Internal-combustion engines – Cooling – With liquid coolant circulating means
Reexamination Certificate
1999-09-14
2001-04-10
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Cooling
With liquid coolant circulating means
Reexamination Certificate
active
06213063
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a water pump for a water-cooled engine.
2. Description of Related Art
Japanese Utility Model Publication No. Hei 6-31197 discloses a structure of a water pump for a water-cooled engine of a motorcycle. In the water pump, an impeller is attached to one end of a hollow pump shaft, and a pump gear is attached to the other end of the pump shaft. The pump gear rotates in response to rotation of a crankshaft. The pump shaft is supported by a crankcase of the crankshaft.
The pump gear receives a thrust load from a pin. The pin has its opposite ends supported in the crankcase via the pump gear and is orthogonal to the crankcase. The pump gear is surface-supported by the crankcase.
In order to receive the thrust load by the pin, as described above, a drilling process and a force-fitting process are required in order to install the pin. Therefore, the number of components, including the pin itself, is increased. Further, the manufacturing and repair process is difficult. In order to support the pump shaft at the opposite ends thereof, the pump shaft should be centered very precisely. Therefore, the pump shaft is preferably supported at one end thereof
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome one or more of the drawbacks associated with the background art.
It is a further object of the present invention to provide a water pump including a water pump shaft for rotatably supporting a water pump impeller, wherein the water pump shaft is directly and rotatably attached to a water pump body via a shaft support section.
It is a further object of the present invention to provide a water pump including a water pump shaft having an engaging portion formed at one end, opposite to an end where the impeller is supported.
It is a further object of the present invention to provide a method of forming a water pump shaft including a flange.
These and other objects are accomplished by providing a water pump for an engine comprising: a water pump body having an approximately cylindrical support section of a first diameter and a first length, wherein said first length is longer than said first diameter; a water pump shaft having a first end, a second end, and a second diameter, said second diameter being approximately equal to said first diameter, said water pump shaft lying within said cylindrical support section to be directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; and an engaging portion included proximate said second end for causing said water pump shaft and said water pump impeller to rotate relative to said water pump body.
Further, these and other objects are accomplished by providing an engine comprising: a crank case; a crank shaft rotatably mounted in said crank case; a driven member interacting with said crank shaft to rotate in response to rotation of said crankshaft; a first engaging member connected to said driven member to rotate therewith; a water pump body attached to said engine; a water pump shaft having a first end and a second end, said water pump shaft being directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; and a second engaging member included proximate said second end, said second engaging member being engaged by said first engaging member to cause said water pump shaft and said water pump impeller to rotate in response to rotation of said first engaging member.
Moreover, these and other objects are accomplished by providing a method of forming a water pump shaft of a water pump comprising the steps of: providing a die with a cylindrical opening of a first diameter formed therein; a punch having a circular groove formed in an end thereof with a protruding cylindrical portion inside the circular groove, the cylindrical protruding portion having a second diameter; and a hollow shaft with a third outer diameter approximately equal to the first diameter and a fourth inner diameter approximately equal to the second diameter; inserting one end of the hollow shaft into the circular opening of the die; inserting the cylindrical protruding portion into the hollow shaft until the hollow shaft seats into the circular groove; moving the punch toward the die; inserting the cylindrical protruding portion into the circular opening; and bending the hollow shaft in a radial direction at a point where the hollow shaft enters the die.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 869887 (1907-11-01), Duryea
Kobayashi Chutaro
Nakano Shin'ichi
Oka Tomoo
Suzuki Yoshiki
Takahashi Katsunori
Birch & Stewart Kolasch & Birch, LLP
Harris Katrina B.
Honda Giken Kogyo Kabushiki Kaisha
Wolfe Willis R.
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