4 are made as distinct components obtained with two distinct manufacturing processes.

The same considerations relating to the condition of engagement in engagement between the complementary formations 5 and 6, however, are valid in an identical way also when, according to other possible embodiments of the invention, the manifold 1 is obtained by over-molding the elastic manifold part 4 above the flange 2, or again when the manifold 1 is made by co-molding the elastic duct part 4 together with a flange 2 made of a thermoplastic material (for example polyamide PA66 loaded with 30% of glass fibers).

The first step or step element defined jointly with the surfaces 7a, 7b therefore has the function of realizing the stable mechanical connection between the flange 2 and the elastic duct part 4 as regards primarily the mechanical resistance to the applied loads: this also applies as regards the possible vibratory loads and / or related to thermal dissipation phenomena.

In addition to the surfaces 7a, 7b (preferably located in correspondence with the distal part of the beak formation 5), the beak formation 5 and the throat formation 6 then have two further surfaces facing each other and cooperating with each other so as to define a second region coupling, also have a general step or step conformation.

These are the surfaces indicated with 8a and 8b, located in correspondence with the proximal portion (therefore the root region) of the beak formation 5. This means, in a complementary way, that the surface 8b is located in correspondence with the apex portion of the extremity proximal part of the elastic duct part 4. This apex portion is simply constituted by a sort of lip 10 which protrudes radially starting from the proximal end 4b of the elastic duct part 4.

When the manifold 1 is mounted on the motor body (schematically indicated by M in figure 4, where the manifold 1 is shown slightly spaced from the motor body M for clarity) and the flange 2 is tightened against this body by means of the screws passing through the openings 3, the lip part 10 is compressed (effectively squashed) between the outer surface of the motor body M and the surface 8a - in fact an annular shoulder - of the nose formation 5.

In these conditions, the lip 10 ensures the necessary gas and liquid seal of the connection of the manifold 1 with respect to the body of the motor M without using any adhesive.

In the solution according to the invention, this result is therefore obtained completely independently of the mechanical connection established between the flange 2 and the elastic duct part 4: the aforementioned mechanical connection is in fact achieved, mainly, in correspondence with the step defined by the surfaces 7a, 7b.

The gas-tight and liquid-tight connection with respect to the intake opening to which the manifold 1 is associated - is instead achieved precisely by the lip part 10 of the duct-like elastic part 4 of the manifold 1.

All this, therefore, without the flange 2 having a direct function in this sense, if not - of course - the function of pressing (through the shoulder surface 8a) the lip part 10 against the surface of the motor body M.

In figure 4, the numerical reference 10a indicates a surface groove (usually defined by one or more grooves and / or ridges) obtained on the face of the lip part 10 intended to be turned towards the engine body M in order to further improve the sealing action against gases and liquids.

Again for the same reason, in the currently preferred embodiment of the invention, the lip part 10 and the portions of the proximal end 4b of the elastic duct part 4 adjacent to it are sized in such a way that, with the collector 1 assembled, the surface at which the grooves 10a are preferably provided is slightly protruding with respect to the homologous surface of the flange 2. In this way it is possible to give the lip 10 a sort of elastic preload, improving its sealing characteristics when the manifold it is fixed on the body of the motor M by compressing the aforementioned protruding part.

The numerical reference 11 finally indicates an annular relief provided along the contour of the elastic part with conduit 4 in correspondence with the side of the groove formation 6 opposite the surface 7b defining the first coupling step between the flange 2 and the elastic part with conduit 4.

The annular relief 11, which protrudes from the external surface of the duct part 4, is intended to cooperate with the external part of the nose formation 5 in order to prevent the disengagement of the same nose formation 5 with respect to the throat formation 6.

The relief 11 can therefore be seen as a sort of third step which has been provided in order to further reinforce the connection of the flange 2 and of the elastic part of the conduit 4, avoiding any unwanted separation during storage and handling of the manifold 1 assembled before mounting on the M.

Naturally, the principle of the invention remaining the same, the details of construction and the embodiments may be varied widely with respect to what has been described, without thereby departing from the scope of the present invention.

Claims (24)

CLAIMS 1. Manifold comprising an elastic duct part (4) of bearing elastomeric material associated with at least one end (4b) a flange (2) of rigid material, characterized in that said elastic duct part (4) and said flange (2 ) are connected together in conditions of gas tightness and resistance to applied loads in the absence of adhesive connection. 2. Manifold according to claim 1, characterized in that said elastic duct part (4) and said flange (2) are distinct components, coupled together by exploiting the elastic characteristics of said elastomeric material. 3. Manifold according to claim 1, characterized in that said elastic duct part (4) is constituted by elastomeric material overmoulded on said flange (2). 4. Manifold according to claim 1, characterized in that said elastic duct part is co-molded with said flange (2). 5. Manifold according to claim 4, characterized in that said flange (2) is made of plastic material. 6. Manifold according to claim 5, characterized in that said plastic material is a thermoplastic material, such as a polyamide, preferably PA66 7. Manifold according to claim 5, characterized in that said plastic material is a thermosetting material such as a phenolic resin. 8. Manifold according to claim 5 or claim 6, characterized in that said plastic material is loaded with reinforcing material. 9. Manifold according to claim 8, characterized in that said reinforcing material is in the form of fibers, such as glass fibers. 10. Manifold according to claim 1, characterized in that said flange (2) is of metallic material. 11. Manifold according to claim 10, characterized in that said metallic material is selected from the group comprising: steel, aluminum alloy, zamak alloy or brass alloy. 12. Manifold according to claim 10 or claim 11, characterized in that said flange (2) is of sheared and / or drawn metal material. 13. Manifold according to any one of the preceding claims, characterized in that said flange (2) and said elastic duct part (4) have complementary formations (5, 6) connected to each other in a mating relationship, said complementary formations having at least a first coupling region (7a, 7b), intended to provide a mechanical connection between said flange (2) and said elastic duct part (4), and at least a second coupling region (8a, 8b) intended to provide the seal to the gases and liquids of the collector. 14. Manifold according to claim 13, characterized in that said first coupling region (7a, 7b) is defined by respective surfaces of said complementary formations (5, 6) coupled together according to a general hook formation susceptible after mounting on the motor to exert a crushing action on said elastic part (4) to further improve the mechanical stiffness of the coupling. 15. Manifold according to claim 13 or claim 14, characterized in that said second coupling region (8a, 8b) comprises a surface (8a) capable of exerting a squeezing action on said elastic duct part (4) under conditions sealing. 16. Manifold according to claim 15, characterized in that said elastic duct part (4) has an apex portion essentially shaped like a lip (10) protruding from the elastic duct part (4) itself; said lip portion (10) being capable of being forced into a crushing ratio by at least one surface (7a) of said second coupling region. 17. Manifold according to claim 16, characterized in that said lip portion (10) is provided, on its external surface with respect to the elastic duct part (4), with a sealing surface groove (10a). 18. Manifold according to claim 16 or claim 17, characterized in that said lip portion (10) and / or the region of said elastic duct part (4) adjacent to it are at least marginally protruding with respect to said flange part (2). 19. Manifold according to any one of claims 13 to 18, characterized in that both (5) and the other (6) of said complementary formations essentially consist of a protruding nose formation (5) and a throat (6) which receives, at least in part, said protruding beak formation (5). 20. Manifold according to claim 19, characterized in that said first coupling region (7a, 7b) and said second coupling region (8a, 8b) are respectively provided, in the distal part and in the proximal part, of said beak formation. 21. Manifold according to claim 19 or claim 20, characterized in that said nose formation (5) and said throat formation (6) are provided, respectively, on said flange (2) and on said elastic duct part ( 4). 22. Manifold according to claim 21, characterized in that said flange (2) has an annular conformation with an orifice and in that said nose formation (5) projects towards the inside of the orifice of said flange part (2 ). 23. Manifold according to claim 21 or claim 22, characterized in that said throat formation (6) is provided on the external surface of said elastic duct part (4) it is at least marginally protruding with respect to said flange part (2) . 24. Manifold according to any one of claims 1 to 23, characterized in that said duct-like elastic part (4) has an annular projection (11) as an antagonistic function of the separation movement of said flange (2) with respect to said elastic part a duct (4). All substantially as described and illustrated and for the specified purposes.