Shield structure for internal combustion engine

Abstract

The present invention provides a shield structure for an internal combustion engine. The shield structure of the internal combustion engine can be reduced in weight and can ensure sufficient sealing performance of the oil seal and the gasket.The shield structure of the internal combustion engine includes a shield member (11) which is made of resin and which can be attached to the main body (2) of the internal combustion engine in such a manner as to cover the power transmission portion (5); and a holding member (13) which is made of metal, and the holding member holds the oil seal (12) pressed against the outer peripheral surface of the crankshaft.Further, the holding member is engaged with the main body of the internal combustion engine so as to be able to be positioned in the axial direction of the crankshaft and in the plane direction orthogonal to the axial direction.Further, a gasket (45) sandwiched between the shroud member and the holding member so as to surround the crankshaft is fastened by the fastening bolt (37).

Description

technical field [0001] The present invention relates to a shroud structure of an internal combustion engine, and more specifically, to a shroud structure of an internal combustion engine for covering a power transmission portion that transmits power from a crankshaft to a camshaft of the internal combustion engine. Background technique [0002] As a conventional shroud structure of an internal combustion engine, a shroud structure that covers a power transmission portion (such as a timing chain, etc.) that transmits power from a crankshaft to a camshaft of the internal combustion engine is generally known. For example, if Figure 19 As shown, this shroud structure 110 includes a metal shroud member 111 that can be attached to the main body 102 of the internal combustion engine (for example, a cylinder block, etc.) so as to cover the power transmission unit 105 . Further, a through hole 118 for the crankshaft 103 is formed in the guard member 111 , and an oil seal 112 press-c...

AI Technical Summary

Problems solved by technology

[0005] However, in the technology disclosed in the aforementioned Japanese Patent Laid-Open No. 2015-102018, the oil seal 212 is held on the inner peripheral side of the through-hole 218 of the resin cover member 211, so it is difficult to satisfy the required size of the oil seal 212.

That is, the size of the resin cover member 211 tends to change in the radial direction of the crankshaft 203 due to the pressing force, heat, pressure, and creep of the oil seal 212, so that sufficient sealing performance of the oil seal 212 cannot be ensured.

Moreover, it is difficult to arrange the fastening bolts 214 around the crankshaft where parts such as sprockets and pulleys are concentrated.

In addition, another seal member 209 needs to be arranged between the fastening bolt 214 and the cover member 211, and therefore, there are restrictions on mounting.

[0006] Furthermore, in the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2015-071996, it is a structure in which the outer periphery of the gasket 345 is compressed by bringing the metal holding member 313 into contact with the resin cover member 311 . Therefore, the dimensional tolerance increases and the difference in the compressibility of the gasket 345 becomes larger

Furthermore, although the washer 345 is arranged around the oil seal 312, the washer 345 is compressed by the fastening force of the fastening bolt 314 on the outer peripheral side, so the washer 345 cannot be compressed sufficiently, and the sealing performance of the washer 345 cannot be ensured. adequate sealing performance

Furthermore, when the resin shield member 311 is deformed by heat or pressure, the compressibility of the gasket 345 decreases, and there is a possibility of oil leakage.

Moreover, after the peripheral side of the resin shroud member 311 is fastened to the main body 302 of the internal combustion engine, the peripheral side of the metal holding member 313 is fastened to the main body 302 of the internal combustion engine. Therefore, the metal holding member 313 increase in size and weight

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