Lubrication Apparatus in Internal Combustion Engine

1. Field of the Invention

This invention relates to a lubrication apparatus in an internal combustion engine chiefly used for a vehicle.

2. Description of the Prior Art

Prior art lubrication systems are used in which an oil pan is detachably provided on the lower surface of a crank chamber of an internal combustion engine in order to close the crank chamber. An oil pump having an oil intake opening and an oil filter which is in communication with the oil pump through a communication passage are provided in the crank chamber, and the communication passage has a relief valve arranged to be opened by an oil pressure above a predetermined value. Normally, in this type of apparatus, the relief valve is fixed to the pump or the crank chamber by being fastened thereto by means of a screw or the like, and accordingly, this arrangement results in difficulty in attaching and detaching of the relief valve and requires much trouble and nuisance.

It is an object of the present invention to provide a lubrication apparatus in which a relief valve in the oil passage between the oil pump and oil filter, is supported by the oil pan without the need for a screw, thereby facilitating the insertion and removal of the valve and making the mounting more stable.

The present invention is directed to a lubrication apparatus for an internal combustion engine having a crank chamber with an oil pan detachably mounted on the lower surface of the crank chamber. An oil pump and an oil filter are coupled together by an oil passage in the crank chamber. A relief valve is provided in the oil passage, the relief valve being opened by an oil pressure above a predetermined value. The oil passage includes an opening directed towards the oil pan and the oil pan includes a rib formed on the upper surface thereof, wherein the relief valve is inserted in the opening and is supported therein by the rib.

FIG. 1 is a side view, partly omitted, of the preferred embodiment of the present invention.

FIG. 2 is an enlarged partial sectional side view thereof.

Referring to the drawings, an internal combustion engine 1 has a crank chamber 2. An oil pan 3 is detachably mounted on the lower surface of the crank chamber 2 by being fastened thereto by means of a screw 4 or the like. An oil pump 6 having an oil intake opening 5, and an oil filter 8 communicates with the oil pump 6 through a communication passage 7 located in the crank chamber 2. The communication passage 7 is provided with a relief valve 9 which is opened by an oil pressure above a predetermined value.

According to this invention, the communication passage 7 has an opening 10 therein which is directed towards the oil pan 3 and the relief valve 9 is inserted in the opening 10 and is supported from behind by the oil pan 3.

In the above embodiment, the oil pan 3 has a rib 11 on its upper surface which supports the valve 9, and in this case, the rib 11 is made so that its thickness is comparatively small. The relief valve 9 comprises a surrounding tubular casing 9a and a valve body 9b slidably mounted therein. A chamber 9c defined in the valve body 9b communicates with the exterior through an opening 9d made in the lower surface thereof, and in this case, the rib 11 has a thickness smaller than the opening 9d.

A plurality of screws 4 are disposed at spaced intervals on the peripheral portion of the oil pan 3, and each screw 4 lies on an axial line which is in parallel with the axial line of the tubular opening 10.

A tube which forms the communication passage 7 and an oil filter screen 5a which covers an open end portion of the intake opening 5 are also supported from below by the oil pan 3. In particular, the tube 7 is supported from below by a rib 12 formed on the upper surface of the oil pan 3, and the screen 5a is supported from below by a rib 13 formed on the upper surface of the oil pan 3.

The pump 6 is driven by an output shaft 14 of the engine 1 through a chain 15 or the like, and the oil filter 8 is in communication on its outlet side with an oil supply passage 16.

Referring to the drawings, numeral 17 denotes a tubular guide member surrounding the tubular casing 9a of the relief valve 9, and the same serves to form therein an oil guide passage 17a extending downwards.

Thus, according to this invention, the relief valve is inserted in the opening in the communication passage and is supported from below by the oil pan, so that attaching and detaching of the valve is simpler and easier than in a conventional apparatus in which the valve is fastened by means of a screw. Furthermore, the attached condition thereof becomes more stable.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, to be embraced therein.