Internal-combustion engines – Lubricators – Crankcase – pressure control
Reexamination Certificate
1999-08-31
2001-01-23
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Lubricators
Crankcase, pressure control
Reexamination Certificate
active
06176214
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lubricating structure for an internal combustion engine and, more particularly, to an improvement of lubricating ability on an inner face of a cylinder liner.
2. Description of the Related Art
Generally, lubricating oil in the internal combustion engine is sucked up from an oil pan through the intermediary of a strainer by an oil pump. Thereafter, the pressure of lubricating oil is controlled by a pressure governor and subsequently, the oil is fed to a main gallery. Formed to branch off from the main gallery are respective oil holes (or lubricant passages) through which the lubricating oil is supplied to respective lubricating sections, for example, a moving valve system, the crankshaft and so on.
Hereat, the lubricating oil for each lubricating section of the crankshaft is firstly fed from the main gallery to a main journal and sequentially fed to a pin journal through an oil hole (passage) penetrating both crankshaft and crank pin and finally reaching the crank pin. Thereafter, the lubricating oil is drained into an oil pan through a clearance between the main journal and the crankshaft and another clearance between the pin journal and the crank pin. While, the lubricating oil brought to each pin journal passes through a splash oil hole having one end opening at the inner face of a circular hole for bearing the crank pin of the pin journal and the other end opening at a base of a connecting-rod as a lubricant injection nozzle. Next, on completion of the piston lubrication, the lubricating oil is returned to the oil pan.
Here, regarding the formation of both splash oil hole of the connecting-rod and oil hole penetrating the crankshaft for the pin journal, there is a known lubricating structure where the arrangement of both holes are established such that, when the position of the former oil hole coincides with the position of the latter hole, then the lubricating oil ejected from the splash oil hole is supplied against the inner face of the cylinder liner (see Japanese Unexamined Patent Publication No. 9-280027).
However, since the above-mentioned earlier art has been provided on only consideration to coincide the position of the splash oil hole with the position of the oil hole of the pin journal when the splash oil hole faces to the inner face of the cylinder liner, there is not defined a positional relationship between the oil hole in the main journal communicating with the main gallery and the oil hole formed in the crankshaft. That is, even when the position of the splash oil hole agrees with the position of the oil hole of the pin journal, the position of the oil hole on the main journal's side does not coincide with that of the oil hole formed in the crankshaft.
Therefore, the lubricating oil, which has been supplied from the oil hole of the main journal at the positional incidence between the splash oil hole and the oil hole of the pin journal, is introduced into the oil hole of the crankshaft through a groove section between the crankshaft and the main journal.
In such a lubricating route, due to a great reduction in lubricant pressure at the groove section between the crankshaft and the main journal, it is not possible to ensure a sufficient amount of lubricant ejected from the splash oil hole via the oil hole of the crankshaft and the sequential oil hole of the crank pin. Especially, since the lubrication on the inner face of the cylinder liner is insufficient at the vehicle's cold starting, the earlier art lubricating structure cannot perform sufficient effect to reduce the piston slap.
SUMMARY OF THE INVENTION
Under such a circumstance, it is an object of the present invention to improve the structure's lubricating ability on the inner face of the cylinder liner in order to reduce the piston slap, together with the oil hole arrangement where the lubricant route from the main gallery up to the splash oil hole via the main journal, the crankshaft and the crank pin is constructed just like a single oil passage.
According to the invention, the above-mentioned object is accomplished by a lubricating structure for an internal combustion engine, comprising:
a first oil hole formed in a main journal to communicate with a main gallery provided in a cylinder block;
a crankshaft having a second oil hole formed so as to communicate with the first oil hole of the main journal;
at least one crank pin formed on the crankshaft to rotate about a center of the crankshaft, the crank pin having a third oil hole formed for communication with the second oil hole of the crank shaft;
a connecting-rod rotatably fitted on the crank pin and also provided, at a base part thereof, with a splash oil hole which is constructed so as to communicate with the third oil hole of the crank pin and which has an end opening at an inner face of a circular inner face of a bore for bearing the crank pin and the other end opening at the base part of the connecting-rod as an ejecting port for lubricating oil;
wherein the first, second and third oil holes and the splash oil hole are constructed so that, when the position of the splash oil hole coincides with the position of the third oil hole, the position of the first oil hole coincides the position of the second oil hole while the splash oil hole directs itself toward an inner peripheral face of a cylinder liner.
Providing that, in view of the axial direction of the crankshaft,
&agr; represents an angle in a rotating direction of the crankshaft, the angle being made by both of an extension line on the side of the crank pin of a line linking a center of the crankshaft with a center of the crank pin and a line linking the center of the crank pin with an opening of the third oil hole opening at the outer face of the crank pin;
&bgr; represents an angle between a center line of the connecting-rod and a line linking the center of the crank pin with the opening of the splash oil hole on the side of the inner face of the pin journal, in the opposite direction of the rotating direction of the crankshaft;
&ggr; represents an angle between the line linking the center of the crankshaft with the center of the crank pin center and a line linking the center of the crankshaft with an opening of the second oil hole opening at the outer face of the crankshaft, in the rotating direction of the crankshaft;
r represents a distance between the center of the crankshaft and the center of the crank pin;
l represents a distance between respective rotating centers on both sides of the connecting-rod; and
&tgr; represents an angle between a cylinder bore's center line passing through a center of the main journal and a line linking the center of the crankshaft with the opening of the first oil hole at the inner face of the main journal, in the rotating direction of the crankshaft, it is preferable that respective positions of the first, second and third oil holes and the splash oil hole are determined so as to meet a relationship of:
γ
=
τ
-
tan
-
1
{
-
sin
(
α
+
β
)
(
r
/
l
)
+
cos
(
α
+
β
)
}
The above and other features and advantages of this invention will become apparent, and the invention itself will best be understood, from a study of the following description and appended claims, with reference to the attached drawings showing one preferred embodiment of the invention.
REFERENCES:
patent: 3785459 (1974-01-01), Patchen
patent: 3842938 (1974-10-01), Barnes-Moss
patent: 5039285 (1991-08-01), Lindstrom
patent: 5174249 (1992-12-01), Katou
patent: 5533472 (1996-07-01), Sands et al.
patent: 26 47 441 (1976-10-01), None
patent: 116092 (1942-10-01), None
Ali Hyder
Foley & Lardner
Nissan Motor Co,. Ltd.
Wolfe Willis R.
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