Internal combustion engine for motor vehicles

Abstract: An internal combustion engine for motor vehicles in which a gasket (15) with arcuate portions complementary to those of the end caps is interposed between the retaining caps (4) for the ends of the or each camshaft (10) and the cover (8) of the head (1). Each of the caps has an outer surface formed with a plurality of alternating, parallel grooves and projections (7, 6) engaged with complementary projections and grooves (10, 19) of the corresponding arcuate portion of the gasket.

Description: The present invention relates to an internal combustion engine for motor vehicles,having a head, at least one camshaft supported for rotation by bearings formed in the head, respective arcuate retaining caps fixed to. the bearings, in which the bearing and the respective cap for at least one end of the shaft are adjacent the peripheral edge of the head, a cover for the head having a peripheral edge which is fixed to that of the head and, in correspondence with the end cap, has a portion of complementary arcuate profile, and a gasket which is interposed between the fixing edges of the head and the cover and has an arcuate portion interposed between the end cap and the said portion of the fixing edge of the cover of complementary arcuate profile. In an engine of this type, which is known from FR-A-2 526 864, the regions of the head most prone to leakage of the lubricating oil in operation are precisely those corresponding to the ends of the or each camshaft, particularly in correspondence with the arcuate sealing surfaces between the end retaining caps and the gasket of the cover. The ends of the caps closest to the peripheral edge, according to said FR-document, are construted with a groove. The gasket has corresponding ridges. Solutions proposed up to now in an attempt to solve this problem consist of the use of additional fixing screws between the cover and the head adjacent the critical regions, the tightening of the screws being intended to compress the gasket as uniformly as possible. This solution is inadequate, however, since it does not completely eliminate the risk of oil leakage. The object of the present invention is to solve this problem and to provide an internal combustion engine for motor vehicles of the type defined above, in which there is effectively no risk of leakage of the lubricating oil in correspondence with the projecting ends of the camshaft or camshafts. According to the invention, this object is achieved by virtue of the fact that the or each end cap has an outer surface formed with a plurality of alternating, parallel grooves and projections extending from one end of the arc of the arcuate profile of the cap to the other end and the corresponding arcuate portion of the gasket has an inner surface formed with a plurality of alternating, parallel projections and grooves engaged respectively with the grooves and projections of the outer surface of the end cap. According to a preferred embodiment of the invention, the grooves and projections have V-shaped cross-sections with corresponding dimensions. According to a variant, the projections have V-shaped cross-sections and the grooves are wider than the projections. Both embodiments provide a sealing surface constituted by a row of successive barriers formed by the resilient compression of the gasket as a result of its being clamped between the head and the cover. The invention will now be described in detail with reference to the appended drawings, provided purely by way of non-limiting example, in which: Figure 1 is a schematic vertical section of part of an internal combustion engine for motor vehicles according to the invention, Figure 2 is an exploded perspective view of part of Figure 1, Figure 3 shows a detail of Figure 1 on an enlarged scale, and Figure 4 shows a variant of Figure 3. With reference first to Figures 1 and 2, a part of the head of an internal combustion engine for motor vehicles, schematically indicated 1, has a peripheral connecting flange 2 at its top and, adjacent thereto, a bearing 3 for an end of a camshaft 10 which projects from one end of the head 1 for the mounting of a drive pulley 11. In conventional manner, an end cap 4 is fixed to the bearing 3 to retain the end of the camshaft rotatably. The cap 4 has a portion 5 of semicircular profile in which a shaft sealing ring 16 for the end of the camshaft 10 is arranged with its lower portion bearing against a semicircular recess 12 in the peripheral flange 2 of the head 1. The outer surface of the arcuate part 5 of the cap 4 is formed with a series of alternating, adjacent projections 6 and grooves 7 which, as can be seen better in Figure 3, have identical V-shaped cross-sections. A cover, indicated 8, has a peripheral connecting flange 9 at its bottom complementary to the flange 2 of the head 1. In correspondence with the recess 12 in the latter, the connecting flange 9 in turn has a corresponding semicircular recess 13 in the central region of which is formed a channel 14 which extends around the entire flange 9. A gasket 15 of resiliently compressible material is interposed between the connecting flanges 2 and 9 of the head 1 and the cover 8 respectively. The gasket 15 has a semicircular portion 17 arranged between the semicircular recess 13 of the cover 8 and the semicircular part 5 of the cap 4 and an upper rib 18 inserted in the channel 14 in the cover 8. The inner surface of the semicircular portion 17 of the gasket 15 is formed with a plurality of grooves 19 and projections 20 complementary to the projections 6 and grooves 7 of the cap 4 and engaged therewith. When the cover 8 is mounted on the head 1, the gasket 15 is clamped between the connecting flanges 9 and 2 so that its semicircular portion 17 is compressed between the semicircular portion 13 of the cover 8 and the semicircular portion 5 of the cap 4. As a result of this compression, a plurality of adjacent sealing barriers are formed between the projections 20 and the grooves 7 on the one hand and between the projections 6 and the grooves 19 on the other hand and, in use, these prevent any leakage of lubricating oil in the region where the end of the camshaft 10 projects from the head 1. According to the variant of Figure 4, in which parts identical or similar to those described above are indicated by the same reference numerals, the shapes of the grooves 7 in the semicircular part 5 of the cap 4 and of the grooves 19 in the semicircular part 17 of the gasket 15 differ from those of the respective projections 6 and 20, unlike the embodiment described above. In fact, the grooves 7, 19 are wider than the projections 6, 20 so that they define intermediate sealing chambers 21 therewith.

Claims: An internal combustion engine for motor vehicles, having a head (1), at least one camshaft (10) supported for rotation by bearings (3) formed in the head, respective arcuate retaining caps (4) fixed to the bearings, in which the bearing (3) and the respective cap (4, 5) for at least one end of the shaft are adjacent the peripheral edge (2) of the head, a cover (8) for the head having a peripheral edge (9) which is fixed to that of the head and, in correspondence with the end cap (4, 5), has a portion (13) of complementary arcuate profile, and a gasket (15) which is interposed between the fixing edges (2, 9) of the head and the cover and has an arcuate portion (17) interposed between the end cap (4, 5) and the said portion (13) of the cover of complementary arcuate profile, characterised in that the end cap (4) has an outer surface (5) formed with a plurality of alternating, parallel grooves (7) and projections (6) extending from one end of the arc of the arcuate profile of the cap (4,5) to the other end and the corresponding arcuate portion (17) of the gasket (15) has an inner surface formed with a plurality of alternating, parallel projections (20) and grooves (19) engaged respectively with the grooves (7) and projections (6) of the outer surface (5) of the end cap (4). An engine according to Claim 1, characterised in that the grooves (7, 19) and projections (6, 20) have V-shaped cross-sections with corresponding dimensions. An engine according to Claim 1, characterised in that the projections (6, 20) have V-shaped cross-sections and the grooves (7, 19) are wider than the projections.

Inventors: FERRAZZI FRANCESCO, FERRAZZI, FRANCESCO
Applicants: FIAT AUTO SPA, FIAT AUTO S.P.A.
Application year: 1991
Main classification: F02F7
IPC codes: F16J15, F02F7, F02F11