Title of Invention

A SEALING ASSEMBLY FOR AN INTERNAL COMBUSTION ENGINE

Abstract

The present invention relates to an internal combustion engine, particularly a 4-stroke engine, comprising: -at least one engine housing (2) provided with at least a first through bore (2'): -at least one engine shaft (3) provided with a first free end (3'), the shaft (3) being associated to the housing (2), so that its free end (3') ex- tends through the first through bore (2'); and -at least one chamber (4) for positioning at lest one shaft driving means, the chamber being associated to the engine housing (2) and having at least one second through bore (4') cooperating with the first through bore (2') of the housing (2). The engine further comprises at least a sealing assembly (5) preferably associated to the second through bore (4'), provided with a body (50) associable to the chamber (4) or to the housing (2), to which a sealing element (51) is associated, which is compressible against the engine housing (2). The body (50) is substantially cylindrical in shape and the sealing ele- ment (51) is substantially in the form of a resilient ring. This sealing assembly (5) is also described in detail.

Full Text

Specification of the Patent of Invention for: "AN INTERNAL COMBUSTION ENGINE AND A SEALING ASSEMBLY The present invention relates to an internal combustion engine, particularly a four-stroke engine, provided with a sealing assembly for sealing against leakages of engine lubricating oil, as well as the sealing assembly properly said. Description of the Prior Art Conventionally, 4-stroke internal combustion engines like those that operate according to the Otto and Diesel cycles, have at least two shafts that rotate inside it, namely: the crankshaft or turning shaft, connected to the piston/rod assembly, and the camshaft or turnable shaft, associated to the crankshaft in a synchronic way at an angular velocity rate of 1:2. In engines of conventional architecture, which have formed the majority for many years, the camshaft was positioned on the block, laterally with respect to the crankshaft and, due to it proximity to the latter, the driving of the cam shaft was effected by means of a pair of gears or a small chain. This driving was carried out, as a rule, inside the block or at least the cha¬in/gears was (were) isolated from the outside, so that the camshaft did not present any end projecting out of the engine block. Therefore, the leakages . of lubricating oil in this region were not relevant. In this regard, the engines that operate according to the diesel cycle, conventionally, have the camshaft on the block, driven by the crank¬shaft by means of a chain, which also drives the fuel injection pump. This chain is located in an appropriate chamber, which receives the engine lubri¬cating oil, in order to enable its correct operation. However, one has concluded that the positioning of the camshaft at the engine head provided greater efficiency to the engine, due to the re¬duction in the quantity of movable pieces. The positioning of the camshaft at the engine head makes un¬feasible the use of gears for driving it, mainly due to its distance from the crankshaft. So, it becomes necessary to use chains or rubber cambelts for driving the camshaft. Each of these systems has advantages and disadvantages, the rubber cam- belt having, as its great advantage, low cost and silent operation. However, its useful life is greatly impaired when it comes into contact with petroleum- derived products, such as grease, lubricating oil and fuel (gasoline or diesel oil). The chain, in turn, has also silent operation and durability (and, consequently, reliability) much longer than that of the cambelt, although its cost is higher and the need for lubrication is imperious. Therefore, in the case of those engines where the camshaft is driven by a chain, constant lubrication is imperious, and it is preferably car¬ried out with the same lubricating oil of the engine; otherwise the useful life of the driving and moving chain will be considerably reduced. However, it is necessary that the engine should not present any leakage of oil in the lubrication region of the driving chain, which was achieved so far by using gasket of plastic or polymeric material, or else by using sealing glues. However, even though these elements function satisfac¬torily, they have to be replaced during the engine maintenance routine (as for instance during the disassembly of the timing case of the engine, where the driving chain is located), and during its reassembly the amount of failures that used to cause leakage of lubricating oil was not negligible, and this led to the need for redoing the service, otherwise the engine would remain with con¬stant leakages. Evidently, in addition to the dissatisfaction of the client, there was loss due to the need for redoing the service. Unfortunately, it had not been developed a 4-stroke internal com¬bustion engine, especially an engine that would operate according to the Diesel cycle, provided with means that prevent leakage of lubricating oil from the engine through the lubrication galleries of the timing case, where the driv¬ing chain of the camshaft is located, and that would bring about efficacy against leakage and be easy to assemble or disassemble, without difficulty in achieving the correct sealing again. Objectives of the Invention The main objective of the present invention is to provide a 4- stroke internal combustion engine, preferably but not compulsorily having a camshaft positioned at the engine head, provided with at least one sealing assembly that prevents leakages of lubricating oils through the lubrication galleries of the timing case and that enables one to assembly and disassem¬ble the engine during the maintenance services in an easy and safe manner, with guarantee of sealing against leakages. A second objective of the present invention is to provide a seal¬ing assembly that prevents leakages of lubricating oil from the lubrication gal¬leries of the timing case and that is ease to mount on the engine, so as to ensure sealing in an easy and safe way. Brief Description of the Invention The first objective of the present invention is achieved by means of an internal combustion engine, particularly a four-stroke engine, compris¬ing: - at least one engine housing provided with at least a first through bore, - at least one engine shaft provided with a first free end, the shaft being associated to the housing in such a way that its free end will extend through the first through bore, and - at least one chamber for positioning at least one shaft driving means, the chamber being associated to the engine housing and having at least one second through bore cooperating with the first through bore of the housing. The engine additionally comprises at least one sealing assembly, which provides sealing of the first and second through bores when the cham¬ber for positioning the shaft driving means is associated to the engine hous¬ing. The second objective of the present invention, in turn, is achie¬ved by means of a sealing assembly, particularly developed for use on an internal combustion engine provided with: - at least one engine housing provided with a first through bore, - at least one engine shaft provided with a first free end, - and at least one chamber for positioning at least one shaft driv¬ing means, the shaft being associated to the housing in such a way that its free end extends through the first through bore, and the chamber being as¬sociated to the engine housing and having at least one second through bore cooperating with the first through bore of the housing. The sealing assembly additionally comprises a body to which a compressible sealing element is associated when the chamber rests against the engine housing. The present invention has the following advantages, among oth¬ers: • Guarantee of lubricating the chain with the engine lubricating oil itself, preventing leakages through the first and second through bores; ► Ease maintaining the engine, without the need for adjusting the assembly to ensure the desired sealing, since the latter effects the sealing automatically, being enough for the timing case to be correctly fixed to the engine head and / or block. » Reduced manufacture cost and easy installation of the sealing assembly. Brief Description of the Drawings The present invention will now be described in greater detail on the basis of an embodiment represented in the drawings. The figures show: - Figure 1 is a perspective rear view of the block of the internal combustion engine of the present invention, associated to a chamber for po¬sitioning chain also known as timing case; - Figure 2 is a perspective view of the engine head of the present invention, associated to the timing case, including the camshaft and the driv¬ing chain; - Figure 3 is a perspective view in detail of the internal combus¬tion engine of the present invention, wherein one can see the engine head, the camshaft and the timing case; - Figure 4 is a perspective view in detail of the camshaft of the engine illustrated in figure 3, together with the sealing assembly of the pre¬sent invention; - Figure 5 is a perspective sectional view of the engine illustrated in figure 3, where one can see the engine head, the camshaft, the timing case and the sealing assembly of the present invention associated therebe¬tween; - Figure 6 is view in detail of figure 5 with the sealing assembly; - Figure 7 is a perspective sectional view of the engine of the present invention, wherein one can see the engine head, the camshaft, the timing case, the camshaft driving chain, and the sealing assembly of the pre¬sent invention associated therebetween, including the arrows that identify the flow of the lubricating oil; - Figure 8 is a view in detail of the engine head of the engine of the present invention, including the camshaft and its driving toothed wheel, without the timing case; and - Figure 9 is a perspective top view of the engine head of the present invention associated to the timing case, wherein one can see the sealing assembly and the arrows that indicate the flow of the lubricating oil. Detailed Description of the Figures According to a preferred embodiment and as can bee seen from figure 1, the present invention relates to an internal combustion engine 1, particularly a 4-stroke engine that operates according to the Diesel cycle, although it may evidently relate to an engine that operates according to the Otto cycle or even to any type of engine whatever. The preferred embodi¬ment in the form of a 4-stroke Diesel engine is, therefore, not a limitant. Whatever the engine 1 may be, it compulsorily comprises an en¬gine head 2, generically speaking, that corresponds to the engine structure and aggregates all its internal elements, either fixed or movable, such as pis¬tons, rods, crankshafts, valves, etc. Additionally, the engine 1 comprises at least one shaft 3 that ro¬tates inside the housing 2, so as to enable its operation. This shaft may be the crankshaft, the camshaft, an intermediate shaft for moving peripheral components or any other necessary or desirable shaft of the engine. What¬ever this shaft may be, it has a free end 3' for association of a pulley or a to¬othed wheel that transmits or receives angular movements as for example, a toothed pulley In order to enable the correct positioning of the shaft 3, mainly concerning to its free end 3', the housing 2 has at least one through bore 2'. In the great majority of the internal combustion engines that op¬erate according to the DieseJ and Otto cycles, the engine housing 2 com¬prises an engine block 20, provided with cavities for positioning the pistons (also called cylinders), galleries for flow of lubricating oil and, in most cases, galleries for flow of cooling fluids. The engine block is represented in figure 1 of this specification. Associated to the block 20, the internal combustion engines comprise at least one engine head 21, which is the part of the housing 2 illus¬trated in figures 2, 3, 5, 6, 7, 8, 9, which, as a rule, contains the engine valves, rocker arms, etc. (not shown). Therefore, the expression "engine housing" designates geneti¬cally engine block and/or head. In the preferred embodiment, the engine 1 comprises an engine head 21, provided with a through bore 2' for positioning the free end 3' of the camshaft 3, so that its free end will extend through the first through bore 2'. Evidently, the through bore 2' may assume any necessary or de¬sirable shape, as for example a cylindrical hole, a semicircular notch, etc. In order to enable the operation of the engine 1, there have to be means for driving the camshaft 3, which should move synchronically with the crankshaft (not shown), turning at half the angular speed of the latter. For this purpose, these driving means have to prevent any kind of slipping between crankshaft and camshaft 3, or another shaft, as the case may be. In the preferred embodiment, it is used a metallic distribution chain (shown in figures 2 and 7 with reference number 41), an element that enables silent operation of the engine, besides having a long useful life, if correctly lubricated. Due to these characteristics, and also to their high reli¬ability and long durability (which are interconnected concepts), the use of distribution chains in new projects of engines, with camshaft at the engine head is being preferred. However, one may evidently use rubber cambelts, gears or any other driving elements. In order to enable the correct lubrication of the distribution chain 41, to guarantee its durability and silent operation, one preferably uses the same engine lubricating oil, which is diverted by lubrication galleries for this purpose. In this way, is eliminated the need for a specific and exclusive lubri¬cant for the distribution chain, thus reducing manufacture and maintenance costs of the engine. A more detailed explanation of this point is given later herein. In order to enable the operation of the engine 1, the crankshaft comprises a driving toothed pulley, which makes it possible to move the chain and, the camshaft 3 concomitantly, which also has a moving toothed pulley 30 at its free end 3', which can be seen in figures 2, 7 and 8. In order to protect the chain 41 against external agents and to ensure that the lubricating oil from the engine used for lubricating it will not be lost, the engine 1 comprises a chamber 4 for positioning the chain, hereinaf¬ter called timing case, which is preferably associated to the engine head 21 and to the engine block 20. However, there may be engines where the timing case is fixed only to the engine block 20 or only to the engine head 21. The timing case 4 has a structure provided with means for fixing it to the engine block 20 and/or engine head 21, which comprises a second through bore 4' for allowing the passage of the free end 3' of the camshaft 3, and additionally has at least one third through bore 4" for passage of the free end of the crankshaft, the one where the respective toothed pulley is located. For the correct positioning of the chain, the structure defines a cavity 40. The timing case 4 further has a protective cover (not shown). In the preferred embodiment of the presently disclosed engine, the second through bore 4' is substantially circular in shape, but evidently it may be of any other necessary or desirable shape, as for example, a cylin¬drical hole, a semicircular notch or any other functional shape. In the engine 1 of the preferred embodiment of the invention, the timing case 4 is fixed to the engine block 20 by screwing, but evidently it may be used any other fixing means, and, even, it may also be fixed to the engine head 21. Alternatively, however, one may provide an engine 1 according to the present invention in which the through bore 2' is located at the engine block 20, like those engines provided with a camshaft 3 positioned at the en¬gine block. Further, one could provide an engine 1 in which the existing through opening would be developed to enable the correct positioning of other shaft than the camshaft 3, as for example, the crankshaft, which is al¬ways located at the engine block 20. The timing cases 4 of the engines con¬figured in this way have particularities of geometric construction that make them functional, but they continue to be conceptually identical to the box 4 herein revealed. As mentioned before, the lubricating oil from the engine is used for correct lubrication of the distribution chain 41, in order to guarantee its durability and silent operation. The lubricating oil reaches the chain 41 initially passing through the first through bore 2' of the engine head 2 and then the second through bore 4' of the timing case 4. Evidently, it is not provided any kind of lubricant retainer at the free end 3" of the camshaft 3 to enable the mentioned oil flow. This flow can be viewed in figures 7 and 9, where the white arrows represent the lubricating oil. After lubricating the distribution chain 41 and the respective toothed pulleys, the lubricating oil returns to the oil pan (oil reservoir not shown) through the third through bore 4" or any other opening. However, it is imperious that there should be no leakage of en¬gine oil while the latter passes through the first and second through bores 2', 4'. In the engines of the prior art, this was achieved by means of a gaskets made of polymeric material or by means of sealing glues, solutions that, al¬though functional while the engine was new, ended up being little effective as the engine was used and above all during the maintenance, when there was the non-negligible and even common possibility of a mechanic not positioning the gasket correctly, or else not applying the glue in a sufficient amount or in an adequate position. As a result, the engines presented leakages of oil in this region, obliging the mechanic to redo the service. In order to prevent any trace of leakage of lubricating oil during its passage through the first and second through bores 2', 4', there is a seal¬ing assembly 5. Preferably, the assembly 5 is fixed to the timing case 4 and is located inside the second through bore 4', projecting towards the engine head 21. The sealing assembly 5 then provides sealing between the first and the second through bores 2', 4' when the timing case 4 for positioning the shaft driving means is associated to the engine block 20 and to the en¬gine head 21. The assembly 5 further guarantees this sealing even if the tim¬ing case 4 and the engine head 21 are unaligned. The assembly 5 comprises a body 50, by preference substan¬tially cylindrical in shape, provided with a through hole (in which the free end 3' of the camshaft 3 is located), to which a sealing element 51 is associated, which by preference is substantially in the form of a resilient o-ring type ring. When the timing case 4 and the engine head 21 are unaligned, the sealing is guaranteed thanks to the o-ring and to the respective manufacture toler¬ances. The body 50 is rigidly associated to the timing case 4, in the re¬gion of the second through bore 4', preferably by means of three fixing screws arranged at 120° with respect to each other. However, it is evident that the fixation may be effected by any other means, also in other regions of the box 4 than that adjacent the second bore 4'. Additionally, it is clear that the body 50 may be fixed to the engine head 21 in the region of the first through bore 2'. In order for the sealing assembly 5 to be functional, it should permit the passage of lubricating oil from the engine head 21 towards the timing case 4 (through the first and the second through bores 2', 4') and, for this purpose, the diameter of the through bore of the body 50 has to be at least fractionally larger than the diameter of the free end 3' of the camshaft 3, thus forming an annular passage 52 that enable the flow of the lubricating oil. When the timing case 4 is fixed to the engine (preferably on the engine block 20), the resilient ring 51 is pressed against the head 21 and de¬forms in such a way that it prevents leakage of lubricating oil that might pass through the space between the first and the second through bores 2', 4'. View of details of the mounting of the sealing assembly 5 can be seen in fig¬ures 6 and 7. It is important to remind that the body 50 is preferably manufac¬tured from steel 1010, for resistance to compression without deforming and ensuring that only compression of the sealing ring 51 will occur, which always provides correct sealing. Since the sealing assembly 5 is fixed only to the timing case 4 and since the sealing of the first and second through bores 2', 4' is achieved by compressing/deforming the resilient ring 51, it becomes easy to disas¬semble and assemble the box 4 when the engine needs repair, without any need to adjust the assembly 5 for making correct sealing again. During the remounting of the timing case 4 on the engine block 20 and on the engine head 21, two situations may occur. In a first situation, if the sealing assembly 5 is in good shape, that is to say, if the sealing ring 51 does not have any considerable permanent deformations, and is in condition to guarantee a correctly sealing, the timing case may be mounted again with the same assembly 5. As the box is firmly screwed to the block 20 and to the head 21, the sealing ring 51 is gradually compressed so as to ensure sealing. In a second situation, if the sealing assembly 5 is in bad condi¬tion (with the sealing ring having permanent deformations, which prevents total sealing, for instance), it is replaced and the timing case 4 may then be mounted to the engine block 20. Further, it is possible to provide a sealing assembly 5 wherein the sealing ring 51 may be replaced independently of the replacement of the body 50. As mentioned before, there is the possibility of the sealing as¬sembly being fixed to the head 21, and then the sealing ring 51 is com¬pressed against the timing case, as it is screwed to the engine block and en¬gine head 20, 21, with identical results regarding the sealing and ease of re¬assembly. Evidently, the shape of the body 50 may vary, mainly due to the variation in the shape of the second through bore 4', as well as the sealing element 51 may assume other shape than that of an O-ring. It should be further noted that since the sealing assembly 5 is novel and inventive, it is an invention, itself, and is defined in the accompany¬ing claims. The sealing assembly 5 may have particularities in both the body 50 and the sealing element 51, as a function of the specific architecture of an engine for which it has been developed, without, however, these variations failing to be embraced by the protection of the scope of the claims. Moreover, one may provide an engine 1 having more than one sealing assembly, as for example, an engine provided with a first sealing as¬sembly 5 intended to seal the openings designed for the camshaft 3 (or cam¬shafts if the engine has more than one), a second sealing assembly 5 for sealing the openings designed for the crankshaft and also engines provided sealing assemblies 5 to seal openings designed for other different shafts, such as intermediate driving shaft of peripheral components, among others. The engine 1 of the present invention has the following highlights as advantages in comparison with the engines of the prior art: • guarantee of lubrication of the chain with the lubricating oil from the engine, preventing leakages through the first and second through bores 2', 4'; • ease of maintenance of the engine, without the need to adjust the assembly 5 in order to ensure the desired seal¬ing, since the latter makes the sealing automatically; for this purpose suffice it for the timing case 4 to be correctly fixed to the engine block 20; • reduced manufacture costs and easy installation of the sealing assembly 5; • guarantee of sealing, even if the timing case 4 and the head 21 are unaligned. A preferred embodiment having been described, it should be un¬derstood that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents. CLAIMS 1. An internal combustion engine, particularly a 4-stroke engine, comprising: - at least one engine housing (2) provided with at least a first through bore (2'); - at least one engine shaft (3) provided with a first free end (3'), the shaft (3) being associated to the housing (2), so that its free end (3') ex¬tends through the first through bore (2'); and - at least one chamber (4) for positioning at least one shaft driv¬ing means, the chamber being associated to the engine housing (2) and hav¬ing at least one second through bore (4') cooperating with the first through bore (2') of the housing (2), the engine (1) being characterized in that it com¬prises at least one sealing assembly (5) that seals the first and second through bores (2", 4') when the chamber (4) for positioning the shaft driving means is associated to the engine housing (2). 2. An engine according to claim 1, characterized in that the seal¬ing assembly (5) comprises a substantially cylindrical body (50), to which a sealing element (51) substantially in the shape of a resilient ring is associ¬ated. 3. An engine according to claim 1 or 2, characterized in that the sealing assembly is associated to the second through bore (4'). 4. An engine according to claim 3, characterized in that the body (50) is rigidly associated to the chamber (4) and the resilient sealing ring (51) is compressed against the engine housing (2). 5. An engine according to claim 4, characterized in that the body (50) is made from 1010 steel. 6. An engine according to claim 1, characterized in that the en¬gine housing (2) comprises an engine block (20) and at least one engine head (21), the first bore (2') being located in the engine head (21). 7. An engine according to claim 1, characterized in that the en¬gine shaft (3) is a camshaft. 8. An engine according to claim 7, characterized in that the free end (3') of the camshaft (3) has a driving pulley or toothed wheel (30). 9. An engine according to claim 8, characterized in that the chamber (4) for positioning the shaft driving means corresponds to a struc¬ture that defines a cavity (40) for positioning a shaft driving means in the form of a distribution chain (41). 10. A sealing assembly, for use on an internal combustion engine provided with: - at least one engine housing (2) provided with at least one first through bore (2'); - at least one engine shaft provided with a first free end (3'); and - at least one chamber (4) for positioning at least one shaft driv¬ing means; - the shaft (3) being associated to the housing (2) so that its free end (3') extends through the first through bore (2') and the chamber (4') be¬ing associated to the engine housing (2) and having at least one second through bore (4') cooperating with the first through bore (2') of the housing (2); - the sealing assembly (5) being characterized in that it com¬prises a body (50) to which a sealing element (51) is associated, which is compressible when the chamber (4) is pressed against the engine housing (2). 11. An assembly according to claim 10, characterized in that the body (50) is substantially cylindrical in shape, and the sealing element (51) is substantially in the form of a resilient ring. 12. An assembly according to claim 11, characterized in that it seals the first through bore (2') of the engine housing (2) and the second through bore (4') of the chamber (4) for positioning the shaft driving means when the latter is associated to the housing (2). 13. An assembly according to claim 12, characterized in that the body (50) is made from 1010 steel. 14. An assembly according to claim 13, characterized in that the body (50) is associable to the chamber (4) by screwing.

Documents:

94-CHE-2005 AMENDED PAGES OF SPECIFICATION 15-04-2013.pdf

94-CHE-2005 AMENDED CLAIMS 15-04-2013.pdf

94-CHE-2005 CORRESPONDENCE OTHERS 09-11-2012.pdf

94-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 12-10-2012.pdf

94-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 15-04-2013.pdf

94-CHE-2005 FORM-1 15-04-2013.pdf

94-CHE-2005 FORM-3 15-04-2013.pdf

94-CHE-2005 OTHER PATENT DOCUMENT 15-04-2013.pdf

94-CHE-2005 POWER OF ATTORNEY 15-04-2013.pdf

94-CHE-2005 ABSTRACT.pdf

94-CHE-2005 CLAIMS.pdf

94-CHE-2005 CORRESPONDENCE OTHERS.pdf

94-CHE-2005 DESCRIPTION (COMPLETE).pdf

94-CHE-2005 DRAWINGS.pdf

94-CHE-2005 FORM 1.pdf

94-CHE-2005 FORM 18.pdf

94-CHE-2005 FORM 3.pdf

94-CHE-2005 FORM 5.pdf