Internal-combustion engines – Cooling – Internal cooling of moving parts; e.g. – hollow valves,...
Reexamination Certificate
2001-01-09
2002-11-19
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Cooling
Internal cooling of moving parts; e.g., hollow valves,...
C123S1960CP
Reexamination Certificate
active
06481389
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a piston oil-cooling device in an engine in which a crankcase that supports journals of a crankshaft is provided with lubricating oil passages to supply oil to outer peripheral surfaces of the journals. The crankshaft is provided with lubricating oil bores to supply the oil from the journals to an outer peripheral surface of a crank pin and a piston is cooled from its backside by using the oil to lubricate portions around the crank pin.
2. Description of the Related Art
Conventional piston oil-cooling devices in engines typically include a piston oil-cooling device in a horizontal engine with a crankshaft disposed horizontally. An oil dipper is formed at a larger end of a connecting rod so that oil in an oil pan at a bottom of a crankcase is scattered by the oil dipper due to the rotation of the crankshaft. The scattered oil is permitted to reach a backside of a piston to cool the piston. The conventional piston oil-cooling devices also typically include another piston oil-cooling device having an oil injection bore provided in the larger end of the connecting rod to communicate with a lubricating oil bore in the crankshaft so that a piston is cooled from its backside by the oil injected from the oil injection bore. See Japanese Utility Model Publication No.4-37211.
Unfortunately, the first-mentioned conventional device is not applicable to a vertical engine with a crankshaft that is disposed vertically. Also, the second-mentioned conventional device is applicable to either horizontal and vertical engines, but suffers from a drawback in that much labor is needed to make the oil injection bore in the larger end of the connecting rod by drilling, which results in an increase in cost, as well as manufacturing time and effort.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a piston oil-cooling device applicable to either horizontal and vertical engines, wherein a piston can be reliably cooled from its backside by using an oil to lubricate portions of a crank pin of a crankshaft, wherein the oil injection bore can easily be made, which reduces manufacturing time and effort, thereby reducing cost.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a piston oil-cooling device in an engine in which a crankcase that supports journals of a crankshaft is provided with lubricating oil passages to supply oil from an oil pump to outer peripheral surfaces of the journals. The crankshaft is provided with lubricating oil bores to supply the oil from the journals to an outer peripheral surface of a crank pin. A larger end of a connecting rod connected to the crank pin is provided in an inner peripheral surface with a pair of opposed axial oil grooves. The larger end is also provided in a side thrust face with an annular oil passage connected to the axial groove and a cooling oil injection groove. The cooling oil injection groove is connected at one end thereof to the annular oil passage while the other end is directed to a backside of a piston which is connected to a smaller end of the connecting rod.
With the first feature, when the lubricating oil bores in the crankshaft are aligned with the axial oil grooves in the larger end of the connecting rod, the oil in the lubricating oil bores is injected from the cooling oil injection groove via the axial oil grooves and the annular oil passage in the larger end toward the backside of the piston to effectively cool the piston. Therefore, the force of the injected oil is always strong and reaches the piston properly, thereby effectively cooling the piston. Thus, the piston oil-cooling device is applicable to either vertical and horizontal engines. Moreover, the cooling oil injection groove, the annular oil passage, and the axial oil grooves can be manufactured simultaneously with the formation of the connecting rod, thereby reducing manufacturing time and effort, as well as cost.
According to a second aspect and feature of the present invention, in addition to the first feature, a pair of the cooling oil injection grooves are disposed in proximity to the pair of axial oil grooves on the same side thrust face, respectively.
With the second feature, the pair of cooling oil injection grooves are in proximity to the pair of axial oil grooves, respectively. Therefore, when the lubricating oil bores in the crankshaft are aligned with each of the axial oil grooves, the oil is injected, having a particularly strong force, from the cooling injection groove closer to the axial groove. Such a situation occurs once per rotation of the crankshaft and hence, the oil cooling of the piston can be carried out more effectively.
According to a third aspect and feature of the present invention, in addition to the first or second feature, when the engine is of a vertical type with a crankshaft disposed vertically, the cooling oil injection groove is provided in a lower side thrust face of the larger end.
With the third feature, the opposed side thrust faces of the larger end and the crankshaft are brought into close contact by the weight of the connecting rod. Therefore, leakage of the cooling oil from the cooling oil injection groove in the larger end of the connecting rod between both of the side thrust faces is eliminated to maintain the injection force of the oil from the cooling oil injection groove. Also, oil injected from the cooling oil injection groove is permitted to easily reach the piston without being obstructed by the connecting rod, thereby further effectively achieving the oil cooling of the piston.
According to a fourth aspect and feature of the present invention, in addition to the first or second feature, a side thrust face of the crankshaft opposed to the side thrust face of the larger end is formed to cover the entire open surface of the cooling oil injection groove.
With the fourth feature, the open surface of the cooling oil injection groove in the larger end of the connecting rod is closed by the side thrust face of the crankshaft. Therefore, it is possible to prevent a wasteful flowing-out of the cooling oil from the open surface of the cooling oil injection groove and to maintain the injection force of the oil from the cooling oil injection groove, thereby more effectively achieving the oil cooling of the piston.
According to a fifth aspect and feature of the present invention, in addition to the first or second feature, the larger end is comprised of a semi-cylindrical larger end body integrally formed at a rod portion, and a semi-cylindrical cap coupled to the larger end body, and the pair of axial oil grooves are provided at a boundary between the larger end body and the cap.
With the fifth feature, it is possible to avoid the damage to the outer peripheral surface of the crank pin by the boundary between the larger end body and the cap by using the axial oil grooves.
The above and other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3739657 (1973-06-01), Patchen et al.
patent: 3785459 (1974-01-01), Patchen
patent: 5482380 (1996-01-01), Corrati et al.
patent: 6032635 (2000-03-01), Moorman et al.
patent: 437211 (2002-02-01), None
Suzuki Nobuo
Tanaka Mitsuharu
Yoshida Hiroyuki
Arent Fox Kintner & Plotkin & Kahn, PLLC
Honda Giken Kogyo Kabushiki Kaisha
Smith Rebecca A
Wolfe Willis R.
LandOfFree
Piston oil-cooling device in an engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Piston oil-cooling device in an engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Piston oil-cooling device in an engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2991562