Marine propulsion – Screw propeller – With vibration dampening
Reexamination Certificate
1999-07-14
2001-02-13
Morano, S. Joseph (Department: 3617)
Marine propulsion
Screw propeller
With vibration dampening
C440S012610
Reexamination Certificate
active
06186844
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an outboard motor particularly provided with a balancer device having an improved arrangement.
An outboard motor is generally equipped with an engine or engine unit which is driven through an operation of a piston-cylinder assembly and generates a primary vibration caused by reciprocal motion of a piston. In order to eliminate such vibration, an outboard motor is provided with a balancer or balancer device.
The balancer is generally composed of a balancer weight which is mounted to a balancer shaft arranged in parallel to a crank shaft disposed inside the engine and which has a weight corresponding to the total weight of the piston, a connection rod and so on. The balancer shaft is driven in association with the driving motion of the crank shaft thereby to remove the primary vibration at the time of the engine operation.
However, in a general structure of the engine of an outboard motor, the balancer shaft is arranged substantially perpendicularly as well as the crank shaft, which causes problems of sealing and/or lubricating an upper bearing portion of the balancer shaft.
In a prior art, although the sealing and lubrication of the bearing portion of the crank shaft have been sufficiently considered, those of the balancer shaft have not been sufficiently considered.
SUMMARY OF THE INVENTION
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide an outboard motor provided with an improved arrangement of the balancer device for achieving the sealing and lubricating an upper bearing portion of a balancer shaft with a simple structure.
This and other objects can be achieved according to the present invention by providing, in one aspect, an outboard motor of a structure in which a balancer shaft is arranged in a crank chamber of an engine unit substantially in parallel to a crank shaft disposed therein so as to perpendicularly extend in an operative state of an outboard motor and end portions of the balancer shaft are supported by bearing means,
wherein end portions of the crank shaft and the balancer shaft are covered and sealed by a seal member straddling over both the end portions thereof.
In this aspect, the seal member has a back surface having a portion directly above the end portion of the balancer shaft at which an oil reservoir is formed and another oil reservoir is formed to a portion surrounding the crank shaft, the one and another oil reservoirs being communicated with each other by means of communication passage formed to the back surface of the seal member thereby to guide a lubrication oil introduced to the crank shaft to the bearing means supporting the balancer shaft.
In a more detailed aspect, there is provided an outboard comprising:
an engine holder;
an engine unit disposed above the engine holder so as to be held by the engine holder in a usable state of an outboard motor, said engine unit including a cylinder head, a cylinder block and a crank case having a crank chamber in which a crank shaft extends perpendicularly;
a balancer device disposed in association with the crank shaft so as to remove vibration generated at a time of engine operation, said balancer means including a balancer shaft disposed in the crank chamber substantially parallel to the crank shaft, said balancer shaft being supported by means of bearing and operatively rotated in association with rotation of the crank shaft; and
a seal member mounted to the crank chamber straddling over end portions of the crank shaft and the balancer shaft so as to seal both the end portions.
In this aspect, the seal member is an oil seal housing having a flat plate member straddling over end portions of the crank shaft and the balancer shaft so as to seal both the end portions of the crank shaft and the balancer shaft.
The outboard motor further includes a lubrication structure including a first reservoir formed to the flat plate member at a portion directly above the end portion of the balancer shaft, a second oil reservoir formed to a portion surrounding the crank shaft, and a communication passage, for communicating the first and second oil reservoirs with each other, formed to a back surface of the plate member thereby to guide a lubrication oil introduced to the crank shaft to the bearing means supporting the balancer shaft. The communication passage is formed as a groove.
According to the structure of the preferred embodiment of the present invention described above, the upper portions of the crank shaft and the balancer shaft disposed inside the crank chamber formed by mating the cylinder block and the crank case are sealed by the oil seal member having the flat plate member covering both the upper ends of the crank shaft and the balancer shaft, so that the bearing portions of both the shafts can be sealed with a few members through easy assembling process, resulting in a cost reducing.
Furthermore, the communication passage groove is formed so as to establish the communication between both the oil reservoirs formed to the portion directly above the balancer shaft and the surrounding of the crank shaft, respectively, so that the lubrication oil guided to the crank shaft is guided to the ball bearings supporting the balancer shaft. According to such structure, it is not necessary to locate any private oil lubrication passage for the bearings supporting the balancer shaft, thus being convenient and economical in manufacturing cost.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.
REFERENCES:
patent: 4846124 (1989-07-01), Suzuki et al.
patent: 5309877 (1994-05-01), Shigedomi et al.
patent: 5401199 (1995-03-01), Shibata
patent: 5461940 (1995-10-01), Morita
patent: 5537968 (1996-07-01), Takahashi
Saiga Jiro
Yonezawa Atsushi
Morano S. Joseph
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Suzuki Kabushiki Kaisha
Vasudeva Ajay
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